TRAINING CONSERVATION OF QUANTITY (LIQUIDS) IN WEST AFRICAN (BAOULE) CHILDREN

A developmental ‘lag’ is found in the Conservation of Quantity (Liquids) in a sample of 73 rural, schooled Baoulé children (Ivory Coast, West Africa) aged 7 to 14 years. This study was designed to investigate if this ‘lag’ could be reduced or bridged through training and whether it could be attributed to differences in ‘performance’ or in ‘competence’. A sub-sample of 28 children aged 7 to 9 years was divided into two matched groups, one being trained for Conservation of Liquids and the other for Class Inclusion (Lavallée and Dasen in press). Statistically significant training effects were observed, which generalized to other concrete operational concepts and remained stable over at least one month. Since no ‘actualization’ or very fast learning occurred, the ‘lag’ was attributed to differences in competence; the training was sufficient to bridge the developmental lag.     

Effects of differential reinforcement and task difficulty on preschoolers' compliance with teacher instructions

Preschool children in day schools were given instructions to complete certain tasks. Four tasks were given of two types and two levels of difficulty. In each condition compliance with at most one instruction (one task) was reinforced. In two similar experiments, with six children, general results were: compliance with easy tasks was maintained without reinforcement when any task compliance was reinforced; compliance for hard tasks remained high only when that specific task was reinforced. Thus, generalization of compliance with instructions varied with task difficulty. The setting and procedure for both studies were designed to reduce possible coercive features of laboratory studies of generalized performance. Results show generalized performance can occur under naturalistic conditions. The effect of effort, as a response characteristic affecting generalized performance, is discussed.     

Conditioning of striatal dopamine metabolism with methadone,morphine or bulbocapnine as an unconditioned stimulus

Psychotropic drugs such as methadone, morphine and bulbocapnine produce increments in dopamine metabolism as an unconditioned reflex. When a buzzer noise is used as a conditioned stimulus (CS) with these drugs as unconditioned stimuli, the buzzer CS acquires the properties of the drugs in increasing dopamine metabolism. These results suggest that the brain, like other visceral organs, can be conditioned in terms of neurotransmitter release or metabolism.     

Acquired aphasia in children and the ontogenesis of hemispheric functional specialization.

We have described a series of 26 cases of cortical lesions in children from $\text{3}\text{1}\text{2}$ to 15 years of age (17 left-sided, six right-sided, three bilateral), in which 19 had varying degrees of language disturbance. We have attempted to establish the nature and evolution of these aphasic disorders, and have compared our observations to those previously published. Our analysis appears to indicate a relative hemispheric equipotentiality which permits the transfer of language representation to the opposite hemisphere in the case of a unilateral lesions in childhood. This conclusion, however, has at least the appearance of being in conflict with other reported findings, viz., those deriving from psychometric testing of subjects with unilateral perinatal lesions; and those concerning studies of fetal and newborn brains which suggest a very early, if not innate, hemispheric specialization.The fact of this discrepancy has lead us to reconsider the concept of a critical period as defined by Lenneberg. In this respect, we have also discussed the possibility of a partial transfer of language representation, of an intrahemispheric reorganization by intact “uncommitted” areas (P. Goldman), and finally, the need for an adequate stimulus during a given period in order for a preformed area to become functional.