The hypothesis of less direct interaction between hemispheres in young children was supported by a behavioral test. Fabric samples were compared with either the same hand (same hemisphere) or with opposite hands (between spheres). (Author/HM)

Reports bita-Adrenergic antagonists injected into rats trained in a passive avoidance task produced time-dependent and dose-dependent decreases in retention of the task. Results were stereospecific and reversed by norepinephrine. (SL)

Discusses research on mechanisms that determine the temporal properties of the retrieval of information, represented in long-term memory as a network of associations among concepts. A theory is developed concerned with processes leading from presentation of a probe to levels of activation in the network. (JN)

Discusses current learning theories, indicating that though many psychologists and ethologists now agree on using a mechanistic approach, some linguists doubt its adequacy. Implications of research on the mollusk "Aplasia" to understand the learning process are included. (JN)

Considers the definition of learning as usefully applied to lower animals in instances of trained food-aversion behavior as a viable instance of associative learning. (SL)