The Role of Consciousness in Memory — Brains, Minds & Media
In addition, this paper employs the word “consciousness” or “conscious . coherent episodes separated by quite short periods of no conscious content . Figure 1 displays some of the relationships between the memory systems we'll discuss. Dissertation Abstract: Consciousness, Perception, and Short-Term Memory When we I suggest that if we identify perceptual experience with the process of. Memories are not retrieved from long-term memory always in the same then the relationship between autobiographical memories and other.
In some trials in which the target was absent, a semantically related distractor such as a motorbike helmet was present instead. The surprising result of this experiment, which involved an eye-tracking camera, was that subjects reliably fixated upon either targets or semantically related distractors with their initial eye movements, and were just as likely to do whether the arrays contained 4 or 8 items, and even when assigned a cognitive load task beforehand see Figure 3.
Again, these results arguably point to the existence of some further memory mechanism beyond sensory memory and working memory: However, let us proceed on the assumption that the CSTM hypothesis is at least worth taking seriously, and that there may be some high-capacity semantic buffer in addition to more widely accepted mechanisms such as iconic memory and working memory. What relevance might this have for debates in philosophy and cognitive science? I will now briefly mention three such topics.
Again, I will be oversimplifying somewhat, but my goal will be to outline some areas where the CSTM hypothesis might be of interest. The first such debate concerns the nature of the contents of perception. Do we merely see colours, shapes, and so on, or do we perceive high-level kinds such as tables, cats, and Donald Trump Siegel, ? Taking our cue from the data on CSTM, we might suggest that this question can be reframed in terms of which forms of short-term memory are genuinely perceptual.
If we take there to be good grounds for confining perceptual representation to the kinds of representations in sensory memory, then we might be inclined to take an austere view of the contents of experience. By contrast, if the kind of processing involved in encoding in CSTM is taken to be a form of late-stage perception, then we might have evidence for the presence of high-level perceptual content.
However, more positively, this might provide a way of grounding largely phenomenological debates in the more concrete frameworks of memory research. A second key debate where CSTM may play a role concerns the presence of top-down effects on perception. Such claims have been forcefully challenged by the likes of Firestone and Schollwho have suggested that the relevant effects can often be explained in terms of, for example, postperceptual judgment rather than perception proper.
However, the CSTM hypothesis may again offer a third compromise position. By distinguishing core perceptual processes namely those that rely on sensory buffers such as iconic memory from the kind of later categorical processing performed by CSTM, there may be other positions available in the interpretation of alleged cases of top-down effects on perception. This would allow us to claim that at least some putative cases of top-down effects went beyond mere postperceptual judgments while also respecting the hypothesis that early vision is encapsulated; see Pylyshyn, As noted earlier, Ned Block has argued that information in sensory forms of memory may be conscious even if it is not accessed — or even accessible — to working memory Block, Again, CSTM may offer a compromise position.
As noted earlier, the capacity of CSTM does indeed seem to overflow the sparse resources of working memory. Thus one new position, for example, might claim that information must at least reach the stage of CSTM to be conscious, thus allowing that perceptual experience may indeed overflow working memory while also ruling it out in early sensory areas.
These are all bold suggestions in need of extensive clarification and argument, but it is my hope that I have at least demonstrated to the reader how CSTM may be a hypothesis of interest not merely to psychologists of memory, but also those interested in broader issues of mental architecture and consciousness.
And while I should also stress that CSTM remains a working hypothesis in the psychology of memory, it is one that I think is worth exploring on grounds of both scientific and philosophical interest. Looking back and looking forward.
"Consciousness, Perception, and Short-Term Memory" by Henry F. Shevlin
It has long been widely held that only humans can have conscious self-reflection. But recent research with macaque monkeys provides some of the first evidence that nonhuman primates may also be capable of self-reflective behavior. This required the monkeys to gauge the state of their own knowledge — essentially, how certain they were about the bets the experimenters requested them to make.
But Metcalfe described two macaques, Ebbinghaus and Lashley, who were essentially behaving metacognitively — or self-reflecting.
Still, Metcalfe is quick to caution: This may not be true self-reflection of the human variety. This special metacognitive decision makes direct reference to the self.
From early findings she and her colleagues reported that humans have an acute sense of knowing when they are in control of their physical actions. Metcalfe is taking this idea down to the micro level. She hopes to show that the elusive notion of conscious self-knowledge — a feeling of agency — lies in our ability to recognize a match between imagined and actual physical movement. Hicks pointed to puzzling conclusions from recent research using the remember—know paradigm.
The remaining three steps of the cognitive cycle impact this account of what the IDA model has to say about memory by producing the actions that are shaped using conscious contents from subsequent cycles. In Step 6 of the cycle, the recruiting function of consciousness, the central hypothesis of global workspace theory, is implemented. Relevant behavior codelets respond to the conscious broadcast. These are typically codelets whose variables can be bound assigned a value from information in the conscious broadcast.
If the successful attention codelet s was an expectation codelet announcing an unexpected result from a previous action, the responding codelets may be those some of whose actions can help to rectify the unfulfilled expectation. They also bind variables, and send activation to behaviors.
Here, we assume that there is such a behavior codelet and behavior stream. If not, then non-routine problem solving is called for, using additional mechanisms involving the execution over multiple cycles of a partial planning algorithm Gerevin and Schuber implemented as a behavior stream.
This part of the IDA conceptual model is, as yet, unpublished. Relationships between some of the various memory systems Step 8: This choice may come from the just instantiated behavior stream or from a previously active stream. The pervasive influence of feelings and emotions on the various memory systems and on action selection is another part of the IDA conceptual model Franklin and McCauley Action is taken in Step 9, the final step of the cycle.
This part of the process is IDA taking an action. The acting codelets also include at least one expectation codelet see Step 4 whose task it is to monitor the action taken, and to try and bring its results to consciousness, particularly any failure.
The Learning of Interpretations Though semantic memory, a part of declarative memory DMand perceptual memory PM have quite similar content, their functions and processes are different.
Memory and Consciousness: Consciousness to Unconsciousness and Back Again
In the IDA model, PM is implemented with an activation-passing semantic net called a slipnet Hofstadter and Mitchellwhile DM is implemented using an expanded version of sparse distributed memory Kanerva ; Anwar, Dasgupta and Franklin ; Anwar and Franklin These distinct mechanisms were chosen to reflect the respective different functions of each type of memory.
DM is accessed in Step 3 of the cognitive cycle to retrieve local associations with the current contents of the WM buffers. PM, on the other hand, is the critical element in the process of assigning interpretations to sensory input in Step 1. These quite distinct functions lead us to hypothesize distinct neural mechanisms for DM and PM in humans. Base-level activation curve of slipnet nodes. This and other such figures are included only for the general shape of the curve.
The units are arbitrary. PM is centrally involved in the processes of recognition, categorization, and concept formation. In the IDA model, recognition, categorization and the assignment of other interpretations happens in the slipnet. In Step 1 of the cognitive cycle, perceptual codelets search incoming stimuli, internally or externally generated, for features of interest to their special purpose.
Those finding such features activate appropriate nodes in the slipnet. Activation in the slipnet spreads from node to node along relationship links. Nodes that are highly active at this point provide the interpretations assigned to the incoming stimuli. In Step 2 of the cognitive cycle, these interpretations recognitions, categorizations, and otherstogether with some of the incoming data, are stored into WM buffers.
How is it stored Gilbert, Sigman, and Crist. To answer this question, we need more detailed knowledge of the structure of the slipnet. Each node has a base-level activation analogous to the at-rest firing rate of a neuron.
Additional activation provided by perceptual codelets, or spread from other nodes, is added to this base-level activation. A low base-level activation decays quite rapidly, while a saturated base-level activation decays almost not at all see Figure 5. Links in the slipnet model relationships between nodes, concepts. Each link carries a weight that acts as a multiplier of activation spreading over the link.
Similar to base-level activation of nodes, the weights on link increase along a saturating, sigmoidal curve according to the number of occurrences of its relationship in the contents of consciousness see Figure 4.
Also, the weight of the link decays inversely to its magnitude with a saturated weight decaying almost not at all see Figure 5. PM is updated simultaneously with the broadcast.
The base-level activation of a slipnet node is increased whenever it represents an interpretation that appears in the broadcast contents of consciousness. Similarly, the weight on any slipnet link corresponding to a relationship appearing in the broadcast contents of consciousness is increased. In humans, with consciousness in cognitive cycles occurring roughly five times a second, this incremental learning may not be so slow.
The previous paragraph describes the updating of existing nodes and links. But are such nodes and links originally learned and, if so, how? The general outline of how this is accomplished is as follows. An attention codelet succeeds in bringing to consciousness a new individual, a recent instance of a new category, or some other form of a new concept. The absence of an existing node for this concept triggers a mechanism that produces an appropriate new node within the slipnet.
Each relationship of the new concept with another individual, category or other concept within the current contents of consciousness triggers the generation of a new link between their respective nodes in the slipnet. A new node begins with a tiny base-level activation level; a new link begins with a tiny weight. Thus a new node or link is likely to decay away unless it receives reinforcement from the contents of consciousness during subsequent cognitive cycles. Should one, for example, be introduced to a new person at a party, shake hands, exchange a greeting and move on, the new node for the person just met would have come to consciousness only a dozen or so times, not producing much in the way of base-level activation.
On the other hand, a ten-minute conversation with the new acquaintance might result in some three thousand appearances in subsequent conscious contents, resulting in a much higher base-level activation.
In the first case, a sighting of the new person a few weeks later might result in no recognition at all. In the second case, recognition should occur and bring with it memories of the conversation. One might reasonably ask at this point about the role of perceptual codelets in the learning of interpretations.
Just as Edelman postulates a primary repertoire of neuronal groupswe propose a primary repertoire of perceptual codelets evolved into natural systems and built into artificial systems. As do behavior codelets see the next sectionperceptual codelets have base-level activation that affects the total activation they can pass to appropriate nodes after noting the particular features with which they are concerned.
Each conscious broadcast leads to the updating of these base-level activations just as happens for behavior codelets. Each broadcast also results in appropriate associations between perceptual codelets and newly added nodes in perceptual memory. A node would not correspond to a neuron. Nor do we think it would correspond to a collection of neurons. Perhaps it would be best to think of the slipnet as modeling, in the dynamical system sense, an attractor landscape with nodes corresponding to attractors and links to their boundaries.
The well-known decades of difficulty computer scientists have had with pattern recognition leads us to believe that only a dynamical systems approach is likely to be successful in the real world. This approach has certainly been successful in modeling classification by means of olfaction in rabbits Skarda and Freeman ; Freeman and Skarda ; Freeman and Kozma. Procedural Learning Our account of procedural learning is based on consciousness providing reinforcement to actions.
Global workspace theory has actions performed by special purpose processors. These are implemented in the IDA model by behavior codelets. We take them as neurally corresponding to neuronal groups Edelman Edelman postulates an organism being born with an initial repertoire of neuronal groups. An initial set of primitive actions, implemented by primitive codelets or some such, is a computational necessity for any autonomous agent, natural or artificial, software or robotic Franklin In the IDA model codelets have preconditions that must be satisfied in order that the codelet can act.
They also have post-conditions that are expected after the actions take place. Each codelet also has a numerical activation that roughly measures its relevance and importance to the current situation.
Part of this activation is base-level activation similar to that described for slipnet nodes above. Behavior codelets acquire environmental activation during Step 7 of each cognitive cycle see above in proportion to their preconditions being satisfied. In that same step, a behavior codelet may receive activation if its post-conditions help to satisfy some goal or drive as implemented by an emotion or feeling.
Collections of primitive behavior codelets form behaviors. This corresponds to collections of processors forming goal contexts in global workspace theory. Behaviors also have pre- and post-conditions derived from those of their underlying codelets. The activation of a behavior is always the sum of the activations of its codelets.
- Consciousness and Memory
- Conceptual short-term memory: a new tool for understanding perception, cognition, and consciousness
Thus, behaviors acquire activation for their codelets. They may also receive activation from other behaviors that they must share with their codelets. Collections of behaviors, called behavior streams, with activation passing links between them, correspond to goal context hierarchies in global workspace theory.
They can be thought of as partial plans of actions. Also during Step 7, behavior streams are instantiated into an on going, activation passing, behavior net.
In Step 8 of each cycle, the behavior net chooses exactly one behavior to execute. More details of the operation of this action selection mechanism have been published elsewhere Negatu and Franklin