Conservation of weight is known to be achieved at a conceptual level at about 9 years of age. Infant behavior seems to indicate that between 6 and 18 months of age they develop a sensorimotor form of conservation. (Author/RC)

Based on PhD dissertation submitted to the University of California, Los Angeles.

Research supported by Grants MH-11699-01 and NB-04268 from the U.S. Public Health Service.

Two studies were conducted to examine (1) 1- to 3-day-old infants' imitation of their mothers, and (2) mothers' imitation of their newborn infants. For the infant imitation study, 30 mothers and their infants served as subjects. Two observers stood behind the mother to view the infant's face while the mother presented one of the following…

In this study examining infants' responses to optical expansion, 18 infants between 36 and 61 days old watched expanding shadows that differed in the terminal location of the center of expansion and the number of dimensions undergoing change. Babies consistently rotated their heads upward during expansion of a closed figure when the center of…

Four experiments were conducted to investigate the extent to which infants of different ages respond to facelike drawings on the basis of stimulus complexity and/or resemblance to the human face. Infants' responses to stimulus patterns were assessed using the corneal reflection technique developed by Robert Trantz. In the first two experiments,…

A total of 14 infants participated in this study of the recovery of visual orienting by crossmodal stimulation when no new visual information was present. The locus of the crossmodal stimulation (auditory stimulation) was discriminable to the subject. Infants in three age groups were tested on three occasions each separated by 30 days. No…

This paper introduces and gives a report of the first of a series of studies concerned with the developmental aspects of information processing. The experiments are concerned chiefly with how repeated visual encounters influence infants' attentional preference for what is familiar or unfamiliar and how infants' preference can be affected by…

This paper offers a concise 3-page summary of the results of some investigations of sucking behavior during the neonatal period. This is followed by a page of references and 16 pages of pertinent diagrams and their descriptions. The investigations are the result of an objective technique developed for measuring the nutritive sucking behavior of…

Two experiments are reported in which cardiac habituation and dishabituation to pure tone stimuli were studied in well and malnourished Guatemalan infants. In both studies the magnitude of the orienting response was found to be attenuated or completely absent in infants suffering from nutritional insult. The findings were taken as evidence of a…

This paper is a discussion of the different contexts in which the concept of the infant's state is used in infant research. The infant states discussed are: regular sleep, irregular sleep, drowsiness, alert inactivity, waking activity, and crying. Also included are hunger periods and indeterminate states, those instances in which an infant's state…

The stability of eight attachment behaviors was investigated in two samples of infants. One sample observed at 10 and 14 months of age, the other sample at 14 and 18 months. For each testing period, the infants were observed during two sessions: (a) in the presence of the mother; and (b) before, during, and after a brief separation experience.…

The role of genetic factors in infant response to redundancy was evaluated through observation of the behavior of three sets of same-sex fraternal twins and six sets of same-sex identical twins to combinations of redundant proprioceptive and auditory stimulation. The twins ranged in age from 6 weeks to 24 weeks. One member of each twin set was…

The present study examined infants' reactions to separation from and reunion with their mothers, and attempted to determine if these behaviors were related to the infants' experiences with their mothers at home. The subjects, 60 Caucasian mother-infant pairs, were observed at home two hours on each of two days and in a laboratory setting. The…

The relationship between visual stimulus intensity and directional finger movements was examined in infants of two age groups (16 infants, 10 to 15 weeks old, and 8 infants, 20 to 25 weeks old). Two hypotheses derived from Schneirla's Approach-Withdrawal Theory were examined: (1) that responses of the younger, but not of the older infants, would…