Reinforcement and punishment in a closed system

Children chose between toys freely and with various restrictive contingencies. Sometimes play with a preferred toy was contingent on play with a nonpreferred toy. Sometimes play with a nonpreferred toy was contingent on play with a preferred toy. Another toy (free toy) was always available during contingency sessions. Because toy playing occupied the entire session the response system was closed. When one response increased in duration others had to decrease. An analysis of closed-system responding revealed that the restrictions of the closed system together with the restrictions imposed by the contingencies forced subjects to alter the proportion of time devoted to the three responses. A geometrical model representing the closed system and an analytical method based on distance are presented to describe the data.     

Memory development in adolescence: Relationships between metamemory,strategy use,and performance

Eighth and tenth grade students were asked to study and recall a list of paired associates. The word pairs were available either throughout an 8 sec per word study period or only at the beginning and were composed of either high frequency or low frequency words. After recall, students were asked to indicate which of several study strategies they had used with each word pair (read pair carefully, rehearsal, visual elaboration, verbal elaboration). In addition, they were asked which of these strategies would have had the best effect on recall. Knowledge of appropriate memory strategies (metamemory) was positively related to strategy use, and strategy use was positively related to recall performance at both ages. Improved performance with materials available throughout study and with high frequency word pairs was explained by increased use of elaborative strategies. Age differences in performance were explained by increased strategy effectiveness. These results are discussed in relation to changing relationships among metamemory, strategy use, and performance with age.     

Encoding variability and organization in free recall

Measures of category clustering and subjective organization are well-established predictors of performance in free recall tasks. The present studies demonstrate that a measure of encoding variability affords equally powerful and independent prediction of free recall performance. They also illustrate an interaction between encoding processes and organizational activity. In Experiments 1 and 2, the independent contributions of organization and encoding variability are demonstrated in categorizable and uncategorizable lists and in subjects whose recall is expected to increase (adults) or decrease (children) as a function of more varied encodings across trials. In Experiment 3, a category labeling procedure is used to demonstrate that the negative relationship between encoding variability and recall can be reversed by inducing adult-like organizational activity in children.     

The effect of pictorial detail and elaboration on children's retention.

In a visual memory task, two degrees of stimulus detail were compared to test Reese's hypothesis that stimulus detail would facilitate retention of paired associates for young children. Stimuli were presented in an elaborated or nonelaborated fashion so that the effect of detail on retention of both types of materials could be investigated. Four and 5 year-old children were included to assess a reported developmental trend that elaboration facilitates retention for older children but fails to do so for younger children. Both age groups performed equally well, and detail had no effect. Elaboration aided retention significantly. A second study, in which difficulty of the task was increased, yielded equivalent results. The constraints on performance by recall and recognition tasks were discussed.     

The development of communication: Attribute variation leads to contrast failure

Groups of 5-year-olds in two experiments described multidimensional triangles for a listener. The attribute differentiating referent triangles from nonreferent triangles in Experiment I was constant across trials for the simple condition group, while any one of three attributes was distinctive on a given trial for the complex condition group. One-adjective messages by subjects in the simple condition were virtually always informative; in the complex group, such messages were predominantly ambiguous. The boundaries of the variation effect were assessed in Experiment II. In addition to the simple-complex variation of the relevant attributes, the values of the irrelevant attributes either varied across trials in the diverse groups or remained constant in the constant groups. One-adjective messages were informative only in the simple-constant group; in the other groups, such messages were predominantly ambiguous. Thus, young children can base their communications on a comparative analysis of stimulus arrays, but performance deteriorates when there is any variation in relevant or irrelevant attributes. These results were discussed in relation to various theories of the development of meaning and communication: the cognitive overload theory, the broad context theory, and the perceptual saliency theory.