摘要:

AbstractExperimental phenylketonuria was induced in male rats by daily injections of α‐methylphenylalanine and phenylalanine on postnatal Days 3–31. Beginning at 8 weeks of age, the animals were subjected to a test of observational learning followed by a test of latent learning (two tests of “advantageous” learning). The animals subjected to the PKU treatment early in life showed significant learning deficits in both tests. The importance of these studies lies in the fact that unlike conventional tests of learning, tests of advantageous learning are sensitive to the kinds of biological insults which cause mental retardation in humans. This differential sensitivity evident in studies of animal models of cognitive pathology is analogized to the areas of dysfunction which characterize human mental retardation. Suggestions for the development of appropriate models of intellectual development of appropriate models of intellectual development

ISSN:0012-1630    

DOI:10.1002/dev.420170202

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

年代:1984

数据来源: WILEY

摘要:

AbstractA “pecking” arrow releases and directs pecking by neonatal chicks. Distinctive stimuli placed on or near the tip of the moving arrow lead to pecking that is selectively directed to matching stimuli. A total of 3 min of exposure to such modeling conditions results in remarkable persistence of imitative behavior. Matching stimuli are preferentially pecked 3 days later after three intervening tests without modeling. In contrast to the sensitive period for filial imprinting within the first 3 days posthatch, age of chick at training has no permanent effect on the development of pecking preferences. If anything, filial imprinting inteferes with released‐directed pecking, suggesting that separate processes are in v

ISSN:0012-1630    

DOI:10.1002/dev.420170203

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

年代:1984

数据来源: WILEY

摘要:

AbstractIn order to test the spatial competence of preschool infants, two groups, aged 2 years and 4 years, were tested on a version of the “radial maze” task. They were required to obtain a chocolate sweet from each of eight identically labelled positions in an unfamiliar room. Four‐year‐olds accomplished this with considerable accuracy, rarely revisiting previously sampled positions. Two‐year‐olds performed marginally above chance. Variants of the task were employed, including rotation of the room configuration so that labelled positions were rendered ambiguous with respect to all other environmental stimuli. The latter caused a marked fall in performance in those infants that had been scoring above chance. By these criteria, infants clearly possess a form of intuitive “spatial memory” that is likely to mature during the second and third years. Parameters of performance were remarkably similar to those seen in comparable studies with nonhumans. It is likely that hippocampal development in early infancy underies this evolving skill, assuming cross‐species similarity in the organization of spatial behavior, and that locomotor competence is required fo

ISSN:0012-1630    

DOI:10.1002/dev.420170204

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe qualitative and quantitative changes in behavioral development in the prenatal and perinatal periods have been insufficiently studied. We observed the occurrence of spontaneous body movements in three strains of mice (ICR, C3H, and BALB) and the pulse counts measured by EMG activity in the ICR strain. Simple body movement first appeared at the 14th day of gestation of the 19‐day gestation period normal for mice. During the prenatal period, fetal movements changed from simple movements to complex and coordinated movements. Differences in the timing of the development of these movements were not found in the three strains of mice. During the perinatal period, the three kinds of simple movement decreased. This decrease was affected by the onset of pulmonary respiration after delivery. The time span of spontaneous movement did not change during the perinatal period, while the pulse counts measured by EMG activity increased with ag

ISSN:0012-1630    

DOI:10.1002/dev.420170205

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

年代:1984

数据来源: WILEY

摘要:

AbstractRat mothers whose pups have been removed show greater plasma corticosterone elevations when the pups are shocked and returned in a wire‐mesh basket that when only the wire basket is returned. For mothers housed with an adult male or virgin female, this differential adrenocorticoid responsiveness between the shocked‐pup and empty‐basket conditions was not observed unless the adult partner was removed 18 hr before testing. Nonlactating adults housed with pups and mother for up to 2 weeks exhibited corticoid elevations equivalent to the shocked‐pup and empty‐basket conditions whether tested with the mother or 18 hr after her removal. These results indicate that the differential pituitary‐adrenal responsiveness that female rats show to pup cues during lactation cannot be accounted for by the length of the mother's exposure to pups, and, further, that this relative responsiveness during lactation appears to be largely due to the suppression of adrenocorticoid reactivity to a nonsocial environmental

ISSN:0012-1630    

DOI:10.1002/dev.420170206

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

年代:1984

数据来源: WILEY

摘要:

AbstractNorway rat pups, 15 days of age and older, huddle preferentially with members of their own species. This normal filial response can be reassigned, however, by altering the olfactory characteristics of the mother. The present series of experiments was designed to isolate those aspects of maternal stimulation that establish the filial huddling preferences of rat pups. Results of two‐choice huddling tests indicated that daily, 4‐hr exposures to a perfumed foster dam induced filial preferences for odors associated with maternal care. Similar effects were also achieved with equal amounts of “mere exposure” (familiarization) to odors. Different kinds of odor‐experience pairings were evaluated with a within‐subject regime of alternating, daily exposures. It was found that preferences induced by maternal contact are stronger than those resulting from familiarization. We rejected the hypothesis that the nursing relationship is necessary or contributory factor in the establishment of the rat's filial attraction; preferences for odors associated with a nonlactating foster mother were as strong as those derived from maternal contact that included nutritive foster mother were as strong as those derived maternal contact that included nutritive nursing. Contact interactions with an inanimate, warm, scented tube induced preferences as strong as those induced by maternal care. It was concluded that thermotactile stimulation during mother‐young interactions induces olfactory preferences in the

ISSN:0012-1630    

DOI:10.1002/dev.420170207

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

年代:1984

数据来源: WILEY

摘要:

AbstractInfant gerbils were deprived of food by removing their mother from the cage for 3 hr on alternate days, during which time they remained with their father. These infants were compared with a control group which remained with their other while the father was removed. Litters lost weight when deprived of food but they received similar levels of parental care, warmth, and tactile stimuli to those of nonfood‐deprived litters. There were no significant effects on the vocalizations of the young when tested either in isolation or in the nest with other pups. This apparent absence of a mode of communicating nutritional sate is discussed with reference to normal interactions between adults and the litter and the role of vocalizations produced in response to heat los

ISSN:0012-1630    

DOI:10.1002/dev.420170208

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

年代:1984

数据来源: WILEY

摘要:

AbstractInfant sensorimotor and social skills, playfulness, and nonplayful behaviors were measured in common marmosets from 6 to 22 weeks old. Different measures of skill showed a low concordance, implying that skill is a multiple rather than unitary attribute. Significant correlations were found between the amount of social play infants performed from 11 to 13 weeks of age and their performance at 14 weeks in (1) competitive food tests with their mothers, and in (2) their ability to negotiate an obstacle for a food reward. Significant correlations were also found between these skills and nonplayful behaviors, however comparable analyses at other ages revealed few significant correlations, suggesting that the association between social play and skills is restricted to the age when infants are rapidly becoming independent of their caregivers both for locomotion and food. Age‐specific correlations occurred between changes in levels of skills and both playful and nonplayful behavious. Our results are consistent with the hypothesis that social play promotes the development of skills, but alternative explanations are possibl

ISSN:0012-1630    

DOI:10.1002/dev.420170209

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

年代:1984

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420170201

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

年代:1984

数据来源: WILEY