Individual Differences In Behavioral Responses Research Articles

Individual differences in behavioural responses of pigs exposed to non-social and social challenges

The existence of individual differences in behaviour is a rarely considered but almost universal phenomenon. Individual differences in behaviour may reflect the existence of stable temperamental characteristics which could be used to improve understanding of behavioural mechanisms and to predict individuals' responses at different ages and in different contexts. In farm animals, the study of temperament has been largely restricted to dairy animals and to a limited range of contexts. This study examined the consistency of individual differences in responsiveness to a number of non-social and social challenges in female pigs. Two separate groups of gilts were exposed to a series of handling tests including willingness to leave the group residential pen, ease of movement through a corridor, response to a sudden human approach, resistance to restraint and vocalisation response to restraint. With the exception of vocalisation during restraint, individual scores for these tests tended to correlate and the scores for the correlated tests were therefore summed and 8 low scoring and 8 high scoring gilts selected from each group. The responses of these low and high responders to a novel object and to a group feeding test were then measured. In the novel object test, high responding gilts expressed overall a greater attention to the novel object. In the group feeding test there was no difference between low and high responders in the number of attacks won or lost but high responders won a significantly greater proportion of encounters. It was possible therefore to identify in female pigs, individuals that responded consistently to a variety of non-social challenges. In a social challenge test, however, not all elements of response were consistent with previously measured responses to non-social challenge. The variation between responses to social and non-social challenge in the present study suggests more than one underlying behavioural dimension controlling responses to challenge in female pigs.

Parental history of essential hypertension, active coping, and cardiovascular reactivity.

ABSTRACTDifferences in cardiovascular reactivity to stress between individuals with and without a family history of essential hypertension (EH) may be affected by stimulus characteristics and/or individual differences in behavioral response. Twenty‐four male students with a parental history of EH and 24 without a parental history of EH participated in two laboratory sessions during which two “active’ (mental arithmetic and the Stroop word‐color interference test) stressors and one “non‐active’ (isometric hand‐grip) stressor were presented. Family history subjects exhibited greater systolic blood pressure responses than non‐family history subjects only to the two active stressors in Session 2, despite the fact that, overall, isometric hand‐grip elicited the largest responses. High‐performing Stroop subjects with a parental history of EH displayed greater heart rate responses to the task than high‐performing subjects without a parental history of EH in both sessions. No group differences appeared among poor performers. The degree to which a stressor encourages active coping behavior appears to be one determinant of differences in cardiovascular response between individuals with and without a family history of EH.

Assessing the alcoholic's disposition to drink.

Reliable and valid techniques for assessing the alcoholic's disposition to drink would allow researchers to address many issues of clinical significance. This paper reviews some basic issues in behavioral assessment techniques, proposes several criteria for a reasonably general technique for assessing disposition to drink, and presents evidence relevant to the validity of one behavioral measure of disposition to drink. A study is presented which focuses on distinguishing good from poor treatment outcome subjects on the basis of their response patterns for alcohol during a simulated drinking binge. Alcoholic subjects were assigned to one of two treatment outcome groups based on treatment success evaluated at follow-up two months after hospital discharge. An analysis of the alcoholic's response patterns for alcohol during a simulated drinking binge revealed that good outcome subjects showed decreases in disposition to drink as their blood alcohol levels (BAL) rose, while poor outcome subjects showed increases in disposition to drink as their BAL increased. These results indicate that individual differences in behavioral response to alcoholization and withdrawal can index the alcoholic's potential for readdiction and relapse subsequent to hospital treatment and illustrate the role which behavioral assessment techniques can play in developing and refining models of human alcohol abuse.