Sample duration and type of stimuli in delayed matching-to-sample in rhesus monkeys

Two experiments were performed to determine the effect of sample duration (0.1, 2, and 4 sec), delay interval (.03, 4, 8, 16, and 32 sec), and type of stimulus (color and shape) on the matching performance of rhesus monkeys. In Experiment 1, the 15 possible delay-duration combinations were randomly presented in blocks of 15 trials. In Experiment 2, each duration was held constant and the five delays randomly presented. Then each delay interval was held constant with the three durations randomly varied. Matching performance increased as sample duration increased (ps < .01 and .005), while length of delay did not significantly affect performance. The type of stimuli paired in the matching test significantly affected performance (ps < .05 and .10) with the shape/shape choices leading to the poorest performance. Stimulus discriminability and amount of training with brief sample durations were implicated as significant determinants of matching performance.     

Children's internal organization of locative categories

4 locative categories were investigated to determine whether their examples were organized according to the prototype/nonprototype distinction. A ranking task was presented to 30 adult subjects to see whether they would judge those instances which had been designated as prototypes by the experimenter to be the best exemplars of each category. An elicited-drawing task was administered to see whether there was a preference for drawing adult-designated prototypical instances. A matching task was presented to determine whether fewer errors would occur in response to adult-designated prototypical instances. The latter 2 tasks were presented to 4-year-olds, 6-year-olds, and adults, with 17 subjects in each group. The results provide strong evidence of prototype/nonprototype organization in 3 of the locative categories and weak evidence in the fourth. Tentative conclusions regarding the development of such organization are drawn.     

Improving the compositions of students with learning disabilities using a strategy involving product and process goal setting.

This study was conducted to determine if a planning and writing strategy would improve the essay writing of students with learning disabilities. Four participants were taught a strategy designed to facilitate the setting of product and process goals, generation and organization of notes, continued planning during writing, and evaluation of goal attainment. Training effects were investigated using a multiple probe design across subjects. Strategy instruction had a positive effect on students' essay writing performance and knowledge of the writing process, and effects were maintained over time.