Philosophy of Memory

On the one hand, "...olfaction is our slow sense, for it depends on messages carried not at the speed of light or of sound, but at the far statelier pace of a bypassing breeze, a pocket of air enriched with the sort of small, volatile molecules that our nasal-based odor receptors can read.

Yet, on the other hand, olfaction is our quickest sense. Whereas new signals detected from the visual system, auditory system, proprioception (body position), nociception (pain) and gustation (taste) "must first be assimilated by a structural way station called the thalamus before reaching the brain’s interpretive regions, odiferous messages barrel along dedicated pathways straight from the nose and right into the brain’s olfactory cortex, for instant processing. Importantly, the olfactory cortex is embedded within the brain’s limbic system and amygdala, where emotions are born and emotional memories stored. That’s why smells, feelings and memories become so easily and intimately entangled...

...numerous studies have shown that smell memory is long and resilient, and that the earliest odor associations we make often stick...

...while the word and visual cues elicited associations largely from subjects’ adolescence and young adulthood, the smell cues evoked thoughts of early childhood, under the age of 10. And despite the comparative antiquity of such memories, Dr. Larsson said, people described them in exceptionally rich and emotional terms, and they were much likelier to report the sudden sensation of being brought back in time...

...Dr. Larsson attributes the youthfulness of smell memories to the fact that our olfaction is the first of our senses to mature and only later cedes cognitive primacy to vision and words, while the cortical link between olfaction and emotion ensures that those early sensations keep their bloom all life long."

Link

Perception is one of the most basic epistemic sources we have. Yet, most epistemologists spend their entire philosophical lives using examples from vision(e.g. apprehending objects) or audition (e.g. understanding assertions). Perhaps olfaction is the most basic of all the senses, in the sense that the signal from external stimuli is least compromised by interpretation during its path to consciousness? All other sensory inputs must survive selective processing by the thalamus and an unpredictable journey to various parts of the cerebral cortex.

Even though most people struggle to identify smells conceptually, they can recognise smells with great reliability and also trigger memories more powerfully than almost any other stimulus: internal or external. In fact, when considering how we bootstrap ourselves into the world; how we align our experience of the world with what exists; perhaps olfaction is the biggest piece of leather?

The brain does not simply gather and stockpile information as a computer's hard drive does. Facts are stored first in the hippocampus, a structure deep in the brain about the size and shape of a fat man's curled pinkie finger. But the information does not rest there. Every time we recall it, our brain writes it down again, and during this re-storage, it is also reprocessed. In time, the fact is gradually transferred to the cerebral cortex and is separated from the context in which it was originally learned. For example, you know that the capital of California is Sacramento, but you probably don't remember how you learned it.

This phenomenon, known as source amnesia, can also lead people to forget whether a statement is true. Even when a lie is presented with a disclaimer, people often later remember it as true.

With time, this misremembering gets worse. A false statement from a noncredible source that is at first not believed can gain credibility during the months it takes to reprocess memories from short-term hippocampal storage to longer-term cortical storage. As the source is forgotten, the message and its implications gain strength...

...Psychologists have suggested that legends propagate by striking an emotional chord. In the same way, ideas can spread by emotional selection, rather than by their factual merits, encouraging the persistence of falsehoods...

...Journalists and campaign workers may think they are acting to counter misinformation by pointing out that it is not true. But by repeating a false rumor, they may inadvertently make it stronger. In its concerted effort to "stop the smears," the Obama campaign may want to keep this in mind. Rather than emphasize that Obama is not a Muslim, for instance, it may be more effective to stress that he embraced Christianity as a young man.

In 1919, Justice Oliver Wendell Holmes of the Supreme Court wrote that "the best test of truth is the power of the thought to get itself accepted in the competition of the market." Holmes erroneously assumed that ideas are more likely to spread if they are honest. Our brains do not naturally obey this admirable dictum, but by better understanding the mechanisms of memory perhaps we can move closer to Holmes' ideal. Link

Epistemology prefers to examine the value of truth, over other values such as moral impact, belief coherence, desire for social approval or emotional saliency. This emphasis goes hand-in-hand with treating memory as a passive mechanism, i.e., 'shit-in/shit-out'. The metaphor of memory as a simple storage and retrieval device does nothing to explain belief revision and why false beliefs may sometimes be justified, rational or valuable to individuals, regardless of their veritistic value.

If the extended mind literature is onto something, then any two individuals with a sufficiently reliable relationship can be considered part of a single cognitive system, just as cohesive as the intra-cranial faculties that typically define a cognitive agent. For example, married couples reliably co-represent facts and utilize each other to make decisions with an advantage over individuals solving tasks alone (Berg, et.al. 2007). Even if one is skeptical that the mind is truly extended, the benefits of group recall, problem-solving and decision-making remain.

Now suppose that the act of retrieving memories stored in ones spouse's mind can be faster, more reliable and easier than finding the information within one's own mind. This consideration runs counter to work in epistemology on testimony (see Lackey & Sosa, 2006) which suggests that the combined act of memory and perception required for testimony renders it more difficult than acts of mere memory alone. The problem with this approach is that it assumes that complexity signals difficulty.

A priori, it seems that linguistic communication between married couples is more efficient than between less familiar dyads--hence the amusement of "The Newlywed Game". Older married couples have reliable patterns of information processing and behaviour that automates particular interactions. Combining communicative ease with retrieval difficulties of one's own memory; the total effort required to request answers from one's spouse may be simpler, both experientially and computationally, than piecing together one's own fragmented recollections.

How can this be? Well, suppose that running multiple cognitive faculties in parallel can be more efficient than running a single process serially. For example, perceiving and understanding ones spouse's linguistic utterances involves many faculties working habitually and synchronistically. Contrast this with accessing a dubious past perception. The latter may be perplexing and uncertain. Even if the faculties running in parallel take longer than the serial process to produce outputs, those outputs may yield strikingly different epistemic states. Depending on the context of use, the former may have epistemic reliability that the latter do not. For example, our spouse can help us find our keys if we are absent-minded much faster than we can by-ourselves.

Also, each year cognitive tasks that were once viewed as mind-bogglingly difficult are found to utilize fairly simple heuristics. E.g. tracking a baseball requires maintaining the angle of one's head, which is a vastly simpler task than explicitly solving parabolic functions.[1]

It may turn out that testimony between intimate dyads deserves a unique epistemic approach.

[1] Of course, any task which is solved through embodiment or outsourcing then gets questioned about its cognitive status. Is the mark of the cognitive only those activities involving thought?

References:

Berg, et.al. (2007) Task Control and Cognitive Abilities of Self and Spouse in Collaboration in Middle-Aged and Older Couples. Psychology and Aging. 22(3). 420-427.

Which is better: Individual or collaborative recall?

Psychologists have found that individual recall is better than collaborative recall in typical word list recall tasks (e.g. Finlay, et.al., 2000). That is, if experimenters give participants a list of unconnected words to learn, they remember more of them if they work alone, than if paired into a group. Individuals rarely spontaneously introduce false positives when completing lists alone.

However, real life does not merely involve brute rote memory, it requires narrative construction. Real mnemic epistemic success requires the ability to both remember facts and avoid false memories. Consider a significant event, such as a marriage. When recollecting details it can be difficult to avoid adding embellishments (e.g. was it really a mustard sauce or did the steak have a pepper sauce?). However, if we convey memories with fellow event attendees, then narrative flourishes or mistakes can be picked up on and removed (or scaled back) to maintain group accuracy, (e.g. it was definitely pepper because Bob says he bit on a peppercorn and started sneezing)[1].

There is a new social false memory task which is being used to investigate collaborative reduction of false memories.

The most widely used false memory paradigm is the DRM word list (Roediger & McDermott, 1995) In this task, normal subjects are presented with lists of words with similar semantic associates (e.g. mad, fear, hate, rage, temper, fury) of a particular prototype word (e.g. anger), which is not itself studied. In subsequent tests, subjects are given lists of words that included the original list, the prototype word and unrelated words (e.g. bread). Although participants are able to separate out the semantically irrelevant words (e.g. bread), they were just as likely to recall prototype words as the actual words from the list (e.g. they claim that 'anger' was part of the original list). Not only this, but they claim to vividly recollect seeing 'anger'.

A newer false memory paradigm tests the effect of social factors in false memory creation (Roediger et.al., 2001):

Participants briefly viewed pictures of six rooms in a house and subsequently tried to recall the objects in each room... Immediately after viewing the pictures, participants were asked to remember six items from each scene. Participants took turns doing the recall with an anonymous 'other participant' who also recalled six items from the scene. The 'other participant' was actually a computer programmed to provide responses from a list of items in the photos. For three of the scenes, the computer provided the names of two items that had not appeared... Some of these false items would seem very likely to be in the target scene (high-expectancy items); other false items were less likely to be in the target scene (low-expectancy items), though not out of place...The critical recall phase occurred next. Participants were asked to remember as many items from each scene as they could. (Ross, et. al., p.86)

Collaboration on this task reduces false memory errors in both older and younger subjects (Ross et.al, 2004).

False memory experiments are an institutional type of gaslighting, deliberately tricking or manipulating other's beliefs. They provide an excellent opportunity to study how social settings can yield skewed beliefs. I'd like to do the above experiment with different power structures. For example, instead of a computer program suggesting false items, a high-status individual would suggest them. I expect that false memory acceptance would increase when a powerful person suggests them and little external verification available.

[1] We might say that pepper sauce is the least important feature of a wedding to remember, however, those sort of facts are precisely what psychologists tend to examine in word list tasks.

References

Finlay, F., Hitch, G.J., & Meudell, P.R. (2000). Mutual inhibition in collaborative recall: Evidence for a retrieval-based account. Journal of Experimental Psychology: Learning, Memory, and Cognition, 26, 1556-1567.

Roediger, H.L., III, McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, Vol. 21, 803-814.

Roediger, H. L., III. Meade, M. L., & Bergman, E. T. (2001). Social contagion of memory. Psychonomic Bulletin & Review, 8, 365-371

Ross, M., Spencer, S.J., Lindardatos, L., Lam, K.C.H., & Perunovic, M. (2004). Going Shopping and identifying landmarks: Does collaboration improve older people’s memory? Applied Cognitive Psychology, 18, 683-696.

Cognitive Scientist Rob Wilson is involved with a new collaborative project:

What Sorts of People Should There Be? is a broad, interdisciplinary, collaborative project in the humanities and social sciences that is focused on human variation, normalcy, and enhancement. By weaving together distinct philosophical, historical, and comparative threads through the establishment of a Canadian-based team of 44 researchers from 18 disciplines, this project will undertake innovative work on this topic at the interface of the humanities, biotechnology, and the social and health sciences.

Website
Blog
Syndicated livejournal Feed

One of their sub-projects is called "From Archives to Activism: Building Inclusive Communities Through Practices of Collective Memory". Contributors include: Sue Campbell, John Sutton, John Paul Himka, Lene Koch (Scandinavian eugenics), and Joanne Faulkner (working in part on the stolen generation). There will be work on trauma and memory, and on collective memory and reconciliation.

AAP 2008 Abstract

Traditional cognitivist accounts of the mind focus on an individual’s symbolic mental processing. Embodied cognition and extended mind research goes beyond the boundaries of the agent. These newer accounts promote biologically and ecologically situated cognition and endorse external epistemic artifacts as legitimate parts of an agent’s mental repertoire. Some work in decision-theory and collective memory also acknowledge the positive impact of group reasoning on individual cognition. Amongst the enthusiasm for collaborative thinking and collective memory, not much research considers the downsides to sharing cognitive resources. Although psychology warns against accidental groupthink, few write of a more insidious threat to the extended mind: cognitive sabotage. Cognitive sabotage or ‘gaslighting’ is the deliberate creation of false beliefs. Saboteurs lie or distort group information to serve selfish ends. For example, abusive husbands manipulate their wives, mothers enact Munchausen's by Proxy on their children and psychiatrists misdiagnose patients as delusional when in fact they speak the truth (Martha Mitchell Effect). Outsourcing memory and cognition may ease an agent’s informational burden, but it also increases their epistemic threats. By assuming a middle ground between cognitivism and embodied cognition, I defend a model of gaslighting that extends representational explanations of individual decision-making to an account of group cognition. I argue that the unreliable and deceptive aspects of collaborative reasoning are analogous epistemic hazards to the self-deception and flawed reasoning faced by individuals alone.

CogSci 08 Submission

Remembering Beliefs
Optimal decision-making requires us to accurately pin-point the basis of our thoughts, e.g. whether they originate from our memory or our imagination. This paper argues that the phenomenal qualities of our subjective experience provide permissible evidence to revise beliefs, particularly as it pertains to memory. I look to the source monitoring literature to reconcile circumstances where mnemic beliefs and mnemic qualia conflict. By separating the experience of remembering from biological facts of memory, unusual cases make sense, such as memory qualia without memory (e.g. déjà vu, false memories) or a failure to have memory qualia with memory (e.g. functional amnesia, unintentional plagiarism). I argue that a pragmatic, probabilistic approach to belief revision is a way to rationally incorporate information from conscious experience, whilst acknowledging its inherent difficulties as an epistemic source. I conclude with a Bayesian defense of source monitoring based on C.I. Lewis' coherence argument for memorial knowledge. PDF ( .txt )

When catching a series of unfamiliar buses to an unfamiliar part of town, we can find ourselves at the mercy of printed maps and scheduling keys. The experienced traveller senses that they should leave ample time on a first journey for unexpected contingencies, yet still can be derailed when things go wrong.

There is an interesting phenomenon whereby, if something strange happens during the first portion of the journey, it causes us to question the reliability of the rest of the information in a disproportionate way. For example, suppose we get off at a bus stop not listed in the schedule. This can be sufficiently disconcerting that we anxiously scrutinize the available information at the next bus stop to ensure we that our next bus actually stops there. Upon finding no information about our bus, we might discard our printed plans altogether and find an entirely new route based on nothing but information available at street-level. Of course, then the second bus arrives, and we miss it, because we're too busy investigating alternative routes at other bus stops.

What explains this radical departure from rational behaviour? Surely the peculiarities of our journey are due to human error rather than incorrect schedules? It seems that the emotional impact of two unexpected outcomes is so great that we diverge vehemently from a likely hypothesis in favour of a less substantiated theory.

I'd like to do more work on the role of emotions on rational decision-making. Bayesian belief revision gives us a guideline for how we should revise belief in light of evidence, but, perhaps it doesn't explain how we pick between two equivalently believable hypotheses (instrumentalism) or why we shift dramatically to an untested theory. Instead, something emotional or aesthetic comes to play. The emotions might offer impetus to make radical hypothesis changes regardless of sensible evidence analysis. Emotions create cognitive mutations; in themselves dangerous, but in conjunction with rational decision-making; lateral genius.

This is a great question, because grid cells, which are involved in processing spatial information about our surroundings, are located in a brain region that is part of a larger memory system thought to be responsible for the feeling of familiarity. After considering their function in detail, however, I think it seems more likely that a different system of neurons, place cells, plays a stronger role in providing us with the sense that a new locale is familiar—a feeling called “déjà visité.”

In any environment, the brain must keep track of the distinct locations within the surrounding area (say, at the kitchen table versus in front of the refrigerator). It also must note how these different locales relate to one another (the table is three feet to the right of the fridge, for instance). Place cells are involved in the former type of processing; each place cell corresponds to a specific location in an environment and fires when you pass through that spot.

In contrast, grid cells work in a network to produce a kind of internal coordinate system, noting information about distance and direction. These neurons do not correspond to a specific location but become active across several regularly spaced points in any setting. The geometric arrangement of these cells, relative to one another and to the external setting, ultimately helps us form a mental map of a certain environment.

Grid cells are located in the entorhinal cortex, a brain region that processes information before sending it to the hippocampus, the area where place cells are located. Because we know that place cells have a unique firing pattern for nearly every experience, it is likely that the hippocampus, and not primarily the entorhinal cortex, decides whether a location is novel or being revisited. When a strange place is experienced as familiar, it may be because the activated ensemble of place cells at that location happens to be similar to a pattern of activity that was elicited by a previous locale. Link

Is our sense of familiarity more tied to visual modalities than others? Consider the overwhelming familiarity aroused through smell. The key question here is not to consider which sense modalities yield familiarity, so much as which sense modalities yield false familiarity and why. As far as I know, I've never had an olfactory sense of déjà vu.

However, I think I have experienced déjà vu sparked by conversational content rather than visual scene. Considering the discussion above, perhaps the sense of familiarity is neurochemically triggered because I'm in some particular location and not strictly because of auditory or conceptual features of the conversation?

Deja vu might reveal yet another failure of our introspective capacity to pinpoint the causal underpinnings of our conscious experience.

Know how a whiff of certain odors can take you back in time, either to a great memory or bad one? It turns out emotion plays an even bigger role with the nose, and that your sense of smell actually can sharpen when something bad happens.

Northwestern University researchers proved the surprising connection by giving volunteers electric shocks while they sniffed novel odors.

The discovery, reported in Friday's edition of the journal Science, helps explain how our senses can steer us clear of danger. More intriguing, it could shed light on disorders such as post-traumatic stress syndrome.

"This is an incredibly unique study," said Dr. David Zald, a Vanderbilt University neuroscientist who studies how the brain handles sensory and emotional learning. "We're talking about a change in our perceptual abilities based on emotional learning."

Scientists long have known of a strong link between the sense of smell and emotion. A certain perfume or scent of baking pie, for instance, can raise memories of a long-dead loved one. Conversely, a whiff of diesel fuel might trigger a flashback for a soldier suffering PTSD.

Could an emotionally charged situation make that initial cue be perceived more strongly in the first place?

The research team recruited 12 healthy young adults to find out.

Volunteers repeatedly smelled sets of laboratory chemicals with odors distinctly different from ones in everyday life. An "oily grassy" smell is the best description that lead researcher Wen Li, a Northwestern postdoctoral fellow in neuroscience, could give.

Two of the bottles in a set contained the same substance and the third had a mirror image of it, meaning its odor normally would be indistinguishable. By chance, the volunteers correctly guessed the odd odor about one-third of the time.

Then Li gave the volunteers mild electric shocks while they smelled just the odd chemical. In later smell tests, they could correctly pick out the odd odor 70 percent of the time.

MRI scans showed the improvement was more than coincidence. There were changes in how the brain's main olfactory region stored the odor information, essentially better imprinting the shock-linked scent so it could be distinguished more quickly from a similar odor.

In other words, the brain seems to have a mechanism to sniff out threats.

That almost is certainly a survival trait evolved to help humans rapidly and subconsciously pick a dangerous odor from the sea of scents constantly surrounding us, Li said. Today, that might mean someone who has been through a kitchen fire can tell immediately if a whiff of smoke has that greasy undertone or simply comes from the fireplace.

But the MRI scans found the brain's emotional regions did not better discriminate among the different odors, Li noted. That discrepancy between brain regions is where anxiety disorders may come in. If someone's olfactory region does not distinguish a dangerous odor signal from a similar one, the brain's emotional fight-or-flight region can overreact.

Researchers say that is a theory not yet tested.

For now, Northwestern neuroscientist Jay Gottfried, the study's senior author, says the work illuminates a sense that society too often gives short shrift.

"People really dismiss the sense of smell," said Gottfried, who researches "how the brain can put together perceptions of hundreds of thousands of different smells. ... Work like this really says that the human sense of smell has much more capacity than people usually give it credit."

Link

Smell is a much under-studied faculty. It is difficult to philosophize about in part because we lack a suitably rich vocabulary to differentiate our experiences. If I'm right that a lack of olfactory conceptual apparatus is a hindrance to research, then I wonder whether our understanding of music and cognition is aided by western music theory?

Nevertheless, smell is a vital component of our episodic memory. Smells trigger emotions, mental images and thoughts that we identify with a past event. The familiarity of a particular smell gives us a lot of confidence in our memories. In my coherence theory of memory, perhaps smell should get a weighted value as a piece of evidence against other sorts of phenomenology?

Some cognitive processes are cognitively impenetrable, for example, early visual processing produces the muller-lyer perceptual illusion reliably without any impact from contrary beliefs. It simply does not matter how much one wishes to avoid experiencing the discrepancy between what we know of the lines (that they are even) and how they look (one appears longer than the other), the dissonance is unavoidable. On the other hand, the content of other cognitive processes are susceptible to manipulation. For example, one's feeling of pain can be reduced through hypnotic suggestion and our desires can be altered with new beliefs. In this paper I wish to consider a third variant of cognitive process: malleable faculties. What is a malleable faculty? A malleable faculty is one where the architecture of the faculty itself (not merely content) can be modified through the will and action of the agent.

The first malleable faculty I considered was memory as it pertains to mnemonics. The ancient greeks considered a mnemonic education essential to any citizen's intellectual development. They knew that one's intellectual capacities to remember were vastly plastic and required constant discipline to maintain high performance. There is no absolute structure that underpins everyone's memory the way there is for early vision. Some people think in pictures, others in words and some kinaesthetically*. But, more importantly, an individual can alter the architecture of their memory, either by choice or through externally generated environmental cues. Our ability to influence memory begins with attention; the way we see the world during perception. We can chose to pay attention to particular features of our world which will in turn affect what we retain at a later time. We can construct mnemonic schemes to sort incoming information into more easily retrievable chunks. If we have poor spatial or imagistic recall, we can practise to improve these areas. Like the muscles of the body, our memory is incredibly malleable. Now, of course, we will not all have infinite capacities for change. Just as men tend to have an easier time building muscle mass than women, some individuals will be innately disposed for greater mnemic potential. However, within certain biological constraints there is a vast area for work and improvement.

Another malleable faculty is introspection. Many ancient cultures have argued that through meditation we can come to know our thoughts mental states and feelings with greater clarity. The details of this process I will have to expand on at a later time.

Malleable faculties are particularly interesting from an epistemic point of view because they reveal that we can become more reliable, more knowledgeable through greater technique. Unlike static epistemic issues in perception such as blindspots, change-blindness or visual illusions, we have more control over the errors of our memories and introspection. With mental exercise we can navigate the world less prone to error. Of course, this does not mean we can avoid being tricked altogether. Memory is an inherently falliable faculty, so no amount of training can entirely eradicate error.

If memory and introspection are malleable, what sort of faculties are not open to conscious will? I argue that all the cognitively impenetrable candidates are likely immutable, e.g. early visual processing. But, perhaps also our faculty of desire and our faculty of belief. For, although we can alter the content of what we believe and what we desire, we cannot change the architecture that manipulate these propositions. Perhaps this is unfair on belief? Perhaps we can become more rational and more logical and thus more reliable at forming true beliefs or maintaining skepticism when appropriate? But, surely this is not the faculty of belief, but the faculty of reason, of thought itself? Reason may be another malleable faculty.

* We should differentiate between the way we introspect our mental states from the structure of representations underlying the phenomenology. e.g., when imagining Paris we might say, "I see the Eiffel Tower", yet have no mental imagery whatsoever. Our use of metaphor in speech (e.g. I see what you mean) is so pervasive and subtle that we must be careful before attributing significance to it. Nevertheless, there do seem to be different ways of experiencing mental states and they can involve physical differences such as emotions or bodily sensations, auditory or visual experiences.

TBC

Summary: I defend memory qualia using a Bayesian calculus to explain how the subjective feeling of remembering contributes to cognition and knowledge.


Dissertation Statement

Optimized decision-making requires us to track the origins of our mental experiences as accurately as possible. While humans are quite reliable at distinguishing, say, memories from imaginings, we are also susceptible to false memories and psychogenic amnesias. People can be manipulated into believing false childhood memories that were implanted by an experimenter, or suggested by a person in authority. In these circumstances subjects not only find fictions familiar and have strong beliefs about their veracity, but they also claim to re-experience vividly the details of their prior occurrence. Conversely, psychogenic amnesias have been reported in patients with multiple personality disorder, dissociative fugue or post-traumatic stress disorder subjects—e.g. rape victims. Individuals in these situations respond to stimuli connected to an instigating event without any familiarity or sense of connection to this past. In light of the evidence that subjective judgment is a poor guide to the true origin of our thoughts, one might wonder whether consciousness has any functional use in cognition at all. Perhaps consciousness is epiphenomenal? This is the predominant view in cognitive science.

In my dissertation I argue that consciousness is not epiphenomenal. I elucidate how the subjective experience of memory (mnemic qualia) contributes to cognition, knowledge, planning and decision-making. I begin by examining the subjective experience itself via the contributions of Aristotle, Hume, James and Russell. Hume noted that unlike imaginings, memories seem more vivid or convincing. People often justify assertions by examining the quality of the mental experience, such as the level of detail in their mental images, the degree of emotional salience or even a sense of ‘being there’. People offer factual details of events they purport to remember. Thus, memories are distinguished from imaginings partially by the way they feel and partially because of background beliefs. Inspired by the American pragmatists, I outline how the experiential and representational can be reconciled within a representational theory of mind.

I go on to integrate my philosophical defense of qualia with the source-monitoring literature from psychology. Successful source monitoring is an inferential process that requires people to examine and categorize their mental state based on qualitative features of the experience itself and coherence with other beliefs. The inferential contribution is evident in cases of ‘déjà vu’, where we experience the feeling of memory but rationalize that we are not remembering.

The coherence view in the source monitoring literature in psychology is supported by a Bayesian account of belief. This view is that the congruence between independently generated beliefs can raise the probability of what is remembered to the level of practical certainty in a way analogous to that in which agreement of independently given testimonies can eventually convince us that what is being testified is true. The theory works on the basis that there is initial credibility (i.e. a non-zero prior probability) for the memory in question. Coherence increases the posterior probability that x occurred with the number of consistent beliefs. However, the coherence of independent items of evidence has no impact on the probability of a conclusion unless each item has some credibility of its own; for example, a person with poor vision would be unwise to treat mental images from an event as seriously as their auditory memories.

The Bayesian account explains how normal memories are successfully segregated from other mental phenomena. But, perhaps more impressively, it sheds light on circumstances when source-monitoring fails. Because we must already begin with a degree of belief in a particular memory, Bayesianism explains why psychogenic amnesia patients have no capacity to revise beliefs. It also shows how individuals who are unusually gifted at creating cross-modal phenomenology are particularly prone to false memories. Individuals who are fantasy-prone, or hypnotically suggestible are wise to remain skeptical of their qualia, because coherent subjective experiences are too easily constructed by their imaginations.

I conclude that regardless of the functional underpinnings of our cognitive architecture, consciousness impacts our reasoning and this is rationally explained by combining the empirically informed source-monitoring literature and a Bayesian probability calculus.

The term 'qualia' was coined by C.I. Lewis in 1929 in Mind and the World Order. In 1946, in An Analysis of Knowledge and Valuation, Lewis defended a Bayesian account of memorial knowledge. It seems that my entire dissertation is being inspired by a philosopher I know almost nothing about.

Today I have sought him out.

While many saw Lewis as kin to the logical empiricists, he was never truly comfortable in such company because he declined to divorce experience from cognition. Positivism rejected value as lacking cognitive significance, also rejecting the analysis of experience in favor of physicalism. Both rejections struck him as regrettable. Indeed his growing awareness of the pragmatic tradition led him in the opposite direction. For Lewis, it is only within experience that anything can have significance for anything, and thus he came to see value as a way of representing the significance of knowledge for future conduct. These convictions led him to reflect on the differences between pragmatism and positivism, and on the cognitive structure of value experiences.
Link

I have great fondness for the American pragmatists and didn't realize how Lewis fit into this tradition. It seems he was also excited by the role of subjective experience on cognition.

In my searches, I found a memorial Lewis wrote for the Journal of Philosophy in 1954 (Vol. 51) for George Santayana--a man of letters famous for the quote: "Those who cannot remember the past are condemned to repeat it". Here is a section from the memorial:

The external impression was somewhat striking; and it remains vivid with me. I can still see him as he came through that gate out there on Quincy Street; a taller than average figure, erect and well set up, walking with easy gait like that of a man who has sometime learned to march. He appeared observant of whatever went on about him, but not engaged with it-a little aloof perhaps, as if his thoughts were elsewhere. He wore a longish military cape, instead of an overcoat, coming over from his rooms, and I can see him as he swung it off at the door. The complexion was a little darker than the average, indicative of the Spanish strain in his inheritance; and the eyes at once drew notice. The features and general presence were such as I can only suggest by the word "aristocratic."(p.29)

I love the nested sorts of remembering involved in a memorial of a man famous for valuing memory. I am intrigued by Lewis' use of the word 'vivid' and the precise description he provides of the professor. The description suggests that Lewis is not remembering a single event, but has averaged out a set of experiences to produce a distilled essence of experience.

It makes me think of the usual differentiation of episodic memory into either abstract/conceptual or event specific knowledge (ESK). Abstract/conceptual episodic memory involves explicit memory for facts about events in a person's life, e.g. "when I was at high school I studied chemistry and once I performed a perfect titration". On the other hand, ESK involves near-sensory experiences (E.g. mental imagery, smells, tastes), emotions (joy, fear, sorrow, sense of significance). Lewis' recollection seems to incorporate both abstract/conceptual episodic memory and ESK. That is, he constructs a near-sensory recollection fabricated from many exposures.

We all do this frequently, e.g., when we imagine eating a lox and cream cheese bagel, we recollect the feelings from many instances.

Society for Philosophy and Psychology Submission

Title: Remembering Beliefs
Abstract:
Optimal decision-making requires us to accurately introspect the origins of our mental experiences. In this paper I examine how different types of remembering impacts belief. Remembering can be implicit—either representational or procedural—and remembering can be explicit—either semantic or episodic. The minimal conditions for remembering are a causal connection to the learning event and the retention and subsequent impact of this learnt material on behavior, regardless of our conscious awareness or attribution. The minimal conditions for recollection require remembering, belief and mnemic qualia. Whenever we have conscious influence over our memory attributions, it is in our interests to efficiently source their origins. I look to the source-monitoring literature to reconcile circumstances where beliefs and qualia conflict. By separating the experience of remembering from biological facts of memory, unusual cases make sense, such as memory qualia without memory (e.g. déjà vu, false memories) or a failure to have memory qualia with memory (e.g. functional amnesia, unintentional plagiarism). I conclude with a Bayesian defense of source-monitoring based on C.I. Lewis' coherence argument for memorial knowledge.

“The day of [my sister's] birth is my earliest memory, or my earliest datable memory, anyway. I distinctly remember playing with a bit of plasticine in the kitchen while my father rushed in and out of the room, hurrying backwards and forwards to my mother, who was giving birth in their bedroom. I know I didn't invent this memory because I checked the details later with my mother. I also have a vivid mental picture of walking into their bedroom a little while later, hand in hand with my father, and seeing my mother lying in bed in her nightdress next to my beaming sister, who is stark naked with a full head of hair and looks about five years old. Although I clearly pasted together this bizarre false memory out of bits of hearsay when I was a child, it is so vivid that it still comes to mind if I ever think about Di being born.”

From J.K. Rowling's biography.

Above is a lovely example of how an author examines her own memories. There are two good components here:

1) Her 'earliest memory' (dated at 23 months) may be an accurate rendition of facts from her past, but is it truly a memory? Details 'remembered' from two years of age are easily implanted by parents eager to create a shared narrative with their adult children. Individual memories can be created by discussion within a group to create and enhance collective memory. In this case, the birth of Rowling's younger sister is an important and bonding event for the entire family.

Compare this example with your own 'memory' of the attacks on the world trade center. How well do you remember clearly your own actual experiences as they unfolded at the time? How sure are you that you haven't altered your narrative to fit in with the social group you are communicating using details informed via testimony and heresay over personal experience?

There has been an effort in the 20th century to define what counts as a memory more rigorously. One of Martin & Deutscher's (1966) suggestions is a causal criterion for remembering.

Causal Criterion

"to remember an event, a person must not only represent and have experienced it, but also his experience of it must have been operative in producing a state or successive states in him finally operative in producing his representation." (p. 173) They explain:

"A person has an apparent recollection of something from early childhood, and wonders whether he really remembers it. His parents may tell him that what he describes did happen, and that he witnessed it, but the discussion of whether he remembers it still goes on. They wonder whether his witnessing of the event has any connection with his now giving the story or whether his description can be completely explained by what he heard later." (p.176) [my italics]

The point for Rowling is that even though she may have been in the kitchen playing with plasticine when her sister was born, it is less clear that she can actually remember the event when she recounts it. This is even more questionable when we look to the second component of the memory.

2) Rowling explains that she has a vivid false memory of her newborn sister looking like a five year old. She knows this must be false because of its absurdity, nevertheless, her experience of it very strong. It is precisely this sort of experience that I'm investigating in my PhD. One of the ideas I'm studying is the individual differences in false memory suceptibility. If Rowling has a powerful faculty of mental imagery, then--based on the causal criterion--she should be even more careful about any recollections, even when facts support her stories.

I'd like to do an experiment where I study a statistically significant set of autobiographies and then I run false memory tasks on the protagonist. It would be interesting to compare the way people report on their memories compared with their actual performance in a laboratory setting.

Source

Martin. C.B. & Deutscher M. (1966) Remembering. The Philosophical Review. 75(2). 161-196

This entry on imagination appears in the Encyclopedia of American Philosophy

Imagination

Imagination is a capacity of internal visualization, concept creation and manipulation not directly dependent upon sensation. Imagination is associated with a range of phenomena: mental imagery, fancy, inventiveness, insight, counterfactual reasoning, pretence, simulation and conceivability. Products of the imagination are sometimes considered false or fantastical, e.g. the phrase, ‘I must have imagined it’ is applied to explain a mistake in conversation. The term ‘imagine’ is also used in countless idiomatic ways that do not imply any use of an imaginative faculty; for example, a person might exclaim ‘imagine that’ to an unusual news item.

In the history of western philosophy most connotations of the term ‘imagination’ are a response to the notion of mental imagery and imagistic representation. Philosophers ask how mental ‘pictures’ could be ‘in the head’ and how those ‘pictures’ can have intentionality. The association of imagination with inventiveness has yielded epistemological concern for imagined ideas, including what kind of knowledge stems from the imagination and whether conceivability impacts possibility. Contemporary cognitive science is focused on the cognitive architecture underlying imaginative thought and suggests connections between imagination, counterfactual reasoning and understanding other people’s mental states. This approach has impacted broader philosophical areas such as ethics, where the imagination plays a role in invoking moral responsibility through simulation, role-play and empathy. Non-visual sense modalities (e.g. hearing) have received much less attention in the imagination literature (Currie and Ravenscroft, 2003). Because of the range of uses of the term ‘imagination’ it is illuminating to look at the history of the faculty of mental imagery.
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...During sleep, the reactivated memories of real-time experiences are processed within the brain at a higher rate of speed. That rate can be as much as six or seven times faster, and is described as “thought speed.”

Memory stores patterns of activity in modular form in the brain’s cortex. Different modules in the cortex process different kinds of information - sounds, sights, tastes, smells, etc. The cortex sends these networks of activity to a region called the hippocampus. The hippocampus then creates and assigns a tag, a kind of temporary bar code, that is unique to every memory and sends that signal back to the cortex.

Each module in the cortex uses the tag to retrieve its own part of the activity. A memory of having lunch, for example, would involve a number of modules, each of which might record where the diner sat, what was served, the noise level in the restaurant or the financial transaction to pay for the meal.

But while an actual dining experience might have taken up an hour of actual time, replaying the memory of it would only take 8 to 10 minutes. The reason... is that the speed of the consolidation process isn’t constrained by the real world physical laws that regulate activity in time and space.
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From HERE

What is most interesting about this research from my perspective is the relevance for source-monitoring. Source-monitoring refers to how we determine whether our memories are of a real event, a dream or just a fiction. One of the ways we evaluate memories is to bring to bear information from different modalities. E.g. If we cannot draw a memory that is tactile for an intimate experience, then it is evidence that we only dreamt of the encounter. It is incredible to see experimental evidence of memories forming that parallels theoretical work done in cognitive psychology on mental experiences.

In Analysis of Mind (Lecture IV), Bertand Russell uses the perception and recognition of peat smoke to explain mnemic phenomena. He notes that identifying a current perception as 'peat smoke' requires not merely the proximal cause, but also the recollection of smelling peat smoke in the past.

"...you smell peat-smoke, and you recall some occasion when you smelt it before. The cause of your recollection, so far as hitherto observable phenomena are concerned, consists both of the peat smoke (present stimulus) and of the former occasion (past experience)."

Aristotle also thought we brought to mind our previous experiences during remembering. He believed that a past encounter "always serves as the past object of awareness not... merely as a past cause" (Sorabji, p.x) and he used this to defend the role of mental imagery in his theory of mind.

I disagree with Russell and Aristotle. I do not have to recall a previous event of smelling peat smoke in order to recognise the current smell as peat smoke. Recognition requires no overt conscious recollection. Presumably Pavlov's dog recognised the food bell without bringing to mind previous experiences of the bell and subsequent food. Similarly, I can forget the event where I met a person, yet remember them clearly upon meeting them again.

Richard Sorabji makes a related point that "when one remembers a scene, one may be likely to remember it from one's previous point of view, but this falls short of remembering the actual viewing." (Aristotle on Memory, p.xi) Norman Malcolm states that when remembering a plane crash, we need not remember seeing the crash itself. (Memory, p.24)

Nevertheless, I am sympathetic to Russell's idea that recognition requires the past experiences to cause the reaction to the present stimulus.

I have my own experience in Montreal to explore this further. In Montreal 18-Mar-05, I alighted from a train and a familiar smell filled my nostrils. Yet, no matter how distinctive the odour, I could not remember it as smell x. The x was missing. As I walked towards the exit my partner was able to identity the smell as sawdust. Immediately I knew that he was right and the phenomenal experience now fell under a description.

I take it that my initial experience was contentful, though nonconceptual, and fits Gareth Evan's theory of demonstrative reference. That is, I could refer to that smell x, without defining exactly what 'x' referred to. On the other hand, perhaps my experience was better evidence of conceptual contents that do not fall under a description? It would appear that either a) we do not need a description to have concepts b) my recollection of sawdust was nonconceptual.

There can be no doubt that when I smelt the familiar smell, I was bringing to mind a memory of a prior perceptual (in this case olfactory) experience and matching it with the smell I was now experiencing. But, how was I able to grasp this memorial content without attributing to it the 'sawdust' nature of it?

Would it matter if I continued to refer to this smell in relational terms and never again regained the ability to communicate the contents of experience conceptually with my peers? Surely this is what a dog does when they can recognise scent trails? Although it may not matter if my recognitional ability remains nonconceptual. I guess the interesting question is how this non-conceptual memory becomes conceptual and how it changes the underlying representation in the mind.

References

Evans, G. Demonstrative Identification
Malcolm, N. Memory & Mind
Russell, B. Analysis of Mind
Sorabji, R. Aristotle on Memory

Brain Stains: Traumatic therapies can have long-lasting effects on mental health
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Recovered-memory therapy relies fundamentally on the notion that some memories are so unspeakable that the mind represses them to protect itself. Decades of research conducted by neurobiologist James L. McGaugh of U.C.I. suggest, however, just the opposite—that one key function of memories is to recall threatening situations so that they can be avoided in the future. Human experiments by McGaugh and neurobiologist Larry Cahill, also at U.C.I., have shown that emotional arousal tends to make memories stronger. Likewise, when animals receive injections of the stress hormone epinephrine (also known as adrenaline), they sail through memory tests. Not only do these experiments run counter to the notion that traumatic memories are repressed routinely, but they also may elucidate why patients such as Storm, whose therapy focused on “guided imagery” and enactments of traumatic scenes, report that these experiences have become fixtures in their memories.
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The idea that emotionally laden memories can be induced in a clinical setting dates back to experiments conducted nearly a century ago. Famed behaviorist James B. Watson “conditioned” an 11-month-old infant, known in every introductory psychology text as Little Albert, to fear a white rat. The infant showed no sign of fear toward the furry creature in the first session, but after the white rat was paired with a very loud noise, Albert responded with tears. Later, Albert cried when he was presented with a variety of stimuli that resembled the rat. This early case suggested that a therapist (or experimental psychologist, in this case) could easily create emotional associations and that these mental connections could be so powerful that they generalized to similar stimuli. In the case of Little Albert, the memories were “implicit”—that is, not consciously recalled—but Watson’s findings remind us that powerful emotional memories can be enduring.

In Storm’s case, a technique called abreactive therapy helped to create these emotional associations. Storm was told that abreactions were total-body “flashback” reactions that would enable her to relive the traumatic events in her life, complete with the sounds, smells, sights and tactile experiences of these events. Olson instructed Storm to allow her alters to come forward and share their participation in unthinkable acts such as eating babies. For Storm, this therapy was physically, mentally and emotionally grueling. Years later the conditioned associations remain strong. Storm is plagued not only by her explicit memories of the disturbing scenes brought to life in her therapist’s office but also by implicit memories that provoke reflexive physical reactions.
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Neural Restructuring
Decades of behavioral neuroscience experiments using animal models have consistently suggested that trauma and fear can change the architecture of the brain. For example, neuro­scientist Bruce McEwen’s group at the Rocke­feller University has shown that chronic stress alters neuronal complexity in three key areas: the medial prefrontal cortex (involved in working memory and executive function), the hippocampus (involved in learning, memory and emotional processing) and the amygdala (involved in fear and intense emotions).

McEwen found that chronic stress reduces length and branching of dendrites in the brain’s medial prefrontal cortex by about 20 percent. This reduction is associated with an impaired ability to shift attention while learning new tasks. In contrast, neurons in the amygdala grow in response to fear. The functions of the brain areas that are affected by fear and stress in animal studies are closely aligned with the symptoms exhibited by recovered-memory patients. Compromised functioning of the prefrontal cortex may be associated with a patient’s inability to distinguish reality from fiction, whereas growth of neurons in the amygdala may lead to hypervigilance and suspiciousness. Animal research also suggests that once therapy sessions cease, compromised prefrontal cortex functioning may diminish the ability to inhibit fearful memories.
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Although research evidence is lacking, some patients might find relief through antianxiety medications that mitigate intense emotional responses. Others have been helped by behavioral conditioning designed to extinguish alters by ignoring them. These therapies have not been systematically assessed for MPD-DID in large-scale studies, however. McEwen’s studies of animals exposed to chronic stress suggest that brain alterations, though physical in nature, could be reversed by medications or by living in a stress-free, enriched environment.
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Continuing my train of thought from the previous post: emotions play a big role in the formation of memory and our judgment that a particular mental experience is a memory. Recent research supports Hume's thesis that imaginings and memories are differentiated by their vivacity. Where vivacity refers to not merely the perceptual qualities of our mental images, but the emotions, feelings and sensations of an actual experience. If we affect people's emotional connection with a particular imagining, we can increase the likelihood that they will confuse it for a memory. Conversely, if we can reduce the level of emotions in mental experiences, we may be able to reduce source-monitoring issues.

Both extensive psychological research and personal experiences confirm that events that happen during heightened states of emotion such as fear, anger and joy are far more memorable than less dramatic occurrences. In a report this week in "Cell", Johns Hopkins researchers and their collaborators at Cold Spring Harbor and New York University have identified the likely biological basis for this: a hormone released during emotional arousal "primes" nerve cells to remember events by increasing their chemical sensitivity at sites where nerves rewire to form new memory circuits.
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This research suggests that emotions affect the ease of encoding. Of course we need to keep in mind that 'more memorable' does not necessarily mean 'remembered better', e.g. if a person deliberately avoids thinking about an event that occurred under emotional duress, they can affect subsequent retrieval.

Nevertheless, the research findings tie in nicely with my current thinking about the importance of emotion for memory. One of my key claims is that we distinguish memories from imaginings by their vivacity. Whilst most philosophers interpret vivacity as being about visual perception, I believe it is essentially an emotional salience. We furnish our memories with perceptual and conceptual details, but the conviction that they are memories is a feeling.

Roediger, Dudai, Fitzpatrick, (2007) Science of Memory: Concepts. Oxford

In this volume, memory researchers from psychology and the physical sciences undertake conceptual analysis on sixteen ideas central to the study of memory. For example, learning, plasticity, encoding, retrieval, remembering and forgetting. Many frequently discussed concepts were left out for a variety of reasons including because they describe methods (e.g. conditioning, priming), anatomical structures (e.g.amygdala) experimental results (false memories), or are derivative of other concepts studied (e.g.amnesia). The editors stress that they tried to include concepts that were not merely descriptive, but also explanatory. Questions they sought answers to include: "what (exactly) do you mean when you use the term X", "what is X?" and "what does X do?". This last question seeks the explanatory answer of the term within the theory or framework of memory research.
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I argue that the study of memory is the study of how experiences are processed such that they have a future effect on thought and behaviour. Thus, memory research is interested in a) the faculties of memory, b) the representations created within the memory faculty and c) the actions or functions of the memory faculty regarding these representations. Faculty is defined a functionally distinct cognitive system. Thus, we have various memory faculties such as procedural , declarative, episodic etc... Each faculty deserves its own investigation and results from one may have little to do with one another. For example, perhaps procedural memory will turn out to have no representations as such, but merely the architecture to learn and repeat skilled behaviour? I am open to a theory of computational architecture which benefits from the research done on connectionist networks and representational systems. Our minds may include a variety of systems all working together. Use of the word 'memory' in any formal discussion should be carefully explained to keep research ideas distinct.

Neuroscientists have discovered that long-term memories are not etched in a "clay tablet"-like stable form as once thought. The process is much more dynamic, involving a miniature molecular machine that must run constantly to keep memories going, and jamming this machine briefly can erase long-term memories.
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In other words, long-term memory is not a one-time inscription on the nerve network, but an ongoing process which the brain must continuously fuel and maintain and these findings raise the possibility of developing a "memory eraser".

As a memory researcher, it is important to understand what a 'memory' refers to in order to contemplate this article. That is, work done on rats showing that learned responses can be unlearned using a drug may have no impact on our knowledge of 'memories', aka recollections of events in humans. See my post about this issue HERE.

This post was written using notes taken during Pamela Lyon's talk at ASCS '07.

INTRODUCTION

Cognitive science must have an answer for two key questions: what is cognition, and what kinds of creatures or systems are cognitive? Descartes argued that only humans were cognitive agents due to their rationality, reflectiveness and perhaps creativity. In the 20th century, behaviourism showed that much of animal behaviour--including human behaviour--could be explained without recourse to mentalizing of any kind, simply by examining stimulus and response. The cognitive revolution in the 1960s showed that even animals such as rats must use mental maps and representations of the external world to make decisions. At the same time computers were being programmed to undertake a multitude of tasks often considered cognitive (e.g. play chess, interpret sentences (e.g. Eliza). These two research paths suggested that perhaps cognition was not the unique faculty of humans at all?

Nevertheless, solving the puzzle of exactly what is cognition has remained. It is within this context that the study of bacterial cognition is interesting. Bacteria--and by extension unicellular eukarotes--have long been considered to simple, too reactive and too determined to be a member of the cognitive gang. However, Pamela Lyon argues that this exclusion is unwarranted. She suggests that bacteria are sensitive, communicative and decisive organisms and bacterial responses are more flexible, complex and adaptable than generally believed. In terms of re-defining cognition, Lyon argues that behaviour at the microbial level is precisely what must be understood in order to comprehend how more complex and specialized forms evolved and now function. Lyon claims that cognition is part of basic biological function, like respiration.[1] A good way to examine this is through a case study of myxococus xanthus (MX).

Case study - myxococcus xanthus

M.xanthus is a gram negative rod-shaped proteobacteria (picks up a stain on a test). M.xanthus dwells in soil and organic waste. M.xanthus is predatory, territorial and highly social. Almost no stage of its life cycle is solitary. The demands of cooperative living and navigating an epistemically polluted environment significantly shape its behaviour. M.xanthus dwells in a challenging, constantly fluctuating, informationally rich environment that is teeming with predators as well as prey; e.g. one gram of soil is estimated to habour up to 10 billion microbes of possibly thousands of species, which live alongside eukaryotic organisms (plant and animal). M.xanthus is well-equipped to cope with this environment.

There are three arguments against bacterial cognition, 1) Flexibility 2) Complexity and 3) Distilty

FLEXIBILITY

Lay-people generally assume that bacterial responses are inflexible and unmodifiable. That is, bacterial behaviour presumed to be rigidly determined by the organism’s genetic endowment and the nature of the stimulus. It is also thought that Bacterial behaviour does not require memory, is not sensitive to context or does not involve selection among alternative actions.

However, decision-making in bacteria has been known for over 30 years. Responses integrating multiple or conflicting stimuli are not always additive or linear. Bacteria have a huge repertoire of responses including: Swarming motility, ‘Wolf pack’ hunting and deceptive signaling, e.g. M.xanthus lures E. coli within killing range.

Bacteria sense features of their environment via two types of signal transduction system: 1-component and 2-component systems. 2CSTs have separate protein sensor and response regulators. The total number of ST systems has been likened to ‘bacterial IQ’ and the predominant type (1CST or 2CST) as reflecting ‘introversion’ or ‘extroversion’. To give an idea of how complicated bacteria are, E.coli shown to have 30 different sensors and 34 response regulators of differing activities and reaction speed—and that’s just its 2CSTs. The number of STs in M.xantus is unknown. However, due to complex lifestyle it is estimated to have 5 times as many as E. coli.

These findings suggest that bacterial behaviour is highly flexible and involves complicated decision-making.

COMPLEXITY

Bacteria are thought to be very simple creatures, without a sufficiently complex nervous system to constitute a cognitive agent. They are not supposed to have a life-cycle or development. However, not only are bacteria sufficently complex as individuals, they also have communal living arrangements with incredible emergent complexity (e.g.colonies, swarms, multispecies biofilms). Not only this, but the information processing systems that generate bacterial behaviour share mechanistic similiarities (not simply conceptual similiarities) with those that generate human behaviour.

Biofilms

A biofilm is a highly structured living arrangement with 100s of species of bacteria. An analogy can be made between the biofilm and a city because within the biofilm there is division of labour and mutual living (i.e. bacteria live off each others waste-products and productions.) The biofilm allows access to resources that individuals cannot obtain or use. The biofilm provides protection against predators, optimized survival and reproduction.




Catheter biofilm

Bacterial development

Development in bacteria refers to changes to cell morphology or function. M.xanthus forms fruiting bodies similar to slime mold. This aggregation is like ‘great herd migrations’. In the formation of the fruiting bodies, 10-20% will form spores and survive and 80% commit suicide (autolysis) to provide nutrients for the group. A small percentage become ‘sentries’ on the perimeter. Incompetent cells are provided with proteins by conspecifics to make them competent. Cheater mutants never prosper in these ecosystems/set-up. Occasionally there is the arrival of very efficient cooperators who are very good at providing proteins (like a messiah bacteria)


Under starvation conditions, m.xanthus undergoes a magnificent developmental process in which roughly 100,000 individual cells aggregate to form a structure called the fruiting body over the course of several hours.


M.xanthus fruiting body

These examples show that bacteria are complex, social creatures.

DISTALITY

'Distality' is a concept most easily understood by contrast to proximity. The term is used to investigate the distance between objects, events or properties that are significant for the perceiver and the behavioural response. Bacterial responses are generally thought to be proximal in three ways. a) they are within direct contact of stimulus physically b) they have a small amount of mechanistic complexity involved in processing the stimulus information (aka Dennett's unity position on intentionality) and c) temporally continuous (i.e. no memory), lack of decoupling mechanisms.

Although I don't have detailed notes for all aspects of the distality argument, an amazing example of a distal capacity of bacteria is their ability to communicate. Bacteria have a chemical messengering system called 'Quorum Sensing' (QS) that they use in the biofilm. There are intraspecies as well as interspecies quorum sensing (called bacterial ‘Esperanto’). There are at least five different quorum sensing systems known so far. Some bacterial strains are known to use three systems. Quorum sensing molecules are proximal indicators of distal states of affairs (e.g. the presence of (non) conspecifics).

Another distal example involves swarms of M.xanthus have been found to migrate non-randomly toward glass beads from a distance of 10 body lengths.[2]

It is also unclear exactly why distality is a necessary feature of cognition, rather than one of the properties that certain forms of cognition feature.

CONCLUSION

This post has a small fraction of information about bacterial cognition. Even though bacteria may not be aware, they certainly have complex behaviour and decision-making worth examining. Bacteria perceive, remember, problem-solve, learn and communicate. Understanding how they make group and individual decisions may contribute importantly to our understanding of cognition across many species including humans.

[1] This reminds me of Searle's argument that consciousness must be understood as a fundamentally biological output, just as lactose cannot come from equations mimicking function, thought cannot come from computation alone.

[2] An incredible article on bacterial directed movement towards objects can be found HERE.

THE FIRST PART OF PASSIONS IN GENERAL:
and occasionally of the universal nature of man.

The 26th Article

...It is here to be observed that all the same things which the soul perceives by intercourse with the nerves, may also be represented to it by the accidental course of the spirits. And [there is] no difference between them but this, that the impressions which come from the brain by the nerves, are usually more lively, and manifest than those the spirits excite there, which made me say in the one and twentieth Article, that these are only as the shadow, and representation of these. It is also to be noted, that it sometimes falls out, this picture is so like the thing it represents, that it is possible to be deceived concerning the apprehensions attributed to whose objects without us, or those referred to any parts of our body...

Descartes suggests that imagined ideas (perceived by the soul) are less lively than those produced from the senses (impressions from the brain informed by the nerves). However, he acknowledges that sometimes our mental images (or representations) are sufficiently vivid to deceive us as to their origins. Hume also had this idea when he spoke of the 'force and liveliness' of memories compared with imaginings. It is amazing how many ideas in philosophy get re-fashioned with new metaphors every 100 years.

Descartes describes ideas as shadows of the original object that they represent. He described mental activities as the motion of spirits. Today cognitive science describes mental activities as algorithms, programs, or emergent properties of computational networks.

Each age struggles to understand the mechanism of consciousness within the scientific and cultural framework of the time. Yet, how much progress do we make by describing continually mysterious processes with familiar metaphors? Do they actually advance our understanding or simply soothe our curiosities for a time?

Conway & Fthenaki (2000) suggest that abstract knowledge (about a lifetime period or general events) provides a context for the retrieval of event-specific knowledge which, in turn, is "near-sensory experience"... Knowledge at higher, more abstract levels can be used to access knowledge at more specific levels. Autobiographical memory is considered as a superordinate memory system that takes input from subordinate memory systems and binds together patterns of activation from across those lower order memory systems into mental representations that are experienced as "autobiographical memory". Because any of the subordinate systems can break down, it can lead to a loss of access to autobiographical memory knowledge. Loss of the knowledge itself is predicted to occur less frequently, and to arise from diseases causing widespread damage and degeneration, such as the dementias.

There are two kinds of transient amnesia: 1) psychogenic amnesia and 2) organic amnesia

Psychogenic

Depression

Psychogenic amnesia ecompasses memory impairment in depression and extreme cases, psychodementia. It can entail transient or discrete episodes of memory loss. Depressed people can have difficulties articulating detailed (vivid) autobiographical memories. Instead they make generalizations, e.g. remembering that "my father liked taking long walks in the park" instead of "I remember one time my father walked in the park during fall and kicked a big pile of leaves". They struggle to re-experience any particular instance when the generalized behaviour is discussed. A depressed person might remember (as in retain storage of) events of a particular occasion, but the capacity to introspect this is temporarily cut-off with the experience of depression.

Violent & Emotional Experiences

Interestingly 23%-47% of people convicted of homicide claim amnesia for the killing. At a 3 year follow-up 33% had complete return of memory, 26% partial return and 41% no return of memory. Violent crime, extreme emotional arousal and alcohol intoxication impair recall in both perpetrators, victims and eyewitnesses of crime. Amnesia occurs in four main types of circumstance: crimes of passion, psychosis/delusional individuals, alcohol abuse and intoxication and brain disorder/automatism. The first two are psychogenic, the latter two are organic.

Organic amnesias

Epileptic automatisms affect memory formation, so no later recall is likely. Hypoglycaemic people have got amnesia after killing a friend without motivation. Sleepwalking or somnambulism also produces violent attacks with amnesia. None of the organic sources of amnesia are likely to produce memories that can be accessed later as the underlying condition affects hippocampal function.

Sources:

Conway & Fthenaki (2000) Disruption and losss of autobiographical memory. In L. Cermak (ed.), Handbook of Neuropsychology, 2nd edn, Vol 2 (pp.281-312). Amsterdam: Elsevier Science.

Kopelman, M.D. (2002) Psychogenic Amnesia. In A.D. Baddeley, M.D. Kopelman and B.A. Wilson (ed.), The Handbook of Memory Disorders, Ch.21. John Wiley & Sons, Ltd.

AAP Abstract: What is it like to remember? It depends on what is meant by the term ‘remember’. Aristotle divided memory into two distinct varieties: remembering and recollecting. He argued that remembering was a capacity of most living creatures. On the other hand, recollection is a conscious act known only in humans. This important distinction pre-dates a similar division in cognitive science between implicit knowledge or skills and the explicit capacity to recall facts or recreate past experiences. Russell argued that all acts of ‘remembering x’ require the ‘belief that x occurred’. Martin & Deutscher (M&D) denied Russell’s hypothesis. I argue that M&D are right in the sense that remembering does not require an occurrent belief. But, they are wrong about Russell for two reasons: 1) Russell is referring to recollection, not just remembering. This subjective feeling, the qualia of memory, essentially involves an occurrent belief that it is a representation of the past. 2) Even if Russell was referring to just remembering, this capacity requires a functional notion of belief or knowledge. By separating the experience of recollection from biological facts of memory, unusual cases make sense, such as memory qualia without memory (false memories) or a failure to have memory qualia with memory (e.g. M&D examples).

I first encountered Richard Semon through Daniel Schactor's book Searching for Memory. I was intrigued by Semon's theory of resonance and the concept of the engram.

Schacter was inspired as a graduate student to investigate Semon after reading Bertrand Russell, but he doesn't give a precise reference. (This happens quite a lot when psychologists mention philosophical ideas. You would think that bibliographical detail was important regardless of discipline.)

Nevertheless, today I was reading Russell and found some accolades to Semon, calling him "interesting and ingenious". During this writing, Russell defines memory as the key to understanding experience. This I find particularly interesting as it contrasts with A.J. Ayer who considers memory less philosophically foundational than perception. When modern philosophers discuss experience they seem to be echoing Ayer, not Russell. That is, the term 'experience' and perception' are used interchangeably. Russell did not think of them this way. He argues that if perception has no effect on subsquent behaviour, then we have not had an experience. Russell's notion of experience seems similiar to that found in information theory.

It is only mnemic phenomena that embody experience. We may say that an animal "experiences" an occurrence when this occurrence modifies the animal's subsequent behaviour, i.e. when it is the mnemic portion of the cause of future occurrences in the animal's life. The burnt child that fears the fire has "experienced" the fire, whereas a stick that has been thrown on and taken off again has not "experienced" anything, since it offers no more resistance than before to being thrown on. The essence of "experience" is the modification of behaviour produced by what is experienced. We might, in fact, define one chain of experience, or one biography, as a series of occurrences linked by mnemic causation. I think it is this characteristic, more than any other, that distinguishes sciences dealing with living organisms from physics. [italics added]

The best writer on mnemic phenomena known to me is Richard Semon, the fundamental part of whose theory I shall endeavour to summarize before going further: ( Read more... )

Bertrand Russell, The Analysis of Mind, Lecture IV. Influence of Past History on Present Occurrences in Living Organisms

The way we perceive objects at a distance is different to the way we perceive objects close-up. We learn quickly to expect less detail for distant objects and revise our epistemic criteria as we get nearer to them. This capacity to adapt the strength of our beliefs based on the awareness of distance does not work as well for time. That is, when we look into our distant past we are not as reliable at recognising how poor our information is. Part of this is because our imagination is very good at seamlessly filling in data to match our desires or expectations. We are less good at acknowledging when such an operation has occurred. In the same way the blind spot in the eye makes up a visual story that corresponds to the surrounding environment effortless and without our awareness, our imaginations make up coherent detail from a fictional past to correspond to whisps of real memory tucked away.

In the study of episodic memory, while there is acknowledgement that childhood memories are particularly susceptible to alteration, there is also a sense that their essence is more secure, perhaps because they have been more frequently accessed, thus reinforced more than recent events. While it is true that the event x may become more vivid or more stable over time, it does so at the cost of accuracy or relevance to the originating event. Just like playing chinese whispers with a group, our memories become a little less accurate with each re-telling, even if that is simply recalling the event to ourselves. The tyranny of time combined with the creative manipulation of the imagination contributes to a crippling situation for us to monitor our beliefs based on consicous awareness of their vivacity.

But, importantly, this epistemic problem becomes less severe the closer we are to the historical event. That is, in the same way objects become more detailed the closer they get, we recall recent events in more accurate detail than those in the past.

Now we need tools to evaluate our memories. We need a device which helps carve our conscious experience into 'imagined' and 'remembered'. This device would help us understand which parts of events do seem to stick (perhaps the venue, rough numbers of people, colours?) and which tend to fade and be recreated with the clever brush of the imagination. This tool would also track how the sticking and fading components shifted and fell away depending on the distance we had now travelled from the originating event.

Memorizing a series of facts is one thing, understanding the big picture is quite another. Now a new study demonstrates that relational memory--the ability to make logical "big picture" inferences from disparate pieces of information--is dependent on taking a break from studies and learning, and even more important, getting a good night's sleep.( Read more... )
"This strongly implies that sleep is actively engaged in the cognitive processing of our memories," notes Ellenbogen. "Knowledge appears to expand both over time and with sleep."

Concludes Walker, "These findings point to an important benefit [of sleep] that we had not previously considered. Sleep not only strengthens a person's individual memories, it appears to actually knit them together and help realize how they are associated with one another. And this may, in fact, turn out to be the primary goal of sleep: You go to bed with pieces of the memory puzzle, and awaken with the jigsaw completed."

From here

It's good to see some empirical data on this intuitive result. So many people report problem-solving benefits from a good night sleep that these results are not really a surpise. Sleep enable our bodies and minds to consolidate new data and to re-arrange information we have already considered. What is interesting is the emerging work on relational memory. The ability to coordinate lateral, ho