Reactivation of infant memory: implications for cognitive development.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
H Hayne
Publications and source records attributed to H Hayne.
Categorization and memory retrieval by three-month-olds.
84 3-month-olds were tested in 3 studies of the acquisition and long-term retention of category-specific information. Infants who were trained with a perceptibly different member of an alphanumeric category on each of 3 days generalized responding to a novel instance of the original training category but not a novel member of a novel category during a 24-hour novelty test. 2 weeks later, when infants displayed no evidence of remembering their prior training experience, categorization was reinstated if a novel exemplar from the original training category was used as the retrieval cue in a memory reactivation procedure. A novel exemplar from a novel category was not an effective retrieval cue. The effectiveness of the category-specific retrieval cue was a function of its physical similarity to the individual exemplars encountered during training, not testing. The background against which the alphanumeric exemplars were displayed during training was not an effective retrieval cue in either the 24-hour novelty test or the memory reactivation procedure, indicating that all invariant stimulus attributes do not contribute equally as category cues. These data are the first to document retention of category-specific information after extended intervals. A popular account of categorization holds that infants abstract invariant features from individual exemplars and form a schema or distinctive memory representation of these shared features against which subsequent exemplars are compared. The present data provide support for a more parsimonious account of categorization, based on the retrieval of information about individual exemplars, that does not require an assumption of prototype formation.
Arousal↗
Ambient temperature effects on energetic relations in growing chicks.
The effects of different ambient temperature conditions on the diet selection, intake, growth, body temperature, and activity of immature domestic chicks were assessed in two experiments. In Experiment 1, the ambient temperature either remained warm during both the light and dark phases of the photoperiod, as is characteristic in laboratory settings, or was warm during the light phase and cold during the dark phase. The latter condition reflects the daily temperature pattern in natural settings. Chicks exposed to low nocturnal ambient temperatures had lower body temperatures in both phases of the photoperiod, were less active, ate more, selected a higher percentage of carbohydrate in their diets, and grew faster but were less feed-efficient than warm-reared controls. In Experiment 2, the ambient temperature was either cool in both phases of the photoperiod or cool in the light phase and warm in the dark phase. Chicks reared continuously in the cold had lower body temperatures, selected a high-carbohydrate diet, and grew faster, but both rearing groups were relatively inactive. These results show that an animal's body temperature, diet composition, food intake, feed efficiency, and activity reflect its 24-hr energy requirements and are a part of a general strategy of maximizing energy income and minimizing energy expenditure in response to energetic challenges to growth.
Animals↗
Specificity in the reactivation of infant memory.
In three experiments the specificity of an effective reactivation stimulus, or reminder, was examined. Two weeks after learning to produce movement in a crib mobile by footkicking, 3-month-old human infants showed no retention of the response-reinforcer contingency. A reactivation procedure 24 hours prior to the long-term retention test was effective if the reminder was a brief noncontingent exposure to the original 5-component training mobile or a mobile containing one novel substitution. When more than one novel component were substituted into the original mobile, the reminder was ineffective. This was predicted by the discrimination function 24 hours following training. A reminder containing only a single familiar (predictive) component and four novel ones was also moderately effective. In subsequent studies, we explored different interpretations of the reminder specificity effect. We hypothesize that reminder specificity is of particular adaptive value for developing organisms in providing a buffer against memory retrieval in inappropriate contexts.
Cues↗
The effect of prenatal alcohol exposure on attention in the rat.
The effect of prenatal exposure to alcohol on the development of basal heart rate and on the elicitation and habituation of the heart rate orienting response was examined in three experiments with rats. In all experiments, Etoh dams consumed large, daily amounts of alcohol and their weight gain during pregnancy was less than that of ad lib or pairfed dams. In addition, Etoh-exposed pups weighed less and grew more slowly than their ad lib or pairfed counterparts. Although prenatal exposure to alcohol had a significant effect on the ontogeny of basal heart rate, there was no effect on the magnitude of the heart-rate response to a novel olfactory stimulus or on habituation of the heart-rate response to that stimulus. Implications of the present findings for models of alcohol-induced attention deficits are discussed.
Animals↗
Developmental changes in imitation from television during infancy.
Infants' (N = 276) ability to learn from television under seminaturalistic conditions was examined in five experiments with 12-, 15-, and 18-month-olds. In all experiments, an adult performed a series of specific actions with novel stimuli. Some infants watched the demonstration live, and some infants watched the same demonstration on television from prerecorded videotape. Infants' ability to reproduce the target actions was then assessed either immediately or after a 24-hour delay. Infants of all ages exhibited imitation when the actions were modeled live. There were age-related and task-related differences, however, in infants' ability to imitate the same actions modeled on television. The role of perceptual, attentional, and cognitive development in the ability to learn from television is discussed.
Child Development↗