The use of schemata in the acquisition and transfer of knowledge

A learning model based on “memory schemata” is presented. The model assumes that knowledge substructures in memory are shared by multiple representations of information from diverse contexts. These substructures, or schemata, are collections of concepts and associations that occur together repeatedly and act as unitary, higher-order concepts. When knowledge is represented in terms of a schema, associations from the schema to additional concepts specify the detailed information for that context. This organization of knowledge entails both costs and benefits for the acquisition and retention of new information that utilizes a schema. The use of a familiar encoding structure facilitates memory access at storage and retrieval time. Multiple uses of the shared structure produce interference among concepts from the various contexts. The predictions of the model were tested in two transfer experiments in prose learning. Experiment l demonstrated the simultaneous effects of both facilitation and interference in the learning of diverse information conforming to a single schema. Recall of information from the schema was a non-monotonic function of schema strength. In Experiment 2 facilitation was preserved while interference was eliminated by increasing the discriminability among competing contexts. Results from both experiments confirmed the predictions of the model.     

The functional equivalence of mental images and errors of movement.

Four experiments are reported demonstrating that mental images are functionally equivalent to physical errors of movement in producing changes in visual-motor coordination, at both central and peripheral levels of the visual-motor system. In the first experiment, subjects in one condition pointed at a target seen through laterally displacing prisms and were instructed to imagine pointing errors identical to those recorded previously for subjects in a separate condition who actually observed their pointing errors. Changes in pointing accuracy during adaptation procedures and visual-motor aftereffects following these procedures for subjects who imagined their errors were proportional to visual-motor shifts and aftereffects for subjects who observed their errors. In the second experiment, these same imagery instructions resulted in identical pointing shifts and aftereffects even in the case where prisms did not displace the target. The third experiment showed that when subjects believe that their mental images of pointing errors do not correspond to their actual pointing errors, pointing aftereffects result that are characteristic of the processing of error information at peripheral, but not central, levels of the visual motor system. The final experiment showed that when subjects do believe that their images of pointing errors correspond to actual pointing errors, but imagine the pointing movement itself in addition to their errors, pointing aftereffects result that are characteristic of the processing of error information at central, but not peripheral, levels of the visual-motor system. Contributions to visual-motor aftereffects from these two levels appear to be additive. Another significant result was that, in the imagery feedback conditions of each experiment, subjects who gave high ratings of vividness to their mental imagery showed the greatest magnitude of pointing aftereffects. These findings establish that mental images for errors of movement can produce stable visual-motor changes that cannot be accounted for simply by subjects' expectations regarding the actual consequences of their actions.     

Lip reading in infants: Attention to speech presented in- and out-of-synchrony

Twelve 10- to 16-week-old infants were presented with nursery rhymes spoken with speech sounds and lip movements in-synchrony and out-of-synchrony by 400 msec. Two observers measured the amount of time the infants did not attend to the two types of stimuli. The results showed that the infants attended significantly less to the out-of-synchrony presentation than to the in-synchrony presentation. This finding was interpreted as an indication that young infants are aware of the congruence between lip movements and speech sounds.     

The role of comprehension in children's observational learning of a syntactic rule

This experiment tested the hypothesis that there is a relationship between children's comprehension of a syntactic form and the effectiveness of modeling in promoting imitation of that form. Nursery and kindergarten children received pretests for both comprehension and production of reversible passive sentences. Children who produced no passive sentences were classified either as high, intermediate, or low comprehenders on the basis of their comprehension test performance. Within each of these three groups, children were randomly assigned either to a modeling or to a no-modeling control condition. Children in the treatment condition heard a model use passive sentences to describe a series of pictures. As predicted, the imitation post-test scores of these children were significantly related to their comprehension pretest scores. No significant relationship between the post-test scores and the comprehension scores of control subjects was detected. Children exposed to the model in all three comprehension groups received significantly higher post-test scores than did their respective counterparts in the no-modeling condition. These results are discussed in terms of the hypothesis that language learning proceeds from comprehension to imitation to production.     

Locus of control and causal attribution for positive and negative outcomes on university examinations

One-hundred-five internal and external locus of control subjects attributed responsibility for their positive and negative outcomes on a university examination. Internal and positive outcome subjects attributed responsibility to internal causal factors while external and negative outcome subjects were more external in their causal attributions. Overall ratings of the four causal components ability, effort, task, and luck were not always in accord with the Weiner model two-dimensional classification.     

Symptomatic cluttering in adults.

Two patients with symptomatic cluttering due to acquired neurological disease are described. One patient suffered a brainstem infarct (stroke), and the other appeared to have a typical clinical picture of multiple sclerosis. Linguistic analysis of the two patients is provided along with a comparison of idiopathic cluttering of childhood. The implications of cluttering as an acquired speech disorder are discussed.     

Cognitive abilities of street children: Low-SES Bolivian boys with and without experience of living in the street

Objectives: This study compared results on cognitive tests measuring nonverbal visualization and reasoning, executive functions, and creativity between 36 boys with experience of living in the street and 31 housed yet socioeconomically equivalent boys, in Bolivia.

Results: The street children scored significantly higher on the creativity measure, which is discussed in relation to contextual relevance. No significant differences were found on the other cognitive tests. Time elapsed after living in the street and drug use were strongly associated with cognition, while age was not. Both groups scored below average compared to Western norms. The results are discussed in terms of the cultural relevance of the tests and the impact of socioeconomic status, stress, and stimulation on cognition.