Mothers of 232 pairs of twins were interviewed periodically about the similarities and differences in behavior displayed by their twins during infancy and early childhood. (Authors)

Based on 25 white middle-class infants from 9 to 12 months of age, the earliest manifestation of obedience to appear was a simple disposition to comply with maternal commands and prohibitions, independent of efforts to train or discipline the baby. (Authors/RY)

Eighty middle-class and 80 lower-class boys were tested on a visual and a verbal task under 3 conditions designed to modify an impulsive tempo." (Author)

Four hypotheses were derived from the proposition that positive self-concept is due partly to an ability to utilize self-initiated verbal reinforcement. (Authors)

Intergroup attitudes were assessed in European American 1st-grade (M=6.99 years, SD=0.32) and 4th-grade (M=10.01 years, SD=0.36) children (N=138) attending ethnically homogeneous schools to test hypotheses about racial biases and interracial friendships. An Ambiguous Situations Task and an Intergroup Contact Assessment were administered to all…

Subjects from urban and rural Yucatan were tested on a short-term and incidental memory task. Urban subjects were in school, whereas most rural subjects were not. Results indicated that formal schooling is an important factor in the development of mnemonic skills in short-term memory. (ST)

Implication of findings for designing an introductory mathematics curriculum are discussed. (Authors)

Results suggest that the human infant's response to visual stimulation undergoes change during the neonatal period. (Authors)

Results appear to indicate that the belief systems of the young child about the attributes of a stimulus person can be altered extensively by introducing characteristics completely unrelated to these attributes into the semantic representation of that person. (Authors)

The relation between maternal presence and infant's vocalization depended upon the infant's state: when the infant was in the active awake state, he vocalized less in the presence of the mother than when alone, thus indicating that the majority of early vocalizations are associated with a non-social situation. (Authors/RY)

An experiment was conducted comparing the effectiveness for producing response inhibition of high- and low-intensity physical punishment and elaborated verbal punishment when punishment was delivered either early or late in a response sequence. (Author)

Infant reaction to adult speech was studied through frame-by-frame analysis of sound films. Infants' actions were found to be synchronized with the organized speech behavior of the adults in his environment. (ST)