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Biomedical subjects

H Hayne

Publications and source records attributed to H Hayne.

18 recordsLinked to original sources
PubMed1998

The timing of food availability affects growth in chicks.

Three experiments challenged the ability of domestic chicks to grow normally by differentially restricting when and for how long food was available. In Experiments 1 and 2, food was available for six 1-hr, three 2-hr, two 3-hr, or one 6-hr (a.m., p.m.) periods/day over the first 3 posthatch weeks. Control groups received continuous access to food. In Experiment 3, different amounts of light surrounded the 6-hr feeding period. In Experiments 2 and 3, chicks composed their own diets from separate sources high in protein or carbohydrate. Except for the single 6-hr meal preceding dark, large meals at other times of day impaired growth--primarily because chicks consumed insufficient dietary protein and ate less earlier in the light phase. We conclude that both the amount eaten and the proportion of the diet consumed as protein at given times of the day are phylogenetically acquired strategies that fit the omnivorous, diurnal chicken to its niche, independent of its momentary requirements, and appear early in development.

Analysis of Variance↗
PubMed1997

Behavioral thermoregulation in chicks: the best nest.

The ability of prehomeothermic chicks to thermoregulate behaviorally was studied in chicks with continuous access to heated nests, running wheels, and separate sources of high and low protein. In Experiment 1, cold-reared groups with heated or unheated transparent nests ate the same amount and selected the same dietary fractions, but chicks with heated nests ran less and grew faster. Despite this, groups maintained normal body temperatures. In Experiment 2, chicks were cold- or warm-reared with heated or unheated painted nests, or no nests. Cold-reared chicks with heated nests spent most of their time in them. They selected diets containing a higher protein:carbohydrate ratio than cold-reared chicks with unheated nests but ate less, thereby consuming less absolute protein and growing more slowly. Despite differences in growth, intake, and dietary choice, all chicks maintained normal body temperatures. These data reveal that behavioral thermoregulation has a privileged status for chicks over the first 3 weeks of life. Prehomeothermic chicks exercise complex and effective solutions to energetic challenges when offered behavioral options that simulate those available in nature.

Adaptation, Psychological↗
PubMed1996

Diet selection by chicks.

Seven experiments with 324 chicks tested their ability to select a nutritionally adequate diet from separate sources of purified casein and various supplements, including gelatin (a source of two amino acids), a gelatin-creatine mixture (a source of three amino acids), and fiber (nonnutritive bulk). Nonselecting controls consumed the basal purified-casein diet or a supplemented purified-casein diet. Chicks in all selection conditions composed diets that yielded normal intake, normal body temperature, normal activity, and the maximum growth possible for their intake. They also selected components in the same percentages as in premixed diets. In all instances, their selection was nonrandom and regulated. What chicks included in their diet depended on what else was available. Although the specific percentage taken from each dietary component varied across different selection alternatives, these differences affected neither intake nor growth. Selection, per se, incurred a caloric cost. Chicks selecting from fractions of a corn-and-soy diet offset this cost by increasing intake compensatorily, but chicks with a purified-casein fraction did not, suggesting that some unspecified property of casein placed a ceiling on its intake. These findings unequivocally demonstrate that immature chicks not only can self-select nutritionally adequate diets, but can do so with unexpected precision by exploiting different but equally successful strategies.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Learning and retention of conditioned aversions by freely feeding chicks.

The present experiments assessed poison-based aversion learning and retention in freely feeding and drinking domestic chicks whose drinking water was colored blue and adulterated with LiCl for a 24-hr period. The amount of LiCl self-administered by 11-day-old chicks and their subsequent avoidance of unadulterated water of the same color was examined. The results of four experiments demonstrated that chicks self-administered large and often lethal doses of the LiCl solution. Chicks subsequently avoided blue water during two-bottle preference tests administered 3 to 7 days but not 14 days after exposure. These data indicate that neophobia alone is insufficient to prevent nondeprived chicks from ingesting large quantities of a toxin during their initial encounter with it. The lack of long-term retention in the present experiments indicates that naturally occurring aversions based on visual and illness cues, while effective in the short term, may not be a major factor in the choices made by freely feeding and drinking chicks over the long term.

Animals↗
PubMed1996

Adults' understanding of young children's testimony.

In many legal settings, judges and jurors must gain an understanding of a crime solely on the basis of a child's testimony. In the present experiment, the authors examined adults' ability to understand young children's accounts of a past event. Adults were given a transcript of an interview with a 3- and a 6-year-old child. In addition, half of the adults were given a summary of the event (informed) and half were not (naive). All adults were asked to extract as many details as possible from the transcripts. Naive adults were also asked to write a paragraph summarizing what happened during the event. Overall, adults gleaned more information from transcripts of 6-year-olds than from transcripts of 3-year-olds. Furthermore, naive adults were more accurate than informed adults. The authors concluded that adults' ability to understand children's testimony increases as a function of the child's age and may be impaired rather than enhanced by additional sources of information.

Adolescent↗
PubMed1995

The organization of reactivated memory in infancy.

The specificity of memory retrieval by 3-month-old infants was examined in 3 experiments. All infants were trained in the mobile conjugate reinforcement paradigm to kick their feet to produce movement in an overhead crib mobile and were tested 2 weeks later. 24 hours prior to the test, subjects received a 3-min reminder treatment. The results of Experiment 1 demonstrated that only the moving training mobile alleviated forgetting after the 2-week retention interval; forgetting was not alleviated by exposure to the stationary training mobile or to the mobile stands and ribbon alone. The results of Experiments 2 and 3 demonstrated that, once retrieved, the reactivated memory was highly specific to the conditions of original training. Furthermore, the memory attributes that were the last to be forgotten (e.g., the general or global features) were the first to be retrieved following the reminder treatment. Conversely, those memory attributes that were forgotten first (e.g., the specific or local details) were the last to be retrieved. These findings have important implications for infant memory retrieval, reminiscence, and infantile amnesia.

Child Development↗
PubMed1992

Developmental constraints on the expression of behavioral and heart-rate orienting responses: II. The role of ambient temperature.

The effect of ambient temperature on the expression of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in rats 1-18 days of age. There was no effect of ambient temperature on the behavioral orienting responses at any age. Ambient temperature did influence the expression of the heart-rate orienting response and did so differentially as a function of age. The implications of these findings for developmental models of attention and cognition are discussed.

Animals↗
PubMed1992

Developmental changes in the duration of attention to unfamiliar stimuli in the rat.

The purpose of the present study was to examine developmental changes in the duration of attention to novel auditory stimuli in rats from infancy to adulthood. In all experiments, the cardiac component of the orienting response was used as the index of attention. In the first experiment 16-, 23-, 30-, and 75-day-old rats were exposed to a novel auditory stimulus for 60 s. Animals of all four ages exhibited a marked decrease in heart rate in response to this stimulus. Although there were no significant effects of age on the magnitude of the cardiac response, there were dramatic developmental differences in the persistence of the response. The 16-day-olds maintained a decrease in heart rate for the entire stimulus period, whereas heart rate returned to baseline in the 75-day-olds after only 40 s. The duration of the cardiac response of the 23- and 30-day-olds was between these extremes. In Experiments 2A and 2B the effect of stimulus complexity on duration of the cardiac response was examined. Increasing stimulus complexity prolonged the deceleratory response in the 30-day-olds (Experiment 2A), and decreasing stimulus complexity decreased the duration of the cardiac response in the 16-day-olds (Experiment 2B). The results of these experiments were discussed in the context of Cohen's and Porges's two-phase theories of attention. The findings demonstrate that the initial attention-getting or reactive phase of attention did not change with age, but that the duration of the attention-holding or sustained phase decreased substantially during development.

Acoustic Stimulation↗
PubMed1991

Developmental constraints on the expression of behavioral and heart-rate orienting responses: I. The role of cardiosomatic coupling.

The ontogeny of behavioral and heart-rate orienting responses to a novel olfactory stimulus was examined in three experiments. The results of Experiment 1 demonstrated that behavioral responses to the olfactory stimulus were observed as early as Day 1, although heart-rate deceleration in response to the stimulus was not observed until Day 9. In Experiment 2, bradycardia was observed in 6-day-old pups if stimulus-elicited motor activity was reduced with haloperidol. Thus, the developmental asynchrony in the expression of behavioral and heart-rate orienting responses was due, at least in part, to cardiosomatic coupling in the very young animal. The results of Experiment 3 demonstrated that although cardiosomatic coupling interferes with the expression of the heart-rate orienting response very early in development, it has increasingly less impact over the course of the preweaning period.

Aging↗
PubMed1991

Infant memory for place information.

The present studies were designed to examine the role of place cues in memory retrieval during early infancy. Three-month-old infants were trained to move a mobile by kicking. Two weeks later, memory retrieval was disrupted if they were reminded in a location or place different from where they had been trained, but not if they were reminded in the same place (Experiment 1A). The same result was obtained even though highly salient cues in their immediate visual surround remained unchanged during reminding (Experiments 1B and 1C). No disruption was seen, however, when retrieval was cued in a different place after only 1 day (Experiment 2). These findings unequivocally demonstrate that infants as young as 3 months encode incidental information about the place where an event occurs and suggest that early memories are buffered against retrieval in potentially inappropriate contexts over the long term.

Arousal↗
PubMed1990

The effect of multiple reminders on long-term retention in human infants.

The present series of experiments compared the effects of single- and multiple-reminder procedures on the long-term memory of 3-month-old human infants. Subjects were trained in the mobile conjugate reinforcement paradigm, and the reminder treatment was a brief, noncontingent exposure to the moving mobile. In Experiment 1, independent groups received one or two reminder treatments during the 3 weeks following the conclusion of training. Independent groups were tested 1, 3, 7, 14, or 22 days following the last (or only) reminder (i.e., 21-42 days after the end of training). Although retention was equivalent 1 day after one or two reminder treatments, subsequent retention was significantly prolonged by the second reminder treatment: infants receiving a single reminder treatment demonstrated no evidence of retention 7 days after the reminder, but infants receiving two reminder treatments demonstrated perfect retention as long as 14 days later. In Experiment 2, retention was observed 14 days after two reminder treatments irrespective of whether the treatments were presented during the first and second or the third and fourth weeks following the conclusion of training. In Experiment 3, the effect of three reminder treatments on retention was examined. Although retention was excellent when infants were tested 1 day after the third reminder, retention after longer intervals was no better than that observed after a single reminder treatment.

Arousal↗
PubMed1990

Roles of function, reminding, and variability in categorization by 3-month-old infants.

The roles of function, reminding, and exemplar variability in categorization of a physically dissimilar object were studied with 3-month-old infants trained to move a crib mobile by kicking. Performance on a transfer test with a motionless novel object provided evidence of categorization. In Experiments 1 and 2, infants, like adults, initially categorized novel objects on the basis of physical appearance, but only if trained with multiple exemplars, after delays of 1 and 7 days. In Experiment 3, prior knowledge of an object's functional properties overrode physical dissimilarity as the basis for categorization and enabled reminding of the classification response 2 weeks later. In Experiment 4, postevent contingency information overrode physical and functional properties as the basis for categorization. These findings indicate that expectations and goals influence infants' category decisions and raise the possibility that infants of 3 months respond by analogy.

Arousal↗
PubMed1989

Amount of training and retention by infants.

In studies of animals and adult humans, more training typically leads to better retention. The generality of this finding was assessed in two studies with human infants in which amount of training was manipulated in two different ways. In the first study, 3-month-olds were trained for either 1, 2, or 3 sessions, each 9 min long; in the second, they were trained for a single session that was either 6, 9, 12, or 18 min long. Retention of independent groups was measured after delays ranging from 1 to 21 days. In both studies, different amounts of training did not yield group differences on any of the standard measures of acquisition or after a retention interval of 1 day. After intervals of a week or longer, however, more training led to better retention. Across studies, the long-term retention of groups that were trained for the same amount of time differed. We speculate that subjects learn different things in these two training regimens.

Arousal↗
PubMed1987

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↗
PubMed1986

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↗
PubMed1985

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↗
PubMedDate not supplied

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↗