Conditional discrimination learning: A critique and amplification

Carter and Werner recently reviewed the literature on conditional discrimination learning by pigeons, which consists of studies of matching-to-sample and oddity-from-sample. They also discussed three models of such learning: the “multiple-rule” model (learning of stimulus-specific relations), the “configuration” model, and the “single-rule” model (concept learning). Although their treatment of the multiple-rule model, which seems most applicable to the pigeon data, is generally excellent, their discussion of the other two models is incomplete and sometimes inaccurate. Potential problems of terminology are discussed in the present paper, as are additional lines of research that deserve consideration by those interested in further work in this area. The issue of response versus stimulus selection (configuration versus compound-cue learning) is discussed in connection with the configuration model. Particular attention is given to Carter and Werner's criticism of the application, in studies with other species, of the learning set procedure in testing for single-rule learning. Some of the important related issues are: the bias for improvement on new problems in a series, the adequacy of a multiple-rule model to explain learning set formation, and evidence in favor of the single-rule model, at least in primates. Consideration of these additional contributions to the study of conditional discrimination learning emphasizes the usefulness of this task in the comparative study of cognitive processes.     

A developmental study of learning disabilities and memory

Seven-, ten-, and thirteen-year-old learning-disabled (LD) and non-learning-disabled (NORM) children were presented specially structured lists of 38 words each and tested for free recall. Each list contained only four semantically related words. Two of the four related words were presented contiguously (serial positions 9 and 10) and the other two words were spaced (serial positions 20 and 30). All children recalled disproportionately more adjacent words (item 9 or 10) than any other words. Spaced words (items 20 and 30) were less likely to be recalled by the younger children than by the older children and by the LDs than by the NORMS. These findings provided support for the distinction between automatic and purposive semantic processing. NORMs' recall was governed by purposive semantic processing to a greater extent than was LDs' recall. However, no group or age differences were observed in automatic semantic processing.     

Animal learning and memory and their relation to human learning and memory

For some three decades now, the experimental study of learning and memory has been conducted as two entirely separate endeavors, one using humans as subjects and the other using animals. The separation is placed in historical context, and consideration is given to recent movements by those in the animal camp toward adopting some of the theorizing as well as some of the list memory procedures from those in the human camp. It is argued that exploring list memory in animals should do much to further our understanding of both animal cognition and its relation to human cognition. The trend toward more complex theorizing and more liberal use of hypothetical constructs, on the other hand, is regarded with concern. It is argued that hypothetical constructs have contributed little to an enduring understanding of human learning and memory, and that they are unlikely to be any more helpful with animals.     

A model of memory in concept learning

A concept learning model was developed and tested in two conjunctive attribute identification tasks. The model includes assumptions about the focus of attention, decision making, and memory for stimulus information and prior decisions. Predictions are made about how S changes his hypothesis following an error. Procedures in both tasks allowed inference of the subject's current hypothesis. The hypothesis selections and error statistics were in the majority of cases accurately predicted by the model. Deviations from predictions on hypothesis sampling occurred for naive Ss but not for trained Ss who were required to state a hypothesis on each trial.     

A reexamination of the role of imagery in learning and memory

Five experiments were conducted to examine whether the superior recall of concrete over abstract words might be better accounted for in terms of relative differences in the processing of relational and distinctive information rather than redundant verbal and imaginal memory codes. Concrete and abstract word pairs were presented in the standard paired-associated learning task or under conditions intended to affect the nature and extent of relational processing between pair members. Concreteness effects were attenuated or eliminated when relational processing was prevented at encoding (Experiments 3, 4, and 5) or when the use of encoded relations within pairs was prevented at recall (Experiments 1, 2, and 3). The results indicated the viability of an account of concreteness effects in paired-associate learning based on the joint functions of distinctive and relational information. They also remove theoretical constraints imposed on imagery theories by the incorrect assumption of a uniform presence of concreteness effects in memory for word lists.     

Anxiety, learning, and memory: A reconceptualization

A new theoretical framework for work on anxiety and memory is proposed. Anxious subjects engage in task-irrelevant processing which preempts processing resources and some of the available capacity of working memory. They typically attempt to compensate for the adverse effects of this task-irrelevent processing on task performance by increased effort. It follows from these theoretical assumptions that anxiety will have differential effects on performance efficiency (i.e., the quality of performance) and on processing effectiveness (i.e., performance efficiency/effort). Anxiety will always reduce processing effectiveness, but will not impair performance efficiency if there is sufficient effort expenditure. Consequently, reliance on measures of performance efficiency will often obscure the detrimental effects of anxiety on processing effectiveness.     

The neurobiology of learning and memory

The study of memory is a great challenge, perhaps the greatest in biological sciences. Memory involves changes in a tiny fraction of an extremely large pool of elements, a conclusion that makes the task of finding those changes using current technologies formidable. What can be done about this roadblock to neurological investigations of learning? One response that has become particularly productive in recent years is to study learning or learning-like phenomena in relatively simple "model" systems. The idea is to extract basic principles from these models in which molecular and anatomical details can be studied and then to use these in analyzing learning in higher regions of the brain. In this article we discuss current progress and emerging concepts derived from the simple system approach using animal models.     

A role for the perceptual representation memory system in category learning

There is growing evidence that working memory, episodic/semantic memory, and procedural memory all play important roles in at least some types of category learning. Little is known, however, about the role of the perceptual representation memory system (PRS). Two experiments are reported that provide evidence that under certain conditions, the PRS, by itself, is sufficient to mediate category learning. Both experiments compared performance in (A, not A) and (A, B) prototype distortion category-learning tasks, in which category exemplars are created by randomly distorting one category prototype in the (A, not A) conditions or two prototypes in the (A, B) conditions. Results showed that (A, not A) performance was more sensitive to prototype similarity and less affected by the removal of feedback than (A, B) performance. These results support the hypothesis that (A, not A) performance was mediated by the PRS, but that (A, B) performance recruited other memory systems.     

Category learning and multiple memory systems

Categorization is a vitally important skill that people use every day. Early theories of category learning assumed a single learning system, but recent evidence suggests that human category learning may depend on many of the major memory systems that have been hypothesized by memory researchers. As different memory systems flourish under different conditions, an understanding of how categorization uses available memory systems will improve our understanding of a basic human skill, lead to better insights into the cognitive changes that result from a variety of neurological disorders, and suggest improvements in training procedures for complex categorization tasks.     

Extinction in human learning and memory

In two experiments, participants were given extinction training in a human causal learning task. In both experiments, three critical experimental cues were paired with different outcomes in a first phase of training and were then extinguished in a second phase. Three control cues were given the same treatment in the first phase of training, but were not then presented in the second phase. Participants' ability to correctly identify the outcome with which each cue had been paired in the first phase was lower for extinguished than for control cues. Causal attributions to the extinguished cues were also lower than those to the control cues, a difference that correlated with outcome memory. These data are consistent with the idea that extinction in causal judgement is due, at least in part, to a failure to remember the cue-outcome relationship encoded in the first phase of training.     

Extinction in human learning and memory

In two experiments, participants were given extinction training in a human causal learning task. In both experiments, three critical experimental cues were paired with different outcomes in a first phase of training and were then extinguished in a second phase. Three control cues were given the same treatment in the first phase of training, but were not then presented in the second phase. Participants' ability to correctly identify the outcome with which each cue had been paired in the first phase was lower for extinguished than for control cues. Causal attributions to the extinguished cues were also lower than those to the control cues, a difference that correlated with outcome memory. These data are consistent with the idea that extinction in causal judgement is due, at least in part, to a failure to remember the cue–outcome relationship encoded in the first phase of training.     

Aberrant learning and memory in addiction

Over the past several years, drug addiction has increasingly been accepted to be a disease of the brain as opposed to simply being due to a lack of willpower or personality flaw. Exposure to addictive substances has been shown to create enduring changes in brain structure and function that are thought to underlie the transition to addiction. Specific genetic and environmental vulnerability factors also influence the impact of drugs of abuse on the brain and can enhance the likelihood of becoming an addict. Long-lasting alterations in brain function have been found in neural circuits that are known to be responsible for normal appetitive learning and memory processes and it has been hypothesized that drugs of abuse enhance positive learning and memory about the drug while inhibiting learning about the negative consequences of drug use. Therefore, the addict's behavior becomes increasingly directed towards obtaining and using drugs of abuse, while at the same time developing a poorer ability to stop using, even when the drug is less rewarding or interferes with functioning in other facets of life. In this review we will discuss the clinical evidence that addicted individuals have altered learning and memory and describe the possible neural substrates of this dysfunction. In addition, we will explore the pre-clinical evidence that drugs of abuse cause a progressive disorder of learning and memory, review the molecular and neurobiological changes that may underlie this disorder, determine the genetic and environmental factors that may increase vulnerability to addiction, and suggest potential strategies for treating addiction through manipulations of learning and memory.     

Contextual inference in learning and memory

Context is widely regarded as a major determinant of learning and memory across numerous domains, including classical and instrumental conditioning, episodic memory, economic decision-making, and motor learning. However, studies across these domains remain disconnected due to the lack of a unifying framework formalizing the concept of context and its role in learning. Here, we develop a unified vernacular allowing direct comparisons between different domains of contextual learning. This leads to a Bayesian model positing that context is unobserved and needs to be inferred. Contextual inference then controls the creation, expression, and updating of memories. This theoretical approach reveals two distinct components that underlie adaptation, proper and apparent learning, respectively referring to the creation and updating of memories versus time-varying adjustments in their expression. We review a number of extensions of the basic Bayesian model that allow it to account for increasingly complex forms of contextual learning.     

Assessing learning and memory in pigs

In recent years, there has been a surge of interest in (mini) pigs (Sus scrofa) as species for cognitive research. A major reason for this is their physiological and anatomical similarity with humans. For example, pigs possess a well-developed, large brain. Assessment of the learning and memory functions of pigs is not only relevant to human research but also to animal welfare, given the nature of current farming practices and the demands they make on animal health and behavior. In this article, we review studies of pig cognition, focusing on the underlying processes and mechanisms, with a view to identifying. Our goal is to aid the selection of appropriate cognitive tasks for research into pig cognition. To this end, we formulated several basic criteria for pig cognition tests and then applied these criteria and knowledge about pig-specific sensorimotor abilities and behavior to evaluate the merits, drawbacks, and limitations of the different types of tests used to date. While behavioral studies using (mini) pigs have shown that this species can perform learning and memory tasks, and much has been learned about pig cognition, results have not been replicated or proven replicable because of the lack of validated, translational behavioral paradigms that are specially suited to tap specific aspects of pig cognition. We identified several promising types of tasks for use in studies of pig cognition, such as versatile spatial free-choice type tasks that allow the simultaneous measurement of several behavioral domains. The use of appropriate tasks will facilitate the collection of reliable and valid data on pig cognition.     

The im-possibility of secular critique: The future of religion's memory

The legacy of secular critique, with its Greek, Christian, Kantian, modernist traces, constitutes an aporetic law (or contradiction). That law is this: a critical legacy, if it is critical, can affirm and sustain itself only by trying to separate it from itself (from the very crisis that it is). The legacy or history of ‘religion’ is always a history of such critique. Such a legacy always anticipates critiquing itself, its memory (of whatever kind – racist, sexist, colonialist, nationalist). Such a legacy of critique is always a legacy of crisis. However, the crisis of such a legacy cannot be resolved, because critique, as kairos/krisis (critical/decisive moment), can admit of no resolution. Yet the (secular) history of religion, if it is ever historical, can only be a history of such aporetic critique. Such an aporetic critique will be the heritage of religion's im-possible ¹ ?1. I write the word impossible/impossibility with and without a hyphen. When I hyphenate im-possible, I do so to remain true to Derrida's use of it. The im-possible is irreducible to either possibility or impossibility. Sometimes Derrida also writes the word without hyphenating it, but he still implies such irreducibility. future. It is an im-possible future because it will always be a promise, a promise to separate it from itself, a promise that will remain always deferred, always to come. Today, the promise of this secular critique is (in) democracy with its sovereign ‘decisive’ politics. We can no longer simply critique the (future) legacy of religion, understood this way. To do so is to fulfil that legacy's own messianic wish. This is the aporetic limit of secular critique. To think at the limits of the legacy of the critique of religion is to think the very question of the (secular) history of ‘religion’ and its others, that is, ‘religions’.