A componential model for mental addition

A componential model capable of representing simple and complex forms of mental addition was proposed and then tested by using chronometric techniques. A sample of 23 undergraduate students responded to 800 addition problems in a true-false reaction time paradigm. The 800 problems comprised 200 problems of each of four types: two single-digit addends, one single- and one double-digit addend, two double-digit addends, and three single-digit addends. The results revealed that the columnwise product of addends, a structural variable consistent with a memory network retrieval process, was the best predictor of mental addition for each of the four types of problem. Importantly, the componential model allowed estimation of effects of several other structural variables, e.g., carrying to the next column and speed of encoding of digits. High levels of explained variance verified the power of the model to represent the reaction time data, and the stability of estimates across types of problem implied consistent component use by subjects. Implications for research on mental addition are discussed.     

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).     

Parts of visual objects: an experimental test of the minima rule

Three experiments were conducted to test Hoffman and Richards's (1984) hypothesis that, for purposes of visual recognition, the human visual system divides three-dimensional shapes into parts at negative minima of curvature. In the first two experiments, subjects observed a simulated object (surface of revolution) rotating about a vertical axis, followed by a display of four alternative parts. They were asked to select a part that was from the object. Two of the four parts were divided at negative minima of curvature and two at positive maxima. When both a minima part and a maxima part from the object were presented on each trial (experiment 1), most of the correct responses were minima parts (101 versus 55). When only one part from the object--either a minima part or a maxima part--was shown on each trial (experiment 2), accuracy on trials with correct minima parts and correct maxima parts did not differ significantly. However, some subjects indicated that they reversed figure and ground, thereby changing maxima parts into minima parts. In experiment 3, subjects marked apparent part boundaries. 81% of these marks indicated minima parts, 10% of the marks indicated maxima parts, and 9% of the marks were at other positions. These results provide converging evidence, from two different methods, which supports Hoffman and Richard's minima rule.     

Developmental and individual differences in preschoolers' recognition memories: The influences of gender schematization and verbal labeling of information

Eighty-three 37-92-month-old children's gender schematization and recognition memories for gender-typed content were assessed. Verbal labeling of stimuli and age were positively associated with children's memories. Highly gender schematic children displayed better memories for gender-role consistent information and committed more gender transformation errors than less gender schematic children. Interactions between children's gender schematization, age, and labeling condition were observed. Labeling of stimuli facilitated less schematic children's memories for gender-role consistent information. Gender schematization was positively associated with younger children's memories, suggesting younger children's memories are more strongly mediated by gender schematization than older children's. Results support the position that studies of gender schema development require an integrated approach recognizing individual and developmental differences in gender schematic processing.Completion of this project was facilitated by funds received while the author was a National Institute of Mental Health Postdoctoral Fellow at the University of Denver: Grant 5T32 MH 15780-09. This support is gratefully acknowledged. An earlier version of this paper was presented at the Conference on Human Development, Charleston, South Carolina, 1988. The author would like to thank the faculty and staff of the Tiny Tot, Jack & Jill, Little Learners II, Plymouth and Upstate preschools for their assistance and cooperation. The author wishes to recognize James Aber, Rosanne David, Melisa Shack, and Susan Zigelbaum for their exceptional service in conducting the project; and would also like to thank Joan Barth, D. Bruce Carter, Gail S. Goodman, Carol L. Martin, William J. Meyer, Kathy Park, Ralph J. Roberts, Jaipaul L. Roopnarine, Margaret L. Signorella, and the anonymous reviewers for their comments and suggestions on earlier drafts of this article.     

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.     

Does motor encoding enhance relational information?

Summary Three experiments investigated whether learning action phrases by enacting the denoted action enhances organization or not. In the first experiment it was shown that, compared to a standard learning instruction, enacting did not enhance the clustering of episodic and taxonomic lists, but it did enhance memory performance. Furthermore, the enacting effect was strongest with an unrelated list; in all lists, organization and recall correlated only under a verbal instruction and not under an enacting instruction. In the second experiment, subjects were also informed about the categories of the lists and instructed to use them to learn the items. The organization was enhanced in all cases by this procedure, but the recall performance was enhanced only with a standard learning instruction. Under enacting, information about the categories had no influence. In the third experiment this effect was replicated for a taxonomic list and could be generalized for a motor list, in which categories were in accordance with the similarities of the movement pattern. Here too the explicit category information had an effect only under a standard learning instruction, but not with enacting. We interpret these effects as support for the assumption that enacting does not enhance memory performance by better relational information. Relational information is, on the contrary, less important for recall under enacting than under a standard learning instruction.     

Modality specificity of implicit memory for new associations

In previous research we demonstrated that newly acquired associations between unrelated word pairs influence the magnitude of priming effects on word-completion tests. This phenomenon of implicit memory for new associations is observed only following semantic study elaboration. The present experiments reveal that implicit memory for new associations, though elaboration dependent, is also modality specific: Associative effects on a visual word-completion test were consistently reduced by study-test modality shifts. In contrast, explicit memory for new associations, as indexed by cued-recall performance, was uninfluenced by modality shifts. The modality effect on completion performance was eliminated when subjects were given brief visual preexposures to, or were required to construct visual images of, word pairs presented in auditory study conditions. The results pose a theoretical puzzle insofar as they indicate that within the domain of implicit memory, access to the products of elaborative processing depends on modality-specific, sensory-perceptual processing.     

The social phobia and anxiety inventory: Construct validity

The Social Phobia and Anxiety Inventory (SPAI) is a new instrument composed of social phobia and agoraphobia subscales. The latter scale is used to detect social anxiety that may result from agoraphobia. The SPAI's construct validity was assessed through several procedures. First, confirmatory factor analyses were conducted to validate the existence of the two subscales. Second, exploratory factor analyses examined the underlying structure of the social phobia subscale. Third, a Q factor procedure determined if different anxiety diagnostic groups could be differentiated by their SPAI response pattern. The results confirmed the utility of the two SPAI subscales and identified a number of dimensions contained within the social phobia subscale which differed depending upon the specific subject sample. In addition, the complaints of social phobies appeared more homogeneous than those of an agoraphobic comparison group. The results are discussed in terms of construct validity and the sensitivity of the SPAI to various dimensions of social phobia fears.This study was supported in part by NIMH Grants 41852, 30915, 18269, and 16884.