A study of neuropsychological impairment among school-indentified learning-disabled students

This investigation examined the proportion of school-identified learning-disabled (LD) students who scored in the impaired range on the Halstead Reitan Neuropsychological Battery for Children (HNBC) over a 20-year period. A difference was noted in findings for periods before and after the passage of federal legislation (Public Law 94-142); specifically, the proportion of LD students who scored in the impaired range on neuropsychological tests was significantly higher prior to than after this law. A similar pattern of impaired performance across the different tests was noted before and after the legislation. The implications of these results for theorists and practitioners are discussed.     

Tasks and timing in the perception of linguistic anomaly

Three experiments were conducted to investigate the relative timing of syntactic and pragmatic anomaly detection during sentence processing. Experiment 1 was an eye movement study. Experiment 2 employed a dual-task paradigm with compressed speech input, to put the processing routines under time pressure. Experiment 3 used compressed speech input in an anomaly monitoring task. The outcomes of these experiments suggest that there is little or no delay in pragmatic processing relative to syntactic processing in the comprehension of unambiguous sentences. This narrows the possible explanations for any delays that are observed in the use of pragmatic information for ambiguity resolution.The research reported in this paper was supported by Program Project Grant HD-01994 to Haskins Laboratories from the National Institutes of Child and Human Development, and in part by a grant to Stephen Crain and Donald Shankweiler from the University of Connecticut Research Foundation. We thank Jacques Mehler and Gerry Altmann for helpful information about speech compression algorithms. We are especially grateful to Ignatius Mattingly for his generous expert advice on speech compression and design of the experimental materials, and also for recording all the speech stimuli. Julie Boland, Brian McElree, Janet Nicol, and Martin Pickering provided very helpful advice on an earlier draft.     

Many-Valued Logic and Event-Related Potentials

In previous experiments on event-related potentials (ERPs) during linguistic judgments, the subjects' decisions have been categorical (e.g., true vs false). In this experiment, more realistic variations in truth value and subject certainty were used. Thirty-eight naive undergraduates read a story about a fictional murder. ERPs were recorded as the subjects rated the strength of their beliefs about statements relating to suspects in the crime. Because no subject was sure which of the suspects was guilty of committing the crime, binary (true–false) category judgments were inappropriate. Three components of the ERP waveforms were affected by the experimental manipulations. An early positive component was largest to sentences concerning the suspect considered most likely to have committed the crime. A subsequent broad posterior positivity (LPC) also showed significant sentence-type differences, but it was larger to sentences considered probable—whether they were true or false—than to more ambiguous sentences. A third ERP component (N400) was negative at midline electrode sites and peaked at approximately 420 ms. Subjects' truth-value judgments had no effect on the N400. N400 was, however, affected by the subject's task. It was more negative when subjects made graded judgments about truth value than when they made binary true–false judgments. Overall, naturalistic judgments of sentence validity produced a variety of brain responses that reflected different aspects of linguistic decision making.     

Matching adolescents with foster mothers and fathers: An evaluation of the role of temperament

We tested the notion that better foster care adjustment would be observed when the temperaments of mothers and fathers were matched with those of adolescent foster children. We hypothesized that families in which foster parents and foster children had high (easy) scores on subscales of the Revised Dimensions of Temperament Scale (DOTS-R) would also report higher family functioning and higher foster care adjustment than parents and children from families in which one or both family members had low (difficult) scores on these scales. The hypotheses were supported when the mothers and fathers family assessments were used but rejected when the observations of the case managers and adolescents were tested. Methodological and substantive explanations for the findings are discussed and recommendation for foster care practice and continuing research are provided.     

Stimulus control and delayed reinforcement

Pigeons were tested for generalization along the line-orientation dimension, after being trained on various two-component multiple schedules. The first component contained either a variable-interval 1-min schedule of immediate reinforcement or an extinction schedule and was associated with a plain white key (S1). The second component contained a variable-interval 1-min schedule of delayed reinforcement and was associated with a black line on a white background (S2). The major results showed that (a) decremental gradients were obtained around the stimulus associated with the delayed reinforcement component when S1 was associated with extinction, but that incremental gradients were obtained when S1 was associated with immediate reinforcement, (b) the subjects' pretraining did not affect the generalization gradients if sufficient training on the terminal multiple schedule was provided, and (c) changing the S1 schedule from immediate reinforcement to extinction produced behavioral contrast if reinforcement was delayed for 10 sec during S2, but not if it was delayed for 20 sec.     

Memory for music

Subjects created imaginal interpretations of classical music passages in accordance with themes which were either concrete and comprehensible or abstract and difficult to comprehend. Recognition memory for the musical passages was found to be superior in the former condition. The results support the hypothesis that meaningful interpretation of stimulus material is a major determinant of memory accuracy. The implications of the results for comparisons of music and language are also discussed.     

Classes,collections, and distinctive features: Alternative strategies for solving inclusion problems

This study analyzed the strategies that children ages 5 through 8 years used on two modified versions of Inhelder and Piaget's (The early growth of logic in the child. New York: Norton, 1964) class inclusion task. In two experiments, children were tested on Wilkinson's (Cognitive Psychology, 1976, 8, 64–85) “percept” inclusion task in which distinctive features marked both supraordinate and subclasses. It was hypothesized that children who fail standard Piagetian inclusion tasks succeed on the “percept” task by counting and comparing mutually exclusive features rather than using features as markers for classes and subclasses. The hypothesis was supported by children's performances on “percept” tasks in which solutions based on feature counting conflicted with solutions based on consideration of class inclusion relations. In two other experiments, children answered part-whole and part-part comparison questions in which both terms were described as classes and/or subclasses, or in which one of the two terms was described as a collection (e.g., a bunch of grapes). These experiments contrasted Markman and Seibert's (Cognitive Psychology, 1976, 8, 561–577) “organization” hypothesis that the greater psychological integrity of collections facilitates reasoning on part-whole comparison problems with the hypothesis that the faciltative effect results from the “large number” connotation of collective nouns. Results on collection problems in which parts were described as collections supported the “large number” hypothesis. Results were discussed in terms of their implications for Piaget's theory.     

Unequal Power Relationships Within a Cooperative or Corn petit ive Context

Sixty undergraduates negotiated an exchange of resources in dyads. They had either high or low power relative to the other and were within a competitive or cooperative context. Results support the hypothesis that these contexts affect unequal power persons' interaction and relationship. Compared to those in the cooperative context, high and lower power participants in the competitive context suspected each other, refused to exchange resources, developed negative attitudes toward each other, and associated power with control. In addition, low power participants in the competitive context indicated considerable insecurity about the interaction. These results highlight that previous literature has tended, often implicitly, to consider power and unequal power relationships within a competitive context. The dynamics proposed by this literature that inequality of power undermines negotiations and that power refers to the control of another were found to be much stronger within a competitive context than a cooperative one. Whereas the emphasis of the literature has been on power equalization, findings suggest that placing power differences in a cooperative con text can contribute to effective working relationships.     

Crawling-onset age predicts visual cliff avoidance in infants

Two experiments are reported that tested the effects of crawling-onset age, the amount of crawling experience, and testing age on avoidance of the deep side of a visual cliff apparatus by human infants. In Experiment 1, 49 infants ranging in age from 7 to 13 mo. were tested on the visual cliff after 1 or 2 mo. of crawling experience. Discriminant analysis revealed that crawling-onset age, and not crawling experience, discriminated between those infants who crossed and those infants who avoided the apparent drop-off. Infants who crossed the deep side were infants with an early crawling-onset age. In Experiment 2, 40 infants were tested on a visual cliff apparatus, half at 9 and half at 12 mo. of age. Discriminant analysis again found that crawling-onset age discriminated between infants who crossed the infants who would not cross the deep side, whereas testing age alone did not. These results call into question the idea that experience crawling is critical in inducing visually guided avoidance behavior in infants. It is argued that the crawling-onset age effect occurs because crawling during the tactile phase of infancy interferes with later visual control of locomotion.