Why is social behaviour in animals adversely affected by barren housing conditions?

贫瘠的环境，比如小而贫瘠的笼子，会对动物之间的互动产生不利影响。生产力所需的相互作用（如交配、孕产妇保健）可能受到损害；反映或带来良好福利的互动（如游戏）经常减少；攻击性往往会增加。这对许多物种来说都成立，但以实验室老鼠为例，在繁殖和抚养幼崽方面，饲养丰富的老鼠比饲养贫瘠的老鼠更好，而且（尤其是雌性老鼠）它们与笼子里的同伴打架的次数更少。因此，我将调查在贫瘠环境中长大的行为，认知和情感影响如何阻碍社会行为。我的假设是：1)行为的不灵活性（倾向于形成固定的惯例，“坚持”，并执行重复的，可预测的刻板行为）损害了正常社交，性和母性行为至关重要的灵活性；2)焦虑和抑郁样的变化（快感缺乏和负面判断偏差）减少了积极社会互动的动机，并导致将中性社会线索解释为威胁的倾向。

Impoverished environments, such as small barren cages, can adversely affect animals' interactions with each other. Interactions needed for productivity (e.g. mating, maternal care) can be impaired; interactions that reflect or cause good welfare (e.g. play) often decline; and aggression often increases. This holds for many species, but in laboratory mice, for instance, enriched-housed mice are better than barren-housed mice at producing and raising viable pups, and (especially if female) they fight less with cagemates. I will therefore investigate how the behavioural, cognitive & affective effects of being raised in barren environments impede social behaviour. My hypotheses are that 1) behavioural inflexibility (tendencies to form fixed routines, 'perseverate', and perform repetitive, predictable stereotypic behaviour) compromises the flexibility crucial for normal social, sexual & maternal behaviour; and 2) anxiety- and depression-like changes (anhedonia and negative judgment biases) reduce motivations for positive social interactions and cause predispositions to interpret neutral social cues as threatening. Mice (C57Bl/6, DBA/2 & BALB/c) will be used as ideal models: enrichment affects their social behaviour, their stereotypies often covary with perseveration, and females exhibit social learning, mate choice, nest-mate choice, & social buffering (where the presence of a conspecific reduces stress). Further, about 30 million are used in research each year, making improving their welfare highly impactful. My 26 HQP will test the predictions that a) enriched-raised females are less aggressive to cagemates & intruders; better at demonstrating information in social learning tasks; preferred over barren-raised females as cage-mates; and better ‘stress buffers’ than barren-raised females; b) enriched-raised males are more attractive to females, and also induce better maternal care in those that they mate, than barren-housed males; and c) enriched females are better mothers (e.g. faster & more responsive in pup retrieval tests), and that pregnant/lactating females prefer enriched females to barren-raised females as communal nesting partners. As potential mediators of all effects found, we will test the hypotheses that i) enriched mice are less perseverative (helping them make appropriate adjustments to changing social signals), and that ii) enriched mice find social contact more rewarding and less threatening than do barren-reared mice. How impoverished environments compromise social interactions has never before been systematically investigated, and the hypotheses under test are novel. This work has broad application, not just for laboratory mouse breeders & colony managers, but beyond to farm, zoo & other laboratory animals, via identifying environmental improvements as potential ways to boost both productivity and welfare by reducing social problems.