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Biomedical subjects

D C Geary

Publications and source records attributed to D C Geary.

14 recordsLinked to original sources
PubMed1992

Counting knowledge and skill in cognitive addition: a comparison of normal and mathematically disabled children.

The relationship between counting knowledge and computational skills (i.e., skill at counting to solve addition problems) was assessed for groups of first-grade normal and mathematically disabled (MD) children. Twenty-four normal and 13 MD children were administered a series of counting tasks and solved 40 computer-administered addition problems. For the addition task, problem-solving strategies were recorded on a trial-by-trial basis. Performance on the counting tasks suggested that the MD children were developmentally delayed in the understanding of essential and unessential features of counting and were relatively unskilled in the detection of certain forms of counting error. On the addition task, the MD children committed many more computational errors and tended to use developmentally immature counting procedures. The immature counting knowledge of the MD children, combined with their relatively poor skills at detecting counting errors, appeared to underlie their poor computational skills on the addition task. Suggestions for future research are presented.

Child↗
PubMed1991

Cognitive addition: strategy choice and speed-of-processing differences in young and elderly adults.

Sixty young and 60 elderly adults completed a pencil-and-paper addition test and solved 40 computer-presented simple addition problems. Strategies and problem solution times were recorded on a trial-by-trial basis and were classified in accordance with the distributions of associations model of strategy choices. The elderly group showed a performance advantage on the ability measure and for the developmental maturity of the mix of problem-solving strategies, but the young group showed an advantage for overall solution times. A componential analysis of the overall solution times for memory retrieval trials, however, showed no reliable age difference for rate of retrieving addition facts from long-term memory but did suggest that the elderly adults might have been slower than the younger adults for rate of encoding digits and verbally producing an answer. Overall results are interpreted within the context of the strategy choice model.

Adolescent↗
PubMed1991

Reliability and validity of retrospective self-reports of the age of pubertal onset using twin, sibling, and college student data.

This study presents a methodology, derived from behavioral genetic research, designed to evaluate the validity of retrospective self-report inventories. The application of this technique to college student, twin, and sibling data demonstrated the reliability and validity of a retrospective self-report questionnaire on the timing of pubertal onset. Support was provided by four main findings: (1) substantial test-retest reliability coefficients for individual items (r ranged from .73 to .97) were obtained for a sample of college students; (2) nearly all of the monozygotic twin (MZ) intraclass correlations exceeded those for dizygotic twins (DZ); (3) the magnitude of the test-retest and intraclass correlations for recall of the timing of pubertal onset followed theoretical expectations for a trait demonstrating significant genetic influence (i.e., r for the same individual tested twice greater than r for MZs greater than r for DZs greater than r for siblings); (4) the expected secular trend of a cross-generational decrease in the age of sexual maturation was demonstrated for retrospective self-reports of family members representing three different generations. Moreover, the size of the mean differences across generations mirrored those reported for nonretrospective assessments of the actual age of pubertal onset. Finally, the value of retrospective self-report surveys in psychological research is discussed, and the relative merits of these instruments as indices of individual differences in pubertal development, as opposed to indices of the actual age of sexual maturation, are emphasized.

Adolescent↗
PubMed1990

A componential analysis of an early learning deficit in mathematics.

This study was designed to assess strategy choice and information-processing differences in normal and mathematically disabled first and second grade children. Twenty-three normal and 29 learning disabled (LD) children solved 40 computer-presented simple addition problems. Strategies, and their associated solution times, used in problem solving were recorded on a trial-by-trial basis and each was classified in accordance with the distributions of associations model of strategy choices. Based on performance in a remedial education course, as indexed by achievement test scores, the LD sample was reclassified into a LD-improved group and an LD-no-change group. No substantive differences comparing the normal and LD-improved groups occurred in the distribution of strategy choices, strategy characteristics (e.g., error rates), or rate of information processing. The performance characteristics of the LD-no-change group, as compared to the two remaining groups, included frequent counting and memory retrieval errors, frequent use of an immature computational strategy, poor strategy choices, and a variable rate of information processing. These performance characteristics were discussed in terms of the strategy choice model and in terms of potential long-term memory and working memory capacity deficits. In addition, implications for remedial education in mathematics were discussed.

Achievement↗
PubMed1990

Metamemory and academic achievement: testing the validity of a group-administered metamemory battery.

This study was designed to assess the validity of a recently introduced group-administered battery of metamemory tasks for children and to concurrently assess the relationship between performance on these tasks and academic achievement for second- and fourth-grade normal and learning-disabled (LD) children. Consistent with theoretical predictions and with results from individually administered metamemory tasks, significant age-related performance differences were found for four of the battery's five subtests. However, three of these four performance differences appeared to be due to a floor effect--that is, the second graders performed at chance levels for all but one of the subtests. Nevertheless, modest zero-order correlations between academic achievement measures and scores on metamemory subtests, which did show interpretable age-related performance differences, were found, as were significant group (normal versus LD) differences for fourth graders. In all, these results provided some support for the validity and the utility of the group-administered metamemory battery, although the performance of young children must be interpreted with caution.

Achievement↗
PubMed1989

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.

Adolescent↗
PubMed1988

Rorschach predictors of therapeutic outcome for inpatient treatment of children: a proactive study.

The present study tested the hypothesis that Rorschach measures of psychological instability and perceptual sensitivity (i.e., es, es-EA, Lambda, Blends, Zf, & Zsum) would be sensitive to therapeutic change after inpatient treatment of children. Twelve male children were administered the Rorschach Ink Blot test in accordance with Exner's (1986) procedures and comprehensive system, pretreatment and posttreatment. The 12 children received inpatient treatment an average of 12 months, and all children showed improved functioning after treatment. Pre- to posttreatment Rorschach performance changes provided a partial confirmation of the hypothesis. Specifically, significant changes in es and Lambda were found posttreatment. As such, these Rorschach variables appear to be sensitive to therapeutic change in children.

Adolescent↗
PubMed1987

Individual differences in cognitive arithmetic.

Unities in the processes involved in solving arithmetic problems of varying operations have been suggested by studies that have used both factor-analytic and information-processing methods. We designed the present study to investigate the convergence of mental processes assessed by paper-and-pencil measures defining the Numerical Facility factor and component processes for cognitive arithmetic identified by using chronometric techniques. A sample of 100 undergraduate students responded to 320 arithmetic problems in a true-false reaction-time (RT) verification paradigm and were administered a battery of ability measures spanning Numerical Facility, Perceptual Speed, and Spatial Relations factors. The 320 cognitive arithmetic problems comprised 80 problems of each of four types: simple addition, complex addition, simple multiplication, and complex multiplication. The information-processing results indicated that regression models that included a structural variable consistent with memory network retrieval of arithmetic facts were the best predictors of RT to each of the four types of arithmetic problems. The results also verified the effects of other elementary processes that are involved in the mental solving of arithmetic problems, including encoding of single digits and carrying to the next column for complex problems. The relation between process components and ability measures was examined by means of structural equation modeling. The final structural model revealed a strong direct relation between a factor subsuming efficiency of retrieval of arithmetic facts and of executing the carry operation and the traditional Numerical Facility factor. Furthermore, a moderate direct relation between a factor subsuming speed of encoding digits and decision and response times and the traditional Perceptual Speed factor was also found. No relation between structural variables representing cognitive arithmetic component processes and ability measures spanning the Spatial Relations factor was found. Results of the structural modeling support the conclusion that information retrieval from a network of arithmetic facts and execution of the carry operation are elementary component processes involved uniquely in the mental solving of arithmetic problems. Furthermore, individual differences in the speed of executing these two elementary component processes appear to underlie individual differences on ability measures that traditionally span the Numerical Facility factor.(ABSTRACT TRUNCATED AT 400 WORDS)

Cognition↗
PubMed1987

Structure of adaptive behavior: I. Replication across fourteen samples of nonprofoundly mentally retarded people.

A two-step procedure was used to investigate the dimensional structure of adaptive behavior of mildly, moderately, and severely mentally retarded people. The first step consisted of item factor analyses of the 66-item Client Development Evaluation Report for two derivation samples, each containing 3,024 subjects; results revealed a high degree of cross-sample similarity. Using the preceding results, we conducted parcel factor analyses for 14 samples of retarded people (average sample size, 676). These analyses resulted in a quite stable six-factor structure of adaptive behavior: Motor Development, Independent-Living Skills, Cognitive Competence, Social Competence, Social (or Extrapunitive) Maladaption, and Personal (or Intrapunitive) Maladaption. The implications for research and theory of the highly replicable six-factor structure of adaptive behavior were discussed.

Activities of Daily Living↗
PubMed1985

Performance on the Luria-Nebraska Neuropsychological Test Battery-Children's Revision: a comparison of children with and without significant WISC-R VIQ-PIQ discrepancies.

Fifty-six children, aged 8 to 13, were divided into three groups based on the degree and direction of their WISC-R VIQ-PIQ discrepancies. Group 1 was composed of 13 males and 6 females whose PIQ exceeded their VIQ by at least 12 points (V less than P); Group 2 was made up of 12 males and 6 females with VIQs that exceeded their PIQs by 12 or more points (P less than V); Group 3 was comprised of 9 males and 10 females whose V-P differences failed to exceed 8 points in either direction (P = V). The performance of these children on the 11 subscales of the Luria-Nebraska Neuropsychological Battery-Children's Revision was compared. Univariate F-tests revealed significant differences among the groups on the Receptive Speech, p less than .01, and Expressive Language subscales, p less than .001. Further analyses that utilized two-tailed t-tests found the V less than P group to perform significantly less well than the P = V group on the Receptive Speech and Expressive Language scales. The V less than P group was also significantly worse than the P less than V group on the Expressive Language scale. These results suggest a possible differential sensitivity of the children's Luria-Nebraska to verbal and nonverbal cognitive deficits.

Brain Damage, Chronic↗
PubMed1985

Experimental analysis of adherence counseling: implications for hypertension management.

A time series "reversal" design demonstrated that behavioral counseling increased medication adherence from about 60 to 100% for a black, hypertensive patient. However, inadequate pharmacological treatment yielded no clinically important blood pressure decrease. The combination of improved compliance and minimal blood pressure reduction led the patient's physician to explore higher doses and alternate medications to achieve blood pressure control. The physician's aggressive medical treatment was initiated only after the patient's compliance had been improved. Thus, this study suggests that paraprofessional counseling can increase compliance and illustrates the need for both behavioral and physiological data in clinical management to avoid blaming patients for poorly controlled blood pressure.

Adult↗