Farine Damien R, Spencer Karen A, Boogert Neeltje J
Edward Grey Institute of Field Ornithology, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; Department of Anthropology, University of California, Davis, Davis, CA 95616, USA; Smithsonian Tropical Research Institute, Panamá 0843-03092, Panama.
School of Psychology and Neuroscience, University of St. Andrews, St. Andrews KY16 9JP, UK.
Curr Biol. 2015 Aug 17;25(16):2184-8. doi: 10.1016/j.cub.2015.06.071. Epub 2015 Jul 23.
Stress during early life can cause disease and cognitive impairment in humans and non-humans alike. However, stress and other environmental factors can also program developmental pathways. We investigate whether differential exposure to developmental stress can drive divergent social learning strategies between siblings. In many species, juveniles acquire essential foraging skills by copying others: they can copy peers (horizontal social learning), learn from their parents (vertical social learning), or learn from other adults (oblique social learning). However, whether juveniles' learning strategies are condition dependent largely remains a mystery. We found that juvenile zebra finches living in flocks socially learned novel foraging skills exclusively from adults. By experimentally manipulating developmental stress, we further show that social learning targets are phenotypically plastic. While control juveniles learned foraging skills from their parents, their siblings, exposed as nestlings to experimentally elevated stress hormone levels, learned exclusively from unrelated adults. Thus, early-life conditions triggered individuals to switch strategies from vertical to oblique social learning. This switch could arise from stress-induced differences in developmental rate, cognitive and physical state, or the use of stress as an environmental cue. Acquisition of alternative social learning strategies may impact juveniles' fit to their environment and ultimately change their developmental trajectories.
早年生活中的压力会在人类和非人类身上引发疾病和认知障碍。然而，压力和其他环境因素也会影响发育路径。我们研究了不同程度的发育压力暴露是否会导致兄弟姐妹之间产生不同的社会学习策略。在许多物种中，幼崽通过模仿他人来获得基本的觅食技能：它们可以模仿同伴（横向社会学习）、向父母学习（纵向社会学习）或向其他成年个体学习（斜向社会学习）。然而，幼崽的学习策略是否取决于环境条件在很大程度上仍是个谜。我们发现，群居的斑胸草雀幼鸟仅从成年个体那里社会学习新的觅食技能。通过实验性地操纵发育压力，我们进一步表明社会学习目标具有表型可塑性。对照组幼鸟从父母那里学习觅食技能，而作为雏鸟时暴露于实验性升高的应激激素水平下的它们的兄弟姐妹，则仅从不相关的成年个体那里学习。因此，早年生活条件促使个体将策略从纵向社会学习转变为斜向社会学习。这种转变可能源于压力诱导的发育速度、认知和身体状态差异，或者将压力用作环境线索。获得替代性社会学习策略可能会影响幼崽对环境的适应性，并最终改变它们的发育轨迹。
