Active selection of items to be remembered: The role of timing

A series of experiments was carried out in which Ss were required to extract critical stimuli from a stream of nine spoken inputs, presented at various rates, and report on these after the presentation of each list. The critical items were normally digits at positions 2, 4, 6, and 8 in the input sequence. Subjects were required to employ either an “active” extraction strategy, aimed at achieving temporary storage only of items to be remembered, or a “passive” strategy, involving storage of all inputs with subsequent extraction of critical items. The initial experiment showed that the active strategy markedly improved performance efficiency as the presentation rate decreased; passive performance remained relatively stable. Experiments 2 and 3 indicated that the level of active performance was higher when critical items were categorically different from unwanted items. There were indications that this effect was independent of the effect of changes in the presentation rate.The final experiments in the series showed that when Ss were denied the opportunity of predicting the time of arrival of critical items active performance hardly benefitted from a reduction in rate.A “controlled activation” process is proposed as a basis for S's ability to modulate his state of alertness, so as to maximize receptivity for critical stimuli arriving at well-defined points in time.     

A multivariate investigation of the reinforcer structure of occupations

Earlier research based on 81 Occupational Reinforcer Patterns (ORPs) suggested a nine-category classification of occupations. The present research, based on 148 ORPs, investigated the ability of that classificatory system to assimilate new information. Cluster analysis of the 148 ORPs yielded an eight-category classification of occupations in which five of the original occupational clusters appeared virtually unchanged; the other four original clusters were combined into two occupational clusters. One new cluster was identified. Principal factors analysis was employed to study the factor structure of the occupational reinforcers and to highlight the essential nature of the classificatory system. Five reinforcer factors were identified.     

Individual differences in speed of phonemic analysis, visual analysis, and reading.

College student subjects (Ss) classified phrases as making sense or not according to sound in one condition, according to visual appearance in another, and in abasic task in which either strategy would yield right answers. Ss who were relatively fast in the visual condition were faster at the basic task than Ss who were relatively fast in the sound condition. Other results suggested that the former Ss used a visual strategy in the basic task while the latter used a phonemic strategy.     

Sensitivity and responsivity measures for discrimination learning

The present report considers alternative measures of sensitivity and response bias for the discrimination learning paradigm. The classical signal detection measures, d′ and β, were compared with their nonparametric equivalents, A′ and B″, with theoretical measures derived from threshold theory and with empirical measures derived from the ROC graph. Differential rabbit eyelid conditioning data from three experiments were analyzed with these measures, and the results of these analyses were used along with other information to determine which measures of sensitivity and response bias are most useful for the analysis of discrimination learning data.     

Effects of sucrose concentrations on single alternation runway responding in rats

Rats received runway training under alternating reward and nonreward in which rewarded (R) trials provided 32 or 4% sucrose concentration from a drinking tube and nonrewarded (N) trials provided a dry tube or, for half of the rats in the 32% condition, plain water. Both 32 and 4% concentrations yielded faster running on R trials than on N trials; but this effect was reliable only for the 32% condition. Compared to 4% sucrose, 32% sucrose yielded reliably slower running on N trials and unreliably faster running on R trials.