A probe trial procedure for the study of children's discrimination learning and transfer

A discrimination reversal problem was presented to 192 children varying in age from 3 to 5 years. At the end of both the initial learning and transfer trials, probe trials were introduced to ascertain the response rule describing children's choices. Results were analyzed in terms of a binary division of the children according to their responses to the probe stimuli; children who responded errorlessly (concept responders) were contrasted with children who made errors on the probes (instance responders). Using this criterion, it was found that many children transferred in a way different from the way they learned the initial problem. There was no difference in the proportion of younger and older children responding conceptually to the original problem, but older children were more likely to transfer conceptually when standard geometric blocks were used as stimuli. Future studies must consider the possiblity that learning and transfer may be accomplished by different processes whose application differs with age, the nature of the stimuli, and the stage of training.     

Self-consciousness, self-awareness, and self-attribution

Self-awareness was either manipulated by a mirror (experimental) or not (control). Subjects were selected for being high or low in private self-consciousness (disposition to attend to one's thoughts, feelings, motives). Private self-consciousness had a stronger effect on self-attributions than did self-awareness. These findings have implications for attribution, self-consciousness, and the relationship between manipulations and dispositions.     

Cardiovascular responses to avoidance conditioning in the dog: Effects of alpha adrenergic blockade

Laboratory dogs were trained to press a response panel to postpone shocks during daily one-hour avoidance conditioning periods. Each dog was also confined in the experimental environment for 5 hours prior to the avoidance periods. Blood pressure and heart rate were monitored continuously during these experiments from chronically indwelling arterial catheters. Extended training resulted in the emergence of a cardiovascular response pattern during the pre-avoidance interval characterized by gradual increases in blood pressure together with decreases in heart rate. Elevations in both blood pressure and heart rate were sustained during the avoidance periods. During sessions in which alpha adrenergic activity was suppressed by phenoxybenzamine, absolute levels of blond pressure were found to be lower than during control (non-drug) sessions, but a progressive rise in blood pressure continued to be observed during pre-avoidance. These results suggest that sustained cardiovascular responses during avoidance periods are associated with activation of the sympathetic nervous system, but that the gradual rise in blood pressure during pre-avoidance is due to other factors.     

Divided attention, order of report and responses to immediately successive signals

Two effects, “divided-attention” and “order of report”, are operationally denned. Their relative contributions to the reduction in efficiency which accompanies the recognition of difficult nonverbal signals, presented simultaneously, is considered. Experiment I evaluated the two effects in the absence of a fixed order of report and emphasis instructions, confounding features of previous studies. The results showed: an overall impairment of performance with simultaneous signals; a contribution of both effects to the decrement, with a suggestion of the primacy of the “order of report” effect; and a significant interaction between the latter effect and modality, such that visual signals showed the greater effect. Experiment II using similar signals tested the assumption that simultaneity of presentation is a necessary condition for obtaining reduced efficiency with multiple signals. The assumption was only partially confirmed, a significant decrement in performance occurring only for the second of two successively presented signals. Similarities between the two sets of results are noted, as well as between these and modality differences obtained with verbal materials. Two possible accounts of the data are proposed, one based on “input”, the other on “storage” models of divided-attention. The hypothesis that subjects report the most clearly perceived signal first is rejected as an independent explanation.     

Correlations of normality and nervousness with cardiovascular functions in pointer dogs

Methylphenidate, 0.5 mg/kg, injected intravenously, was used in 10 normal (A line) and 10 genetically nervous (E line) dogs in a blind-design experiment to aid in prediction, from cardiovascular recordings alone, of behavioral normalityversus nervousness. The prediction was 75 per cent correct, based on heart rate (HR), form of the electrocardiogram (EKG), pattern of sinus arrhythmia, and pattern of HR response to methylphenidate. Nervous dogs were found to have slower baseline HR’s, delayed return of HR to baseline after methylphenidate, greater occurrence of baseline EKG abnormalities and much greater frequency of these after methylphenidate. Degree of nervousness was found to correlate rather highly (1)negatively with baseline HR level, (2)negatively with speed of BP response, and (3)positively with frequency of some of the EKG manifestations. These data, indicative of a relative inertness of physiological functions of nervous pointer dogs compared with normal pointers, are consistent with the behavioral and some of the biochemical findings previously reported.     

The cost of categorization in visual search: Incomplete processing of targets and field items

A partial processing hypothesis is proposed to account for performance under a visual search condition where target and field items belong to the different conceptual categories, letter and digit (between-category search), as compared to a condition in which they belong to the same category (within-category search). This hypothesized mechanism implies that less information is registered and/or retained in between- than in within-category search. This prediction was tested and confirmed in three experiments. The results indicate that both targets and field items are processed less deeply in between- than in within-category search.     

Pattern identification of pure tones and frequency glides by untrained listeners

Six subjects identified the order of four-event sequences. Contiguous pure tones (713, 1,031, 1,209, and 1,514 Hz in permuted orders) were presented by earphones at 40 dB SL, with individual events Itones) from 20, to 40, 60, and 300 msec in duration. Again, silent intervals of 20 or 60 msec were inserted among tones of 20 or 40 msec duration. Finally, the pure tones of 713 and 1,209 Hz were combined, in any four-event sequence, with two glissandi chosen from 466 to 714 Hz, from 714 to 1,208 Hz, and their mirror reversals. The temporal and frequency continuity both of tonal and of glissando-plus-tonal sequences affected the identification of sequential order. Degraded performance in the glissando-plus-tonal condition was attributed partially to a subjective experience of pitch blurring. The inclusion of silent intervals in the sequences of the shorter pure-tone durations improved identification performance to that of contiguous sequences of equal overall duration, i.e., adding silent processing time was as efficacious as increasing by the same amount the duration of the individual frequency event.     

A perspective on the recognition of other-race faces

The purpose of the present study is to provide a perspective on the recognition of other-race faces, i.e., black faces by white subjects. Past research has indicated that individuals have greater difficulty recognizing other-race faces than they do same-race faces. On the basis of previous findings, we chose to investigate the recognition of black faces by white subjects as a function of the quantity and quality of previous experience with blacks, racial attitudes, field dependence/independence, and recognition training. Forty-two white subjects participated in pre-, post-, and delayed recognition tests. Subject data were also collected to explore individual differences in recognition performance. Using multiple regression techniques, it was found that field dependence/independence accounted for the largest proportion of variance in recognition performances; a feature-discrimination training task and past experience with blacks were also found to significantly relate to recognition performance. The applied aspects of these results are discussed.