Biological psychology
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Biological psychology · May 2010
Randomized Controlled TrialMotivational and situational factors and the relationship between testosterone dynamics and human aggression during competition.
Men engage in aggression at a cost to extrinsic reward, and this behaviour is associated with a rise in testosterone. To characterize the factors underlying aggression, men were assigned to one of the four experimental conditions of a computer game in which they were provoked (points were stolen from them or not) and/or received reward for aggression (received points for aggression or not). ⋯ Moreover, individual differences in aggressive behaviour among these men were positively correlated with the extent to which they enjoyed the task and with testosterone fluctuations. These results indicate that costly aggressive behaviour is intrinsically rewarding, perhaps to regulate future interactions, and that testosterone may be a physiological marker of such reward value.
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Biological psychology · May 2010
Aging diurnal rhythms and chronic stress: Distinct alteration of diurnal rhythmicity of salivary alpha-amylase and cortisol.
The present study assessed diurnal profiles of salivary alpha-amylase (sAA), proposed as a marker of autonomic activity, and salivary cortisol in competitive ballroom dancers as well as age- and sex-matched controls to investigate age-related changes of basal activity and potential chronic psychosocial stress-related alterations. According to the Allostatic Load (AL) hypothesis of a cumulative wear and tear of the body we expected to see physiological accumulation of the effects of stress and age especially pronounced in older dancers. Dancers and controls collected five saliva samples throughout the day. ⋯ In conclusion, higher overall output of sAA in older adults is in line with the phenomenon of a sympathetic "drive" with increasing age. Furthermore, a lower output of sAA in people who are more physical active is in line with the hypothesis of an exercise-induced decrease of sympathetic activity. Overall, our study does not support the AL hypothesis, but rather highlights the importance of regular physical activity and social environment in promoting health.