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Biomedical subjects

Louise Barrett

Publications and source records attributed to Louise Barrett.

12 recordsLinked to original sources
PubMed2006

The ecology of motherhood: the structuring of lactation costs by chacma baboons.

1. Data from a long-term study of Papio hamadryas ursinus (L.) in the De Hoop Nature Reserve, Western Cape, South Africa, were used to test the assumptions and predictions of Altmann's model of maternal time budgets. 2. Female baboons' feeding time was below model predictions, and there was no evidence for a consistent increase in feeding time with infant age. In addition, female feeding time was not significantly higher than observed baseline feeding times for nonlactating females. 3. Female baboons reduced activity levels in the first few months post-partum, as reflected in significant increases in resting time, and there was some indication that females lost body mass over the course of lactation. When feeding demand was high, females sacrificed social time, and conserved resting time. 4. Females increased vigilance levels during the first 4 months of infant life and were more vigilant overall during lactation than when nonlactating. There was a negative relationship between feeding time and vigilance, but a positive relationship between resting time and vigilance. 5. Female baboons at De Hoop appear to cope with the energetic costs of lactation by reducing activity levels, although this cannot compensate completely for increased energetic costs. This may not be so much an'energy-sparing' strategy as a response to threats presented by infanticidal males in this population. Females therefore trade-off feeding time against vigilance.

Animals↗
PubMed2006

Indigenous beliefs and attitudes to AIDS precautions in a rural South African community: an empirical study.

BACKGROUND: It was recently hypothesized that indigenous belief systems might have a bearing on attitudes toward HIV/AIDS prevention in Southern Africa. PURPOSE: This article comprises the first empirical test of the hypothesis. METHODS: Participants (n = 407) lived in a remote rural area of KwaZulu Natal, South Africa, and were divided into younger (18-24 years) and older (35-45 years) cohorts. All participants completed a questionnaire measuring Attitudes to AIDS Precautions, indigenous knowledge, indigenous beliefs about ancestral protection, and indigenous beliefs about illness. RESULTS: Indigenous beliefs pertaining to health behavior emerged as multidimensional in both structure and effect. Among older participants, there were significant associations between indigenous belief measures and Attitudes to AIDS Precautions. In this group, a strong belief in ancestral protection was associated with more negative Attitudes to AIDS Precautions, whereas a strong belief in traditional explanations for illness was associated with more positive Attitudes to AIDS Precautions. The indigenous beliefs measures were not associated with Attitudes to AIDS Precautions among younger participants. CONCLUSIONS: The data lend modest support to the hypothesis that indigenous beliefs have a measurable association with attitudes to AIDS prevention, although these associations may be diminishing across generations. Further research, exploring a wider range of indigenous beliefs and focusing on actual precautionary behaviors rather than attitudes, seems merited.

Acquired Immunodeficiency Syndrome↗
PubMed2005

The social nature of primate cognition.

The hypothesis that the enlarged brain size of the primates was selected for by social, rather than purely ecological, factors has been strongly influential in studies of primate cognition and behaviour over the past two decades. However, the Machiavellian intelligence hypothesis, also known as the social brain hypothesis, tends to emphasize certain traits and behaviours, like exploitation and deception, at the expense of others, such as tolerance and behavioural coordination, and therefore presents only one view of how social life may shape cognition. This review outlines work from other relevant disciplines, including evolutionary economics, cognitive science and neurophysiology, to illustrate how these can be used to build a more general theoretical framework, incorporating notions of embodied and distributed cognition, in which to situate questions concerning the evolution of primate social cognition.

Animals↗
PubMed2005

Indigenous representations of illness and AIDS in Sub-Saharan Africa.

Cultures all over the world have evolved illness representations that can accommodate not only new diseases, but also new epistemologies for explaining disease. This paper examines illness representations in Sub-Saharan Africa, and how these have responded to the emergence of AIDS. Indigenous views of illness (particularly STDs) exhibit coherent structure, in which causation, prevention and treatment relate to one another in functional ways. As an STD, an epidemic, and a disease which leads to premature death, AIDS lends itself readily to accommodation into established indigenous representations of illness. Even biomedical views of causation can be readily incorporated into traditional views of how illnesses are caused. However, biomedical and traditional views concerning prevention appear to be in direct conflict with one another, with potentially hazardous consequences. Research exploring the extent to which indigenous beliefs may be influencing people's decisions about safe sex could offer useful insights for AIDS prevention programs.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Fecal cortisol levels in free-ranging female chacma baboons: relationship to dominance, reproductive state and environmental factors.

Savannah baboons are one of the few mammalian species that do not exhibit seasonal reproduction patterns and are therefore ideally suited to study the effect of female reproductive states (cycling, pregnant, lactating) on cortisol levels independent of seasonal factors. Fecal samples from 10 free-ranging female chacma baboons (Papio hamadryas ursinus), collected during a period of 17 months, were analyzed using a steroid-extraction method. Reproductive state had a significant effect on fecal cortisol, with lowest levels found in estrous females. Fertility was not related to fecal cortisol levels; we found no significant differences between samples collected on conceptive and nonconceptive cycles. Environmental factors explained most of the variance of fecal cortisol levels. Cortisol measures were strongly correlated with seasonal differences such as daylight duration, temperature and the amount of time that baboons spent resting. We measured higher cortisol levels during winter months and suggest that this could be related to shorter resting periods and to the cold minimum ambient temperatures at this study site. Finally, we found no relationship between social rank nor the rate of agonistic interactions with basal fecal cortisol levels.

Adaptation, Physiological↗
PubMed2003

Indices of environmental temperatures for primates in open habitats.

Studies of thermoregulation in primates are under-represented in the literature, although there is sufficient evidence to suggest that temperature represents an important ecological constraint. One of the problems in examining thermoregulation in primates, however, is the difficulty in quantifying the thermal environment, since shade temperatures, solar radiation, humidity and wind speed all serve to alter an animal's 'perceived' temperature. Since animals respond to their perceived temperature, we need methods to account for each of these factors, both individually and collectively, if we are to understand the integrated impact of the thermal environment on primates. Here, we present a review of some thermal indices currently available. Black bulb temperatures can account for the effect of solar radiation, with wind chill equivalent temperatures and the heat index providing quantifiable estimates of the relative impact of wind speed and humidity, respectively. We present three potential indices of the 'perceived environmental temperature' (PET) that account for the combined impact of solar radiation, humidity and wind speed on temperature, and perform a preliminary test of all of the climatic indices against behavioural data from a field study of chacma baboons ( Papio cynocephalus ursinus) at De Hoop Nature Reserve, South Africa. One measure of the perceived environmental temperature, PET2, is an effective thermal index, since it enters the models for feeding and resting behaviour, and also accounts for levels of allogrooming. Solar radiation intensity is an important factor underlying these relationships, although the wind chill equivalent temperature and humidity enter the models for other behaviours. Future studies should thus be mindful of the impact of each of these elements of the thermal environment. A detailed understanding of primate thermoregulation will only come with the development of biophysical models of the thermal characteristics of the species and its environment. Until such developments, however, the indices presented here should permit a more detailed examination of the thermal environment, allowing thermoregulation to be given greater precedence in future studies of primate behaviour.

Animals↗
PubMed2003

Primate cognition: from 'what now?' to 'what if?'.

The 'social brain' hypothesis has had a major impact on the study of comparative cognition. However, despite a strong sense, gained from both experimental and observational work, that monkeys and apes differ from each other, we are still no closer to understanding exactly how they differ. We hypothesize that the dispersed social systems characteristic of ape societies explains why monkeys and apes should differ cognitively. The increased cognitive control and analogical reasoning ability needed to cope with life in dispersed societies also suggests a possible route for human cognitive evolution. This hypothesis is supported by behavioural and neurobiological data, but we need more of both if we are to fully understand how our primate cousins see the world.

Journal Article↗
PubMed2002

Facial attractiveness judgements reflect learning of parental age characteristics.

Mate preferences are shaped by infant experience of parental characteristics in a wide variety of species. Similar processes in humans may lead to physical similarity between parents and mates, yet this possibility has received little attention. The age of parents is one salient physical characteristic that offspring may attend to. The current study used computer-graphic faces to examine how preferences for age in faces were influenced by parental age. We found that women born to 'old' parents (over 30) were less impressed by youth, and more attracted to age cues in male faces than women with 'young' parents (under 30). For men, preferences for female faces were influenced by their mother's age and not their father's age, but only for long-term relationships. These data indicate that judgements of facial attractiveness in humans reflect the learning of parental characteristics.

Adult↗