Individual Behavioral Characteristics Research Articles

Continued risk taking behaviour and seroconversion in HIV antibody tested individuals

Abstract Abstract The aim of this study was to identify behavioural characteristics of individuals placing themselves at risk for HIV infection. Subjects were almost exclusively gay men attending an AIDS centre in Sydney between 1985 and 1988, who were HIV antibody negative on first testing. Individuals who seroconverted during this study were found to have significantly more partners and tended to engage in unprotected receptive anal intercourse, compared to seronegative controls. Seroconversion was not attributed to breakage of condoms or contact with known HIV antibody positive partners in this study.

Acute and conditioned blood pressure changes in relation to social and psychosocial stimuli in rats

The naturally occurring tendency to compete with other rats for territorial space has been used to study individual behavior characteristics and blood pressure reactivity to social stimuli in adult male TMD-S3 rats. The competitive characteristics of the individual rats are consistent in two different social situations (victory and defeat). Blood pressure responses during the victory of home territory rats over intruders was more pronounced in the more competitive animals. In addition to defeat by a trained fighter rat, the experimentals were also psychosocially stimulated by the fighter while it was confined in a small wire mesh cage. The blood pressure response to this event was enhanced by the prior defeat of the test animal by the one now confined to the small cage. This response was more pronounced in competitive rats. This approach has potential as an animal model of etiological processes in socially induced hypertension.

Foraging patterns of yellow-bellied marmosts: role of kinship and individual variability

Two colonies of yellow-bellied marmots (Marmota flaviventris) at an elevation of 2900 m in Colorado were studied to elucidate the role of various behavioral and ecological factors as determinants of spatial foraging patterns. The locations of known individuals were periodically recorded. These locality data were plotted as three-dimensional block diagrams, the peak heights representing the frequency of observation. Predation risk and vegetation distribution influenced the location of foraging areas; kinship was an important factor in the determination of the amount of foraging area shared between individual marmots. Spatial overlap tended to be greater among close kin, but this was modified by individual behavioral characteristics, reproductive state, the existence of separate burrow systems within a colony, and the age of the animal. Mothers and juveniles, and littermates as young and resident yearlings, had nearly identical foraging areas.

Social variety in the yellow-bellied marmot: A population-behavioural system

Rates of amicable and agonistic behaviour are not correlated either within or between two colonies of Marmota flaviventris nor is there any consistent pattern of rates being higher in one colony than in the other. Rates of social behaviour are related to population density, the age-sex structure of the population, the individual behavioural characteristics of the residents and potential recruits, the way in which space is shared, and the number of years residents have lived together.

INDIVIDUAL DIFFERENCES IN COMPENSATORY REBOUND OF REM SLEEP, WITH PARTICULAR REFERENCE TO THEIR RELATIONSHIP TO PERSONALITY AND BEHAVIORAL CHARACTERISTICS

In subjecting 14 healthy university students to partial differential rapid eye movement (REM) sleep deprivation (PDRD), the compensatory rebound of REM sleep during the next night was determined, and showed fairly substantial individual differences in the increased percentage of REM sleep time. This rate was approximately the same for the same individual for two sleep recordings. These individual differences had no positive correlation with the decreased rate of REM time in the PDRD nights or with the percentage of REM time in the baseline night. Therefore, the individual differences in the increased percentage of REM time can be presumed to reflect individual differences in need for deprived REM sleep. Next, we looked into the relationship between the individual subject's personality and behavior characteristics, and his increased percentage of REM time. This revealed that the individuals who were extrovertive, active, optimistic, showy, and who had many friends had significantly higher increases in the percentage of REM time than the individuals who were introvertive, neurotic, inactive, nervous, modest, and who had few friends. Also discussed was the neurophysiological and biochemical basis of the central nervous system as the background for the relationship between the personality and behavioral characteristics and the increased percentage of REM sleep time.