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 Gluck and Bower (1988b).     

Perceptual and motor factors in the imitation of simple temporal patterns

Summary This study investigated the relative importance of perceptual and motor factors in the imitation of simple temporal patterns. Previous research in which subjects tap out interval sequences using one finger has suggested that perceptual factors play an important role in response timing. Studies of bimanual tapping, in contrast, stress the importance of motor interactions between the two hands. In this experiment we compared the ability of subjects to tap out two-interval sequences using one finger, two fingers on one hand, and two fingers on opposite hands. The results showed almost identical performance under the three response conditions. It is suggested that the perceptual relations between intervals in a pattern were the main determinant of performance in this experiment.     

Age deficits in recall under optimal study conditions

Young and older adults studied lists of words under both standard and optimal study conditions for subsequent free recall. Under optimal conditions, the participants studied each word for as long as they wished, were allowed to take notes, and were encouraged to actively use whatever strategies they thought would maximize recall. Both age groups recalled more words under optimal study conditions than under standard conditions, but the improvement was greater for the young adults. This increase in the age-related recall deficit was not due to differences in study time. The results suggest that standard laboratory memory tasks do not overestimate the memory deficits of older adults because of a failure to provide either optimal learning conditions or sufficient study time.     

Central-place foraging by Rattus norvegicus on a radial maze

We studied central-place foraging in rats (Rattus norvegicus) by placing food items that varied in size and weight at the ends of a 4-arm radial maze. In Experiments 1-3, rats increasingly tended to carry food to the center of the maze as the size of those items increased. Very large food items often were hoarded in the center. Rats consumed food faster on the arms than in the center, and rats traveled faster when carrying food than when not. Blocking arm entrances increased travel time between the center and the arms and decreased food carrying at every item weight except the largest. In Experiments 4-6, important conditions that influence the degree of food-carrying behavior were discovered; these were the intersection of maze arms, the presence of a conspecific, and the use of open vs. closed maze arms.     

Perioral somatosensory determinants of nursing behavior in Norway rats (Rattus norvegicus)

Prior to assuming the upright crouching posture over their pups during nursing bouts, lactating rats typically engage in several oral behaviors, including nuzzling, licking and rearranging pups. By acutely depriving dams of various aspects of perioral stimulation from pups (with anesthesia of the mystacial pads or of the tongue, with mouth suturing, or with muzzling), we found the following: (1) Distal stimulation from pups maintains proximity-seeking behavior, but is insufficient to stimulate nursing behavior. (2) Lack of tongue feedback decreases pup licking and hastens the onset of crouching. (3) Snout, but not tongue, contact with pups is required for hovering over them. (4) The position of the dam while hovering over her litter enables the pups to gain access to her ventrum, thereby provoking her upright, crouching posture. (5) Older pups are capable of bypassing the dam's perioral attentions and stimulating crouching directly by burrowing under the dam's ventrum.     

Cross-sex comparisons: A word of caution

A cross-sex difference on one variable is often hypothesized to be related to a gender difference on a second variable. However, caution should be exercised in making such comparative hypotheses. We gathered the expected and actual examination grades for 168 female and 163 male college students. As in prior research, males had higher expectancies than females (p<.05). But analysis of the intrasex regression equations indicated that the relationship of expectancies to performance was different for women than it was for men. Thus, a cross-sex difference in expectancies did not correspond to a parallel difference in grades. This finding highlights the potential hazards of making certain cross-sex comparisons, and we argue for more caution in their application.     

Setting and response generalization in rational-emotive therapy: A case study

A single case study (n=1) conducted during therapy investigated the relationship between disputing irrational beliefs in vivo and setting and response generalization. Irrational beliefs associated with the subject's anger and depression were disputed at different intervals over a ten week period utilizing a multiple baseline design across four classes in a school setting (setting 1). Depression and anger were rated several times each week. The subject's level of anxiety was also rated in setting 1 but the irrational beliefs associated with it were not disputed. Anger, depression, and anxiety were rated without disputation in a separate work setting (setting 2). Affect ratings significantly decreased across both settings throughout the ten week period. Results indicated that 1) disputing irrational beliefs associated with anger and depression in setting 1 led to reductions in anxiety in this setting (response generalization), 2) anger and depression reductions in setting 2 paralleled setting 1 reductions (setting generalization), and 3) anxiety reductionsWilliam J. Ruth, PhD, Staff Psychologist and practicum supervisor, Institute for Rational-Emotive Therapy, NY City; School Psychologist, Board of Cooperative Educational Services, Southern Westchester.Raymond DiGiuseppe, PhD, ABPP, Director of Training and Research, Institute for Rational-Emotive Therapy, NY City; Graduate Professor, St. John's University, NY City; co-author,Practitioner's Guide to Rational-Emotive Therapy and RET with Alcoholics and Substance Abusers.     

Errors in the quantification of uncertainty: A product of heuristics or minimal probability knowledge base?

The use of intuitive heuristics (e. g. representativeness and availability) has been put forward as an explanation for peoples' assignment of probabilities (Tversky and Kahneman, 1971). This phenomenon is seen as robust since experts as defined by education (professional psychologisis), despite advanced training in statistics and methodology, rely on the same heuristics as novices (lay people). Both experts and novices, as defined by education, were studied in a series of experiments and further classified as experts and novices according to their probability knowledge base, prior to receiving (or not) a brief (15-minute) training session. Immediately following training, subjects completed a probability test which consisted of ten Tversky and Kahneman (e. g. 1974) problems. The training significantly increased the number of problems correctly solved on the probability test and eliminated the expert/novice education classification. The results of a follow-up test 5 weeks after the experiment indicated that the training group maintained its superior performance. It is proposed that failure to use proper methods of probability assignment may not be due to intrinsic human inference biases or heuristics, but is a result of a minimal probability knowledge base.     

Children’s competitive behavior: A challenging alternative

The effect of challenge on the cooperative and competitive behavior of 120 urban American children was assessed using two experimental game apparatuses, one of which provided a challenging cooperative response. Significantly more cooperation was observed when the subjects were presented with a challenging cooperative response. In addition, a reliable age effect was found indicating that the older subject group (10–12 years old) was more cooperative than the younger two age groups (5–7 and 8–10 years old). Finally, a significant game condition x order interaction was discovered suggesting that under some conditions the order in which the games were played affected the degree of subject cooperation. Results are related to a theory of competence motivation. It is argued that cooperation among American children may be increased if the task involves the presence of challenge. A portion of this research was presented at the biennial meetings of the Society for Research in Child Development, Detroit, Michigan, 1983.     

A further empirical evaluation of neurolinguistic primary representational systems (PRS)

Neurolinguistic programmers claim that individuals have preferred (primary) representational systems. These may be auditory, visual or kinesthetic and determine how a person views/deals with the world. Systems can be identified by observation of eye movements. In workshops programmers demonstrated strong associations between eye movements following questioning and types of questions and eye movement categories (assumed to identify systems) and other assessments of systems. Studies have evaluated these ‘workshop’ associations and found little support for their general occurrence. In these studies, it is possible that eye movements following questioning were influenced by artifacts which influence predicted association between these and other variables. An attempt was made to exclude these artifacts in this study. Except for subjects who had attended neurolinguistic workshops, results supported those obtained elsewhere. Possibly, associations in workshops occur as a result of expectational-contextual variables.