Individual variation in aggressiveness: ontogenesis and evolutionary consequences

我的研究旨在解释为什么有些人比其他人更具攻击性。自然选择和性选择应该产生在权衡侵略的成本和收益方面近似最优的社会行为。每个人都应该通过“选择”不同的生活策略，在许多时间尺度和货币中权衡最终的或进化的成本和收益。例如，一个更具攻击性的雄性可能会更成功地获得繁殖领地，但要付出更高的生理成本，对雌性的吸引力也会降低，或者在养育子女方面的效率也会低于一个不那么具有攻击性的雄性。了解哪些性状受近似机制的约束，哪些性状在生理上有联系，以及协变对于理解进化如何塑造这种复杂性状至关重要。我将调查在正常范围内早期激素暴露的变化对长期行为和内分泌变化的影响。手指比（2D:4D，食指与无名指长度之比）是一种广泛使用的人类产前睾酮暴露的替代指标；男性的2D:4D比例往往低于女性。人类的许多心理和生理特征显示出与手指比例有关的性内共变，包括攻击性。我将研究手指比例如何与人类产前雄激素暴露的其他假定指标相关，以及如何与小鼠大脑和行为的变化相关。我希望找出其他因素，有助于数字比例的变化，并进一步探索神经和行为相关的数字比例变化。我还将通过调查环境性别决定如何影响慈鲷的大脑和行为来检验同样的理论。除了影响性别之外，这种环境变化应该对两性二态行为的神经基础产生影响，就像子宫内邻近的雄性影响小鼠的大脑和行为一样。我将继续研究广泛形式的游戏作为攻击行为进化的模型。

My research aims to explain why some individuals are more aggressive than others.  Natural and sexual selection ought to produce social behaviours which are approximately optimal in trading off the costs and benefits of aggression.  Each individual ought to be trading-off ultimate, or evolutionary, costs and benefits across a number of time scales and currencies by "choosing" different life strategies.  For example, a more aggressive male may be more successful in gaining a breeding territory, but pay higher physiological costs and be less attractive to females, or be less effective at parenting, than a less aggressive male.  Understanding which traits are constrained by proximate mechanisms, which traits are physiologically linked, and covary is essential to understanding how evolution shapes this complex trait.    I will investigate the effect of variation in early hormone exposure, within normal ranges, on long-term behavioural and endocrinological variation.  Digit ratio (2D:4D, the ratio of index to ring finger length) is a widely used proxy measure for prenatal testosterone exposure in humans; men tend to have lower 2D:4D ratios than do women.  Many psychological, and physiological traits show intrasexual covariation with digit ratio in humans, including aggression.  I will investigate how digit ratio correlates with other putative indicators of prenatal androgen exposure in humans, and with variation in brain and behaviour in mice.  I expect to identify other factors that contribute to digit ratio variation, and explore further the neural and behavioural correlates of digit ratio variation.    I will also test the same theories by investigating how environmental sex determination influences brain and behaviour in cichlid fish.  Beyond influencing sex, such environmental variation ought to exert influence on the neural basis of sexually dimorphic behaviours in the same way that neighbouring males in utero influence mouse brain and behaviour.    I will continue to investigate extensive form games as a model of the evolution of aggressive behaviour.