Automatic and effortful processing in Attention Deficit/Hyperactivity Disorder

Twenty-five boys with Attention Deficit/Hyperactivity Disorder and 23 age-matched controls were compared on verbal memory tasks differentiating automatic versus effortful information processing. Automatic processing tasks included the recognition of new or old words in a list and the recognition of frequency of occurrence of words in a list. Effortful tasks included free recall of lists of both related and unrelated words. Hyperactive boys did not differ from controls in automatic processing capabilities but demonstrated significantly poorer effortful processing. Intercorrelations of the variables revealed high correlations between scores on effortful measures and also raise questions about the purity of automaticity in some tasks employed. Stepwise discriminant analysis demonstrated that free recall of related words (an effortful task) best discriminated between groups. Effort-related processing in hyperactive and normal children is discussed in relation to variables of motivation, affect, arousal, and other higher-order cognitive processes.     

Classical conditioning of the eyeblink response in the delay paradigm in adults aged 18-83 years

To determine if age differences in classical conditioning of the eyelid response begin to appear in middle age in humans as they do in animals, adult subjects aged 18-83 years were trained in the delay conditioning paradigm. Large age effects occurred. Statistically significant differences first appeared in the decade of the 40s. Within-age-group variability was large. To reduce variability, subjects were classified by the magnitude of their unconditioned response (UR). Regardless of age, subjects with low amplitude URs conditioned poorly. In the normal UR amplitude group, the correlation between age and total percentage conditioned responses (CRs) was -.58. Eyeblink rate and voluntary responding did not account for age differences in conditioning, and it was unlikely that hearing acuity or corneal sensitivity caused the differences. Parallels between human and animal eyelid conditioning are considered, and it is suggested that age changes in the cerebellum may affect conditioning in aging mammals, including humans.     

Word-to-word variation in ERP component latencies: spoken words

Data were collected shedding light on the brain electrical activity underlying word recognition. Subjects listened to a list of 48 spoken words in six random orders under two instructional sets: first to "think about the meanings of the words," and second, to learn the list. The scalp EEG associated with hearing and identifying the words was recorded at F3, F4, Cz, P3, P4, Pz, and Oz. Standard within-subjects time-locked averaging across words showed a late negative-positive complex with N2-P3 topography, the negative component peaking around 480 msec, the positive component peaking around 830 msec. Averaging within words across subjects uncovered considerable latency variability in both components. Within-word N2 and P3 component latencies covaried with word durations and with the "recognition points" predicted for the words by the "cohort theory" of word recognition. N2 latencies corresponded closely to the "N400" effect elicited with semantically incongruous sentence-final spoken words. Implications for ERP investigations of language processing are discussed.     

THE NEUROBIOLOGY OF LEARNING AND MEMORY: William James in Retrospect

William James did much to set the stage for psychobiology. Beyond insisting that brain structures and processes must be the basis of explanations of mental phenomena, he expressed ideas about brain localization and plasticity in neural networks that foreshadowed many aspects of current neurobiology of learning and even connectionist theory.     

Development of gender discrimination: Role of stereotypic and counterstereotypic gender cues

Toddlers (41 girls and 35 boys) between 18 and 37 months old were given four gender discrimination tasks, each consisting of 6 pairs of color drawings. Three tasks depicted pairs of preschool girls and boys holding either sex-typical toys (stereotypic cues), sex-atypical toys (counterstereotypic cues), or no toys. The fourth task paired pictures of female-typed and male-typed toys. For each pair, subjects were asked to point to either the girl (girls' toy) or boy (boys' toy). Gender discrimination increased with age. Young children performed at chance level on all tasks. Older children made fewer correct choices on the Toy Alone task than on the tasks depicting children. Performance generally was unaffected by stereotyping or counterstereotyping of gender cues. Sex differences were minimal.Portions of this paper were presented at the meeting of the Society for Research in Child Development, Baltimore, MD, April 1987.     

Reconstructing the dates of personal events: Gender differences in accuracy

One commonly held stereotype is that females are more concerned with, and attentive to, dates than are males. One possible implication of this idea is that females have a more welldeveloped temporal reference schema than males, which should allow females to reconstruct the dates on which past events have occurred with more accuracy than males. This accuracy hypothesis was assessed by re-analysing the data from four studies collected in previous work on the accuracy of event dating. Analyses of two of the studies yielded evidence for more accurate female dating; analysis of a third study produced a substantial, but non-significant, trend in the predicted direction; and analysis of the fourth study yielded a small, but nonsignificant, reversal. A meta-analysis combining the results of these four studies indicated that the dating accuracy of females was superior to the dating accuracy of males. Additional analyses indicated that these differences were probably not due to differences in self-disclosure patterns.