Acoustic-optical correspondences and auditory-visual coordination in infancy.

Research on auditory-visual coordination is reviewed, and the following hypothesis is elaborated: The roots of perceptual development are biologically determined perceptual functions that serve information gathering and information processing. Early in infancy, these functions are influenced both by spatial and temporal factors and by formal correspondences between optical and acoustic information; more specifically, spatiotemporal properties constrain information gathering, and optical-acoustic correspondences facilitate exploration and processing. As a result, the infant learns the association between particular acoustic and optical aspects of objects and events. A formal presentation of spatial and temporal properties is outlined. (French abstract) (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Water-intake volume regulation in the rat: Schedule-induced drinking compared with water-deprivation-induced drinking.

Hungry rats drink extremely large amounts of water when they are intermittently fed small amounts of food (schedule-induced polydipsia). The present 5 experiments examined whether such animals are motivated to drink for long durations, to ingest large amounts of fluid, or to do both. When drinking-tube apertures were decreased to slow the rate of water ingestion, each of 8 female Sprague-Dawley rats spent more time drinking than when larger apertures were used (averages of 11.5 vs 7.8 min, respectively). The mean volumes ingested were not different. These equal volumes were generated by adjustment of each drink duration in accordance with ingestion rate even during the first few drinks of the sessions and when the drinking tubes were frequently switched (every 1–3 min) during the sessions. During drinking induced by water deprivation when food was concurrently available, restriction of the tube apertures reduced intake volumes by 18–29%. However, when food was not concurrently available during water-deprivation-induced drinking, regulation of intake volumes was comparable with that found during schedule-induced polydipsia. Data pose difficulties for theories that ascribe a crucial role to the motor aspects of schedule-induced drinking. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of linear probing with buckets

Consider a random-access file which consists of a given number of buckets. Each bucket contains a fixed number of slots. Storage and retrieval of records are performed using linear probing. The probabilities underlying the behavior of this addressing system are determined, and the relevant performance measures are derived.     

Birth order and age differences in early sibling roles.

76 2-child families were assigned to 1 of 3 cohorts that differed in the 2nd-born's age at an initial home visit (5, 11, or 17 mo). The families were seen again 6 mo later. Children were rated by their mothers on 9 sibling role qualities and were videotaped interacting in structured situations. First- and 2nd-borns were seen to fulfill different roles, e.g. mothers rated 1st-borns lower than 2nd-borns on identification but higher on help. The differences between the 2 children on some aspects of sibling roles (e.g., identification) did not change with their ages. Yet other aspects (e.g., help) became increasingly similar, and such changes were attributable to the baby's development. Children's behavior in the structured situations also changed. Some changes were attributable to the baby growing older, whereas others were attributable to the older sibling's or to both children's development. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)