Overconfidence effects in category learning: A comparison of connectionist and exemplar memory models.

Exemplar and connectionist models were compared on their ability to predict overconfidence effects in category learning data. In the standard task, participants learned to classify hypothetical patients with particular symptom patterns into disease categories and reported confidence judgments in the form of probabilities. The connectionist model asserts that classifications and confidence are based on the strength of learned associations between symptoms and diseases. The exemplar retrieval model (ERM) proposes that people learn by storing examples and that their judgments are often based on the first example they happen to retrieve. Experiments 1 and 2 established that overconfidence increases when the classification step of the process is bypassed. Experiments 2 and 3 showed that a direct instruction to retrieve many exemplars reduces overconfidence. Only the ERM predicted the major qualitative phenomena exhibited in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonology, reading acquisition, and dyslexia: Insights from connectionist models.

The development of reading skill and bases of developmental dyslexia were explored using connectionist models. Four issues were examined: the acquisition of phonological knowledge prior to reading, how this knowledge facilitates learning to read, phonological and nonphonological bases of dyslexia, and effects of literacy on phonological representation. Compared with simple feedforward networks, representing phonological knowledge in an attractor network yielded improved learning and generalization. Phonological and surface forms of developmental dyslexia, which are usually attributed to impairments in distinct lexical and nonlexical processing "routes," were derived from different types of damage to the network. The results provide a computationally explicit account of many aspects of reading acquisition using connectionist principles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-biased interpretation of memory successes and failures in adulthood

This study extends previous research, which has demonstrated that age stereotypes bias the interpretation of everyday memory failures, by examining the responses of 81 young and 84 old participants to questions about the meaning and causes of memory successes and failures. The scenarios used described memory situations in which age differences would be small or nonexistent and included situtional factors that could account for the memory outcome, providing a more stringent test of the age-bias hypothesis. Under such testing conditions, memory successes in old targets are seen to be less typical than for young targets. Moreover, memory failures are seen to be more strongly caused by lack of ability and viewed as more worrisome. Finally, memory outcomes, in general, are perceived to be less controllable for old targets.     

Mathematical and connectionist models of human memory: a comparison

Recent convolution-based models of human memory (e.g. Lewandowsky & Murdock, 1989), have accounted for a wide range of data. However such models require the relevant mathematical operations to be provided to the network. Connectionist models, in contrast, have generally addressed different data, and not all architectures are appropriate for modelling single-trial learning. Furthermore, they tend to exhibit catastrophic interference in multiple list learning. In this paper we compare the ability of convolution-based models and DARNET (Developmental Associative Recall NETwork), to account for human memory data. DARNET is a connectionist approach to human memory in which the system gradually learns to associate vectors, in one trial, into a memory trace vector. Either of the vectors can than be retrieved. It is shown that the new associative mechanism can be used to account for a wide range of relevant experimental data as successfully as can convolution-based models with the same higher-level architectures. Limitations of the models are also addressed.     

Age of acquisition effects in adult lexical processing reflect loss of plasticity in maturing systems: Insights from connectionist networks.

Early learned words are recognized and produced faster than later learned words. The authors showed that such age of acquisition effects are a natural property of connectionist models trained by back propagation when patterns are introduced at different points into training and learning of early and late patterns is cumulative and interleaved. Analysis of hidden unit activations indicated that the age of acquisition effect reflects a gradual reduction in network plasticity and a consequent failure to differentiate late items as effectively as early ones. Further simulations examined the effects of vocabulary size, learning rate, sparseness of coding, use of a modified learning algorithm loss of early items, acquisition of very late items, and lesioning the network. The relationship between age of acquisition and word frequency was explored, including analyses of how the relative influence of these factors is modulated by introducing weight decay. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differentiating the roles of the hippocampus complex and the neocortex in long-term memory storage: Evidence from the study of semantic dementia and Alzheimer's disease.

Several computational models suggest that the hippocampal complex plays a key role in the establishment of new memories, but over time the storage of such memories becomes independent of this region. In support of such models, the authors demonstrate that patients with semantic dementia, who have relative sparing of the hippocampal complex, show a pattern of preserved recent memories and impaired distant memories. In a group study that used the Autobiographical Memory Interview, amnesic patients with Alzheimer's disease showed the more typical temporally graded loss (poor recall of recent memories), whereas patients with semantic dementia showed the reverse pattern. In a single-case study, using the Galton-Crovitz test, a patient with semantic dementia was significantly better at producing autobiographical memories from the most recent 5 years. By contrast, controls provided similarly detailed memories across all time periods back to childhood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory learning and memory impairments following lesions to the hippocampus and perirhinal-entorhinal cortex.

The role of the hippocampus and perirhinal-entorhinal cortex was examined in an olfactory discrimination paradigm. Small neurotoxic lesions of the hippocampus (21% tissue damage) yielded relatively unimpaired olfactory retention across brief (30 s), intermediate (approximately 5 min), and 24-hr delays, whereas impairments were noted at 5-day retention intervals. Larger hippocampal lesions (63% tissue damage) spared memory at intermediate delays, with no impact at 8-day retention intervals. Aspiration lesions directed at the perirhinal-entorhinal cortex produced a variable performance pattern, with impairments noted at intermediate, 24-hr, and 5-day delays. Results suggest the hippocampus is not specifically involved in retaining olfactory information, with additional consideration given to the relationship between lesion size and memory impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and connectionist models of parsing: A reply to MacDonald and Christiansen (2002).

The authors take issue with 3 claims made by M. C. MacDonald and M. H. Christiansen (2002): (a) tha connectionist models of syntactic processing do not have components that function in the sarne way as limitations on working memory (WM) in production system models of psychological processes; (b) that individual differences in WM are related to the efficiency of syntactic processing because both are affected by reading experience; and (c) that individual differences in the nature of phonologica representations affect the efficiency of syntactic processing. The authors argue that the concept of WM cannot be eliminated from models of language processing and that the literature supports the view that syntactic processing involves a specialized WM system. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Learning from mistakes: Inducing analogous solution failures to a source problem produces later successes in analogical transfer.

In 4 experiments the use of analogical problem solving to facilitate the solution to a problem that usually results in persistent solution failures without hints was investigated. The results of Exps 1–3 indicate that spontaneous transfer was facilitated by a manipulation of the surface form of the source problem that tends to induce initial solution failures analogous to those produced to the target problem. Surface similarity of content words and diagrams had no effect on transfer in Exps 1–3. In Exp 4, facilitation of spontaneous transfer was not obtained when source solution failures were prevented. The importance of failed solutions in problem representation and the relationship between problem representation and surface similarity are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deficits in cross-race face learning: Insights from eye movements and pupillometry.

The own-race bias (ORB) is a well-known finding wherein people are better able to recognize and discriminate own-race faces, relative to cross-race faces. In 2 experiments, participants viewed Asian and Caucasian faces, in preparation for recognition memory tests, while their eye movements and pupil diameters were continuously monitored. In Experiment 1 (with Caucasian participants), systematic differences emerged in both measures as a function of depicted race: While encoding cross-race faces, participants made fewer (and longer) fixations, they preferentially attended to different sets of features, and their pupils were more dilated, all relative to own-race faces. Also, in both measures, a pattern emerged wherein some participants reduced their apparent encoding effort to cross-race faces over trials. In Experiment 2 (with Asian participants), the authors observed the same patterns, although the ORB favored the opposite set of faces. Taken together, the results suggest that the ORB appears during initial perceptual encoding. Relative to own-race face encoding, cross-race encoding requires greater effort, which may reduce vigilance in some participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Connectionist models of recognition memory: Constraints imposed by learning and forgetting functions.

Multilayer connectionist models of memory based on the encoder model using the backpropagation learning rule are evaluated. The models are applied to standard recognition memory procedures in which items are studied sequentially and then tested for retention. Sequential learning in these models leads to 2 major problems. First, well-learned information is forgotten rapidly as new information is learned. Second, discrimination between studied items and new items either decreases or is nonmonotonic as a function of learning. To address these problems, manipulations of the network within the multilayer model and several variants of the multilayer model were examined, including a model with prelearned memory and a context model, but none solved the problems. The problems discussed provide limitations on connectionist models applied to human memory and in tasks where information to be learned is not all available during learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of similarity and experience on discrimination learning: A nonassociative connectionist model of perceptual learning.

This article describes a novel connectionist model of perceptual learning (PL) that provides a mechanism for nonassociative differentiation (J. J. Gibson & E. J. Gibson, 1955). The model begins with the assumption that 2 processes—1 that decreases associability and 1 that increases discriminability—operate during preexposure (S. Channell & G. Hall, 1981). In contrast to other models (e.g., I. P. L. McLaren, H. Kaye, & N. J. Mackintosh, 1989), in the current model the mechanisms for these processes are compatible with a configural model of associative learning. A set of simulations demonstrates that the present model can account for critical PL phenomena such as exposure learning and effects of similarity on discrimination. It is also shown that the model can explain the paradoxical result that preexposure to stimuli can either facilitate or impair subsequent discrimination learning. Predictions made by the model are discussed in relation to extant theories of PL. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The seven sins of memory: Insights from psychology and cognitive neuroscience.

Examines how and why memory can get us into trouble. It is suggested that memory's misdeeds can be classified into 7 basic "sins": transience, absentmindedness, blocking, misattribution, suggestibility, bias, and persistence. The first 3 sins involve different types of forgetting, the next 3 refer to different types of distortions, and the final sin concerns intrusive recollections that are difficult to forget. Evidence is reviewed concerning each of the 7 sins from relevant sectors of psychology (cognitive, social, and clinical) and from cognitive neuroscience studies that include patients with focal brain damage or make use of recently developed neuroimaging techniques. Although the 7 sins may appear to reflect flaws in system design, it is argued instead that they are by-products of otherwise adaptive features of memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An experimental case study of the successes and failures of job enrichment in a government agency.

An experimental job enrichment program was introduced in 3 clerical work units ( N = 1,000 workers) of a federal agency. Matched control groups were selected for each experimental unit. The program was introduced after careful diagnosis of the work situation and thorough training of the personnel involved. Within the limits imposed by the field situation, before-after measures of both behavior and attitudes suggested that changes in behavior (e.g., productivity, absences) occurred in favor of the experimental groups. Job enrichment apparently had no effect on attitudes, however. On the basis of interviews and observations, the productivity changes were attributed mainly to more efficient use of manpower, elimination of unnecessary operations, and feedback and competition, while the absence changes were attributed mainly to initial changes in morale based on the expectation of extrinsic rewards. It is concluded that attitudes did not improve because the expectations and desire for such rewards had not been met. The problem and limitations of job enrichment are discussed. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Base-rate effects in category learning: A comparison of parallel network and memory storage-retrieval models.

Exemplar-memory and adaptive network models were compared in application to category learning data, with special attention to base rate effects on learning and transfer performance. Subjects classified symptom charts of hypothetical patients into disease categories, with informative feedback on learning trials and with the feedback either given or withheld on test trials that followed each fourth of the learning series. The network model proved notably accurate and uniformly superior to the exemplar model in accounting for the detailed course of learning; both the parallel, interactive aspect of the network model and its particular learning algorithm contribute to this superiority. During learning, subjects' performance reflected both category base rates and feature (symptom) probabilities in a nearly optimal manner, a result predicted by both models, though more accurately by the network model. However, under some test conditions, the data showed substantial base-rate neglect, in agreement with M. A. Gluck and G. H. Bower (see record 1989-00340-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Daily stressors and memory failures in a naturalistic setting: Findings from the va normative aging study.

Laboratory studies of stress and memory have generally found that people with more stress tend to have poorer cognitive performance. The present investigation examined the relationship between stressors and memory failures in a naturalistic setting via a daily diary study of 333 older adults in the VA Normative Aging Study. Multilevel models indicated that on days when people experienced stressors, particularly interpersonal stressors, they were more likely to report memory failures. These stressors were also associated with an increase in memory failures from one day to the next. The findings may be important for preventions to mitigate age-related cognitive decline. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using spiritual interventions in psychotherapy: Practices, successes, failures, and ethical concerns of Mormon psychotherapists.

Two hundred and fifteen (out of 300) randomly selected Mormon psychotherapists were surveyed and asked to indicate how frequently they use various spiritual interventions in psychotherapy and to describe successful and unsuccessful spiritual intervention case examples. The therapists indicated that they use a wide variety of spiritual interventions, including praying silently for clients, teaching spiritual concepts, encouraging forgiveness, and using the religious community as a support. Many spiritual interventions were perceived by the therapists as potentially therapeutic. Process guidelines for using spiritual interventions were offered by the therapists, and ethical concerns (e.g., dual relationships, imposing values) were raised. Implications for psychotherapy practice and training are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acetylcholine modulation of neural systems involved in learning and memory

Extensive evidence supports the view that cholinergic mechanisms modulate learning and memory formation. This paper reviews evidence for cholinergic regulation of multiple memory systems, noting that manipulations of cholinergic functions in many neural systems can enhance or impair memory for tasks generally associated with those neural systems. While parallel memory systems can be identified by combining lesions with carefully crafted tasks, most-if not all-tasks require the combinatorial participation of multiple neural systems. This paper offers the hypothesis that the magnitude of acetylcholine (ACh) release in different neural systems may regulate the relative contributions of these systems to learning. Recent studies of ACh release, obtained with in vivo microdialysis samples during training, together with direct injections of cholinergic drugs into different neural systems, provide evidence that release of ACh is important in engaging these systems during learning, and that the extent to which the systems are engaged is associated with individual differences in learning and memory.     

All updateable objects in working memory are updated whenever any of them are modified: Evidence from the memory updating paradigm.

In a series of experiments, participants were required to keep track of 1 or 2 working memory (WM) objects, having to update their values in 80% of the trials. Updating cost, defined as the difference between update and non-update trials, was larger when 2 objects were involved compared with when there was only 1 object was involved. This finding was interpreted as evidence that the updating process encompasses both objects in WM, even though only 1 of them is actually updated. This feature of WM updating is limited to objects defined as "updateable," throughout the trial sequence. The results are explained by the need to reprogram the phonological loop when updating or the need for desynchronization followed by resynchronization of WM contents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)