摘要:

AbstractGunn rat dams were tested for differential retrieval of their jaundiced versus non‐jaundiced offspring in 2 experiments. In Experiment 1, in which testing took place every day from Day 1 to Day 8 postpartum, non‐jaundiced pups were retrieved significantly faster than jaundiced pups. In Experiment 2, in which testing took place every other day from Day 1 to Day 15 and the pups were weighed each test day, the order of retrieval of the 4 gender/genotype (jaundiced vs non‐jaundiced) classifications as found in the 1st experiment was replicated and the non‐jaundiced pups tended to be retrieved faster. Heavier pups were retrieved significantly faster than lighter pups, indicating that weight or size may be a cue to differential re

ISSN:0012-1630    

DOI:10.1002/dev.420110104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractRats were enucleated at 28 days of age and were assigned to complex or relatively barren tactile environments for the duration of the experiment. Approximately half of the animals in each group received large, bilateral lesions of the somatosensory cortex when they were 60 days of age, and the remainder underwent sham operations. Twenty days later all groups were tested for the ability to master a series of tactile discriminations. Statistical tests revealed a highly significant lesion effect, but no environment or lesion x environment interaction effects. These sensory discriminative findings stand in contrast to some earlier reports which have shown that environmental complexity provided prior to or following other forebrain lesions can minimize error scores on simple learning tasks.

ISSN:0012-1630    

DOI:10.1002/dev.420110105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractIncubator‐hatched bobwhite quail neonates were tested individually in a variety of single call and simultaneous auditory choice tests involving 6 adult quail vocalizations and a chicken exodus call. The quail showed a high degree of responsiveness (100%) to 3 adult quail vocalizations and significantly less responsiveness (40–50%) to 3 other quail calls and to the chicken exodus call in single call tests. In simultaneous choice tests, the quail were selectively responsive to a call of their own species over the chicken call, and they also showed certain intraspecific preferences. Because of their high degree of responsiveness, coupled with the selectivity of their approach responses, bobwhite quail neonates are ideal for the laboratory investigation of the development of auditory percept

ISSN:0012-1630    

DOI:10.1002/dev.420110106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA time‐sampling procedure was employed to examine the caretaking behavior of male mice housed with lactating females and their litters, and to investigate the effects of the male's presence on the behavior of the female. The incidences of 14 categories of behavior were recorded over 20 hr distributed throughout the period of lactation. The development of litters was monitored by regular weighing. The results show, contrary to earlier findings, that males display just as much caretaking behavior as females. Differences in other forms of behavior can be related to the increased nutritional needs of the nursing mothers. The presence of the male seems to have very little influence on the behavior of the female and no effect at all upon the physical development of the litte

ISSN:0012-1630    

DOI:10.1002/dev.420110107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractIn 3 experiments the performances of light‐reared (LR) and dark‐reared (DR) 90‐day‐old rats were compared on a variety of transfer tests following acquisition of 3 discriminations involving patterns of small squares (dots). Though no significant difference due to rearing condition was found in acquisition of those discriminations consisting of single lines of dots in various orientations, transfer tests did reveal subtle differences in the way LR and DR rats analyze contour information. Significant differences due to rearing were also observed on the acquisition of a complex dot pattern (∇ vs X) and, in spite of overtraining, on subsequent stimulus equivalence tests. Anomalous transfer effects were not observed in any of these test s

ISSN:0012-1630    

DOI:10.1002/dev.420110108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractRats were subjected to pre‐ and postnatal undernutrition by restricting the food intake of their mothers (U); another group of rats was normally fed (N). Each nutrition group was divided into 3 subgroups by varying the degree of environmental stimulation: animals in the Max group were stimulated by handling and enriched rearing conditions; the Min group rats were subjected to social isolation; rats in the control condition (C) were raised under ordinary laboratory conditions. The onset of sexual activity was not affected in the U‐C male rats, but was delayed in both U‐Min and N‐Min rats. Although no difference existed in the age of puberty between the N‐Max and N‐C animals, the U‐Max rats displayed an advancement of puberty by 7 days in comparison to the U‐C rats. Undernutrition did not affect female sexual maturation; however the Max condition delayed this process in both n

ISSN:0012-1630    

DOI:10.1002/dev.420110109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA sequence of 4 experiments examined the effects of prepubertal and adult males on the sexual maturation of young female house mice. The results support 3 conclusions: (1) the presence of a prepubertal male or of urine from prepubertal males does not affect the timing of sexual maturation in young female house mice; (2) the maturation‐accelerating pheromone produced by adult males is present in the bladder urine of intact adult males but is absent from both excreted and bladder urine of castrated males; and (3) young females caged with 7 prepubertal males or with a castrated adult male mature earlier than control females caged alone. Results indicating that the presence of a castrated male leads to earlier sexual maturation of young female mice differ from previous findings. A possible explanation for this contradictory result is based on the ability of young weanling female mice to acclimatize and thermoregulate when separated from the dam and litter‐mates. A model for density‐feedback population regulation in house mice involving pheromones produced by males and females is pres

ISSN:0012-1630    

DOI:10.1002/dev.420110110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractRats reared in isolation have been reported to show increased motor activity; the purpose of the present experiment was to establish whether they also show enhanced exploratory and orienting responses. Rats were reared in isolation or in social groups from Day 20 to Day 45. Subgroups of each rearing condition were either left undisturbed, received daily handling, or received daily handling and were given objects in their cages. From Day 45 all the rats were rehoused in groups of 6, and testing began at Day 73. In a 1st test exploration was measured by the number of contacts with objects placed in the home cage; in a 2nd test exploration was measured by responses to a holeboard; and in a 3rd test orienting was measured by the distraction produced by the presentation of a tone. When tested in novel situations, in contrast to their enhanced motor activity, isolates showed reduced exploration and orienting. This may have been due to a discrepancy between their adaptation level (established during rearing) and their current level of sensory input. In all the tests the isolates showed normal habituation, both within sessions and between sessions. An inability to habituate is not, as has been claimed, a general characteristic of isolates.

ISSN:0012-1630    

DOI:10.1002/dev.420110111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractAn experiment was conducted to examine the effects of neonatal handling and hypothermia on infant physical maturation and growth and on maternal behavior in BALB/c mice. Stringent methodological and statistical controls were employed for experimenter bias and litter effects. No evidence appeared to support claims that neonatal stimulation leads to accelerated physical maturation. Alterations in maternal behavior patterns were found only immediately following hypothermia of pups. Maternal behavior did not correlate highly with offspring maturational rates, but maternal weight and age and pup birth weight were highly predictive of infant physical maturation.

ISSN:0012-1630    

DOI:10.1002/dev.420110112

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420110113

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY