One of the fundamental questions raised by Ruchkin, Grafman, Cameron, and Berndt's (Ruchkin et al.'s) interpretation of no distinct specialized neural networks for short-term storage buffers and long-term memory systems, is that of the link between perception and memory processes. In this framework, we take the opportunity in this commentary to discuss a specific working memory task involving percept formation, temporary retention, auditory imagery, and the attention-based maintenance of information, that is, the verbal transformation effect.

The goal of our target article was to review a number of emerging facts about the effects of limbic damage on memory in humans and animals, and about divisions within recognition memory in humans. We then argued that this information can be synthesized to produce a new view of the substrates of episodic memory. The key pathway in this system is from the hippocampus to the anterior thalamic nuclei. There seems to be a general agreement that the importance of this (...) pathway has previously been underestimated and that it warrants further study. At the same time, a number of key questions remain. These concern the relationship of this system to another temporal-lobe/diencephalic system that contributes to recognition, and the relationship of these systems to prefrontal cortex activity. (shrink)

This paper argues that the biochemistry of memory consolidation provides valuable model systems for exploring the multiple realization of psychological states.

Dienes & Perner (D&P) argue that nondeclarative knowledge can take multiple forms. We provide empirical support for this from two related lines of research about the development of mathematical reasoning. We then describe how different forms of procedural and declarative knowledge can be effectively modeled in Anderson's ACT-R theory, contrasting this computational approach with D&P's logical approach. The computational approach suggests that the commonly observed developmental progression from more implicit to more explicit knowledge can be viewed as a consequence of (...) accumulating and strengthening mental representations. (shrink)

A functional theory of memory has already been developed as part of a general functional theory of cognition. The traditional conception of memory as “reproductive” touches on only a minor function. The primary function of memory is in constructing values for goal-directedness of everyday thought and action. This functional approach to memory rests on a solid empirical foundation.

In this book, experienced researchers in the field address the question: Will the model survive these challenges?

Based on brain state-dependent behavioral changes, consolidation of sensorimotor memories has been posited to evolve in two different functional stages. Only the second of these stages requires sleep and leads to performance benefits. Recent results, however, suggest that sleep is not always crucial for the expression of delayed behavioral gains but might be critical for enhancing automaticity in the absence of attention, another expression of memory consolidation.

The concept of unconscious knowledge is fundamental for an understanding of human thought processes and mentation in general; however, the psychological community at large is not familiar with it. This paper offers a survey of the main psychological research currently being carried out into cognitive processes, and examines pathways that can be integrated into a discipline of unconscious knowledge. It shows that the field has already a defined history and discusses some of the features that all kinds of unconscious knowledge (...) seem to share at a deeper level. With the aim of promoting further research, we discuss the main challenges which the postulation of unconscious cognition faces within the psychological community. (shrink)

The limited capacity of immediate memory “rides” on the even more limited capacity of consciousness, which reflects the dynamic activity of the thalamocortical core of the brain. Recent views of the conscious narrow-capacity component of the brain are explored with reference to global workspace theory (Baars 1988; 1993; 1998). The radical limits of immediate memory must be explained in terms of biocognitive brain architecture.

?In everday language, the word ?attention? implies control of access to consciousness, and we adopt this usage here. Attention itself can be either voluntary or automatic. This can be readily modeled in the theory. Further, a contrastive analysis of spontaneously self?attributed vs. self?alien experiences suggests that ?self? can be interpreted as the more enduring, higher levels of the dominant context hierarchy, which create continuity over the changing flow of events. Since context is by definition unconscious in GW theory, self in (...) this sense is thought to be inherently unconscious as well. This proposal is consistent with a great deal of objective evidence. However, aspects of self may become known through ?conscious self-monitoring,? a process that ??is useful for self-evaluation and self?control. The results of conscious self-monitoring are combined with self?evaluation criteria, presumably of social origin, to produce a stable ?self?concept?, which functions as a supervisory system within the larger self organization. (shrink)

Conscious perception, like the sight of a coffee cup, seems to involve the brain identifying a stimulus. But conscious input activates more brain regions than are needed to identify coffee cups and faces. It spreads beyond sensory cortex to frontoparietal association areas, which do not serve stimulus identification as such. What is the role of those regions? Parietal cortex support the ‘first person perspective’ on the visual world, unconsciously framing the visual object stream. Some prefrontal areas select and interpret conscious (...) events for executive control. Such functions can be viewed as properties of the subject, rather than the object, of experience – the ‘observing self’ that appears to be needed to maintain the conscious state. (shrink)

Recent studies have shown that schizophrenia may be a disease affecting the states of consciousness. The present study is aimed at investigating metamemory, i.e., the knowledge about one's own memory capabilities, in patients with schizophrenia. The accuracy of the Confidence level (CL) in the correctness of the answers provided during a recall phase, and the predictability of the Feeling of Knowing (FOK) when recall fails were measured using a task consisting of general information questions and assessing semantic memory. Nineteen outpatients (...) were paired with 19 control subjects with respect to age, sex, and education. Results showed that patients with schizophrenia exhibited an impaired semantic memory. CL ratings as well as CL and FOK accuracy were not significantly different in the schizophrenic and the control groups. However, FOK ratings were significantly reduced for the patient group, and discordant FOK judgments were also observed more frequently. Such results suggest that FOK judgments are impaired in patients with schizophrenia, which confirms that schizophrenia is an illness characterized by an impaired conscious awareness of one's own knowledge. (shrink)

The term 'episodic memory' refers to our memory for unique, personal experiences, that we can date at some point in our past - our first day at school, the day we got married. It has again become a topic of great importance and interest to psychologists, neuroscientists, and philosophers. How are such memories stored in the brain, why do certain memories disappear (especially those from early in childhood), what causes false memories (memories of events we erroneously believe have really taken (...) place)? Since Endel Tulving's classic book 'Episodic memory' (OUP, 1983) very few books have been published on this topic. In recent years however, many of the assumptions made about episodic memory have had to be reconsidered as a result of new techniques, which have allowed us a far deeper understanding of episodic memory. In 'Episodic memory: new directions in research' three of the worlds leading researchers in the topic of memory have brought together a stellar team of contributors from the fields of cognitive psychology, neuropsychology, and neuroscience, to present an account of what we now know about about this fundamentally important topic. The list of contributors includes, amongst others, Daniel Schacter, Richard Morris, Fareneh Vargha-Khadem, and Endel Tulving. The work presented within this book will have a profound effect on the direction that future research in this topic will take. (shrink)

A review of the patterns of brain activation observed in implicit and explicit memory tasks indicates that during conscious retrieval studied items are first retrieved nonconsciously and are retained in a buffer at the extrastriate cortex. It also indicates that the awareness of the retrieved item is made possible by the activation of a reentrant signaling loop between the extrastriate and left prefrontal cortices.

A distinction between interpretive processing and post-interpretive processing calls for a consideration of interface relations in systems of verbal memory. Syntactic movement of a phrase and the cognitive system of thought/mind interact. Systems of declarative memory and procedural memory interact.

Extreme conditions like savantism, autism or synaesthesia, which have a neurological 2AH, UK basis, challenge the idea that other minds are similar to our own. In this paper we report a single case study of a man in whom all three of these conditions co-occur. We suggest, on the basis of this single case, that when savantism and synaesthesia co- occur, it is worthwhile testing for an undiagnosed Autism Spectrum Condition (ASC). This is because savantism has an established association with (...) ASC, and the combination of ASC with synaesthesia may increase the likelihood of savantism. The implications of these conditions for philosophy of mind are introduced. (shrink)

From its genesis in the 1960s, the focus of inquiry in neuroscience has been on the cellular and molecular processes underlying neural activity. In this pursuit neuroscience has been enormously successful. Like any successful scientific inquiry, initial successes have raised new questions that inspire ongoing research. While there is still much that is not known about the molecular processes in brains, a great deal of very important knowledge has been secured, especially in the last 50 years. It has also attracted (...) the attention of a number of philosophers, some of whom have viewed it as evidence for a ruthlessly reductionistic program that will eventually explain how mental processes are performed in the brain in purely molecular terms. As neuroscience developed, however, there emerged a smaller group of researchers who focused on systems, behavioral, and cognitive neuroscience. These investigators have also made impressive advances in the last 50 years and they have been the focus of an even larger group of philosophers, who have appealed to systems level understanding of the brain as providing the appropriate point of connection to the information processing accounts advanced in psychology. (shrink)

Some theorists who emphasize the complexity of biological and cognitive systems and who advocate the employment of the tools of dynamical systems theory in explaining them construe complexity and reduction as exclusive alternatives. This paper argues that reduction, an approach to explanation that decomposes complex activities and localizes the components within the complex system, is not only compatible with an emphasis on complexity, but provides the foundation for dynamical analysis. Explanation via decomposition and localization is nonetheless extremely challenging, and an (...) analysis of recent cognitive neuroscience research on memory is used to illustrate what is involved. Memory researchers split between advocating memory systems and advocating memory processes, and I argue that it is the latter approach that provides the critical sort of decomposition and localization for explaining memory. The challenges of linking distinguishable functions with brain processes is illustrated by two examples: competing hypotheses about the contribution of the hippocampus and competing attempts to link areas in frontal cortex with memory processing. (shrink)

(1) Substituting (as Solms does) forebrain for brainstem in the search for a dream “controller” is counterproductive, since a distributed system need have no single controller. (2) Evidence against episodic memory consolidation does not show that REM sleep has no role in other types of memory, contra Vertes & Eastman. (3) A generalization of Revonsuo's “threat simulation” model in reverse is more plausible and is empirically testable. [Hobson et al.; Solms; Revonsuo; Vertes & Eastman].

Glenberg's theory is rich and provocative, in our view, but we find fault with the premise that all memory representations are embodied. We cite instances in which that premise mispredicts empirical results or underestimates human capabilities, and we suggest that the motivation for the embodiment idea – to avoid the symbol-grounding problem – should not, ultimately, constrain psychological theorizing.

Throwing new light on established conditions and introducing two new syndromes, this book is a major contribution to the clinical management of memory disorders ...

Elizabeth Ligon Bjork, Robert A. Bjork. where people studied information in a drug state and then were tested in the same state 4 hr later—people recalled the material better than those who also had learned while under the drug but were ...

Much of our work with enriched experience and training in animals supports the Quartz & Sejnowski (Q&S) thesis that environmental information can interact with pre-existing neural structures to produce new synapses and neural structure. However, substantial data as well as an evolutionary perspective indicate that multiple information-capture systems exist: some are constructivist, some are selectionist, and some may be tightly constrained.

Erdelyi's unified theory includes the idea that traumatic memories can be unconsciously repressed so that they are enduringly inaccessible to deliberate recall. I argue here that clinical evidence for repressed memory is illusory, and illustrate this claim by examining previous studies of putative repressed memories and also recent research on nonverbal behaviors among survivors of childhood sexual abuse.

The problem of cortical integration is described and various proposed solutions, including grandmother cells, cell assemblies, feed-forward structures, RAAM and synchronization, are reviewed. One method, involving complex attractors, that has received little attention in the literature, is explained and developed. I call this binding through annexation. A simulation study is then presented which suggests ways in which complex attractors could underlie our capacity to reason. The paper ends with a discussion of the efficiency and biological plausibility of the proposals as (...) integration mechanisms for different regions and functions of the brain. (shrink)

MacNeilage's target article develops a theory for the evolution of human speech articulation along the lines of “slot- filler” structure. His content/frame schema commits him to the tenets of embodiment, muscle sense, and a memory for speech. My commentary ties these aspects together in their historical and current perspective.

The effort to identify the neural substrate of episodic recall, though ambitious, lacks experimental support. By considering the data on c-fos activation by novel and familiar stimuli in recognition studies, we illustrate how inadequate experimental designs permit alternative interpretations. We stress that interpretation of c-fos expression changes should be supported by adequate recognition tests.

Blair proposes that fluid intelligence, working memory, and executive function form a unitary construct: fluid cognition. Recently, our group has utilized a combined correlational–experimental cognitive neuroscience approach, which we argue is beneficial for investigating relationships among these individual differences in terms of neural mechanisms underlying them. Our data do not completely support Blair's strong position. (Published Online April 5 2006).

We agree with Caplan & Waters that there are problems with the single-resource theory of sentence comprehension. However, we challenge their dual-resource alternative on theoretical and empirical grounds and point to a more coherent solution that abandons the notion of working memory resources.

Walker's target article proposes a refinement of the well known two-stage model of memory formation to explain the positive effects of sleep on consolidation. After a first stage in which a labile memory representation is formed, a further stabilisation of the memory trace takes place in the second stage, which is dependent on (REM) sleep. Walker has refined the latter stage into a stage in which a consolidation-based enhancement occurs. It is not completely clear what consolidation-based enhancement implies and how (...) it can be dissociated from a stage for memory-stabilisation. A more serious consideration, however, is whether a second stage in memory consolidation that is solely dependent on sleep, is really necessary. The classical, passive, interference theory is able to explain adequately the findings related to the effects of sleep and memory, and can lead perhaps better to an understanding of the highly variable data in this field. (shrink)

This is a collection of chapters by some of the most influential memory researchers.

The present commentary agrees with many of the points made by Ruchkin et al., but brings up several important differences in assumptions. These assumptions have to do with the nature of the capacity limit in working memory and the possible bases of working-memory activation.

Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. However, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide variety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits (...) will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recoding of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity-limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed. Key Words: attention; enumeration; information chunks; memory capacity; processing capacity; processing channels; serial recall; short-term memory; storage capacity; verbal recall; working memory capacity. (shrink)

We are sympathetic to most of what Glenberg says in his target article, but we consider it common wisdom rather than something radically new. Others have argued persuasively against the idea of abstraction in cognition, for example. On the other hand, Hebbian connectionism cannot get along without the idea of association, at least at the neural level.

Whoever paid the bill at the restaurant last night, will clearly remember doing it. Independently from the type of action, it is a common experience that being the agent provides a special strength to our memories. Even if it is generally agreed that personal memories (episodic memory) rely on separate neural substrates with respect to general knowledge (semantic memory), little is known on the nature of the link between memory and the sense of agency. In the present paper, we review (...) results from two experiments investigating the effects of agency on both explicit and implicit memory traces. Performance of normal subjects is compared to that of schizophrenic patients in order to explore the role of awareness of action on memory. It is proposed that reliable first-person information is necessary to create a stable and coherent motor memory trace. (shrink)

Recent findings suggest that our capacity to imagine the future depends on our capacity to remember the past. However, the extent to which episodic memory is involved in our capacity to think about what could have happened in our past, yet did not occur (i.e., episodic counterfactual thinking), remains largely unexplored. The current experiments investigate the phenomenological characteristics and the influence of outcome valence on the experience of past, future and counterfactual thoughts. Participants were asked to mentally simulate past, future, (...) and counterfactual events with positive or negative outcomes. Features of their subjective experiences during each type of simulation were measured using questionnaires and autobiographical interviews. The results suggest that clarity and vividness were higher for past than future and counterfactual simulations. Additionally, emotional intensity was lower for counterfactual simulations than past and future simulations. Finally, outcome valence influenced participants’ judgment of probability for future and counterfactual simulations. (shrink)

Most research on the relationship between attention and consciousness has been limited to perception. However, perceptions are not the only kinds of mental contents of which we can be conscious. An important set of conscious states that has not received proper treatment within this discussion is that of memories. This paper reviews compelling evidence indicating that attention may be necessary, but probably not sufficient, for conscious recollection. However, it is argued that unlike the case of conscious perception, the kind of (...) attention required during recollection is internal, as opposed to external, attention. As such, the surveyed empirical evidence is interpreted as suggesting that internal attention is necessary, but probably not sufficient, for conscious recollection. The paper begins by justifying the need for clear distinctions among different kinds of attention, and then emphasizes the difference between internal and external attention. Next, evidence from behavioral, neuropsychological, and neuroimaging studies suggesting that internal attention is required for the successful retrieval of memorial contents is reviewed. In turn, it is argued that internal attention during recollection is what makes us conscious of the contents of retrieved memories; further evidence in support of this claim is also provided. Finally, it is suggested that internal attention is probably not sufficient for conscious recollection. Open questions and possible avenues for future research are also mentioned. (shrink)

The present study is part of recent attempts to specify the characteristics of the counterexample retrieval process during causal conditional reasoning. The study tried to pinpoint whether the retrieval of stored counterexamples (alternative causes and disabling conditions) for a causal conditional is completely automatic in nature or whether the search process also demands executive working memory (WM) resources. In Experiment 1, participants were presented with a counterexample generation task and a measure of WM capacity. We found a positive relation between (...) search efficiency, as measured by the number of generated counterexamples in limited time, and WM capacity. Experiment 2 examined the effects of a secondary WM load on the retrieval performance. As predicted, burdening WM with an attention-demanding secondary task decreased the retrieval efficiency. Both low and high spans were affected by the WM load but load effects were less pronounced for the most strongly associated counterexamples. Findings established that in addition to an automatic search component, the counterexample retrieval draws on WM resources. (shrink)

Two experiments examined the contribution of working memory (WM) to the retrieval and inhibition of background knowledge about counterexamples (alternatives and disablers, Cummins, 1995) during conditional reasoning. Experiment 1 presented a conditional reasoning task with everyday, causal conditionals to a group of people with high and low WM spans. High spans rejected the logically invalid AC and DA inferences to a greater extent than low spans, whereas low spans accepted the logically valid MP and MT inferences less frequently than high (...) spans. In Experiment 2, an executive-attention-demanding secondary task was imposed during the reasoning task. Findings corroborate that WM resources are used for retrieval of stored counterexamples and that people with high WM spans will use WM resources to inhibit the counterexample activation when the type of counterexample conflicts with the logical validity of the reasoning problem. (shrink)

(1) Non-projectable properties as opposed to the clamping of projectable properties play a primary role in triggering and guiding human action. (2) Embodiment in language-mediated memories should be qualified: (a) Language imposes a radical discretization on body constraints (second-order embodiment). (b) Metaphors rely on second-order embodiment. (c) Language users sometimes suspend embodiment.

Subjects classified visible 2-digit numbers as larger or smaller than 55. Target numbers were preceded by masked 2-digit primes that were either congruent (same relation to 55) or incongruent. Experiments 1 and 2 showed prime congruency effects for stimuli never included in the set of classified visible targets, indicating subliminal priming based on long-term semantic memory. Experiments 2 and 3 went further to demonstrate paradoxical unconscious priming effects resulting from task context. For example, after repeated practice classifying 73 as larger (...) than 55, the novel masked prime 37 paradoxically facilitated the “larger” response. In these experiments task context could induce subjects to unconsciously process only the leftmost masked prime digit, only the rightmost digit, or both independently. Across 3 experiments, subliminal priming was governed by both task context and long-term semantic memory. (shrink)