MENTAL ARITHMETIC IN AFRICA AND AMERICA: STRATEGIES,PRINCIPLES, AND EXPLANATIONS*

Mental arithmetic abilities were studied among unschooled African adults and American college students. A set of problems tested the use of the four basic arithmetic operations. Performance was analyzed for: strategies, implicit arithmetic principles, and explicit explanations of the principles. Both groups showed accurate mental arithmetic strategies related to the base ten structure of their native counting systems. The American students' mental strategies additionally made use of algorithms based on written place values. Several principles were implicit in the calculation strategies of both groups, and both used these principles to short-cut calculations. Though the African subjects did not, the American subjects did describe these abstract principles in explicit common language or algebraic expressions. Relationships between schooling and cognition are discussed.     

Cortical substrates of taste aversion learning: dorsal prepiriform (insular) lesions disrupt taste aversion learning

The functional relation between restricted damage to ventral primary somatosensory neocortex and the ability of rats to acquire conditioned taste aversion (CTA( was examined by a combination of behavioral and neurohistological techniques. Lesions confined exclusively to the established gustatory neocortex (GN) did not disrupt CTA acquisition, nor did lesions confined to suprarhinal cortical areas ventral to the GN. Lesions that encroached on dorsal prepiriform and insular cortices produced CTA acquisition deficits and damaged a large proportion of efferent projections to the prefrontal and precentral neocortex. In a second experiment, lesions of dorsal prepiriform and insular cortices did not modify taste preference-aversion threshold to any of the four taste modalities. It is concluded tha ventral somatosensory neocortical fields, including the established GN, do not mediate CTA acquisition and that rhinal cortices ventral and posterior to the GN are preferentially involved in associative learning for tastes and illness.     

On comprehending idioms: Do children get the picture?

This study examines children's comprehension of idioms. First, third, and fifth grade children (6, 8, and 10 years old) and college adults were read short stories containing contextual information and a key terminal sentence. The contextual information biased either an idiomatic, a literal, or am ambiguous (neutral) interpretation of the terminal sentence. The terminal sentence contained either an idiom (“fix his wagon”) or a changed form (“repair his wagon”) of the idiom. These manipulations were used to determine the role of contextual information and the conventional forms of idioms in idiom comprehension. After each story, the subjects were asked to explain the terminal sentence and to answer a “yes-no” question about the action described in the story. The results showed that idiomatic explanations and interpretations occurred more frequently for the idiom than the changed forms, and that there were strong developmental increases in making idiomatic interpretations of both forms. The results are discussed in terms of two current models of idiom comprehension.     

Age and sex differences on the hand test

Investigated age and sex differences on the Hand Test across the life span, while statistically partialing-out the effects of educational level and verbal ability. Subjects were 150 individuals (75 males, 75 females) ranging in age from 20 to 86 years, assigned to one of three age groups on the basis of their chronological age. Participants were administered the Hand Test and the WAIS vocabulary subtest; in addition, years of formal education completed for each subject was obtained. Results indicated that even after statistically adjusting for the effects of education and verbal ability, a number of significant Age. Sex, Age and Sex, as well as Age x Sex interactions were obtained on the Hand Test. It was suggested that, as previous criticisms of projective research with the aged are met, a residue of important personality trends persists.     

Changes in a multiple-response repertoire during response-contingent punishment and response restriction: Sequential relationships

A multiple-response baseline of four activities was established using gerbils as subjects. When one of the baseline responses was punished (Experiment 1) or restricted (Experiments 2 and 3), only the most probable of the alternative baseline responses increased. The response most likely to follow the punished or restricted responses during baseline sessions was also suppressed during subsequent punishment or response-restriction treatment.     

Stimulus discriminability in free-operant and discrete-trial detection procedures.

Six pigeons were trained to discriminate different light intensities in four experimental procedures. Experiment 1 compared stimulus discriminability in a yes-no signal-detection task with discriminability measures obtained from two free-operant procedures. Discriminability estimates were significantly lower in the detection procedure. Experiment 2 showed this lowered discriminability to be a function of the delay between stimulus presentation and the availability of the choice-response keys in the standard detection task. In addition, reinforcement sensitivity was lowest when correct choice responses were intermittently, rather than continuously, reinforced.     

Identifying emergent leaders in psychotherapy groups

This paper is the second in the series on group development and emergent leadership. It describes the design of a sociometric instrument which will be used for the identification of the four emerging leaders from the perspective of the group participants themselves. These four leaders, Task, Emotional, Scapegoat and Defiant, perform ongoing maintenance functions in the group and take up the critical function of spokesmen in the group's dialectical processing of phase-specific, group level issues. The goal here is to design an instrument which would allow both clinician and researcher to identify these critical persons early in a group's life.Ariadne P. Back is in private practice in Chicago, Illinois.     

Engaging families in therapy: A pilot study

Engagement is reviewed as a central component of marriage and family therapy and presented as a viable means of assessing the nature and outcome of therapy. A tentative model containing six differentiated engagement categories is described and documented with clinical data and case examples. Conclusions drawn indicate engagement has merit as a construct for evaluating marriage and family therapy and as a means of generating process hypotheses in research. Recommendations to validate, refine and revise the model are posited and further research relative to engagement is advocated.James P. Trotzer, Ph.D. is Professor of Counselor Education at the University of Visconsin-River Falls, River Falls, Wisconsin 54022, marriage and family therapist in private practice