Department of Biological and Experimental Psychology, Queen Mary University of London, London E1 4NS, UK.
Department of Psychological Sciences, Birkbeck, University of London, London WC1E 7HX, UK.
Biol Lett. 2023 Feb;19(2):20220502. doi: 10.1098/rsbl.2022.0502. Epub 2023 Feb 8.
At the beginning of life, inexperienced animals use evolutionary-given preferences (predispositions) to decide what stimuli to attend and approach. Stimuli that contain cues of animacy, such as face-like stimuli, biological motion and changes in speed, are particularly attractive across vertebrate taxa. A strong cue of animacy is upward movement against terrestrial gravity, because only animate objects consistently move upward. To test whether upward movement is spontaneously considered attractive already at birth, we tested the early preferences of dark-hatched chicks () for upward- versus downward-moving visual stimuli. We found that, without any previous visual experience, chicks consistently exhibited a preference to approach stimuli that move upward, against gravity. A control experiment showed that these preferences are not driven by avoidance of downward stimuli. These results show that newborn animals have a gravity prior that attracts them toward upward movement. Movement against gravity can be used as a cue of animacy to orient early approach responses in the absence of previous visual experience.
在生命之初，缺乏经验的动物会利用进化赋予的偏好（倾向）来决定关注和接近哪些刺激。包含生物性线索的刺激，如类脸刺激、生物运动和速度变化，在脊椎动物中特别有吸引力。一个强烈的生物性线索是向上运动，逆着地球引力，因为只有有生命的物体才会持续向上运动。为了测试向上运动是否在出生时就被自发认为是有吸引力的，我们测试了暗纹小鸡（）对向上和向下运动的视觉刺激的早期偏好。我们发现，在没有任何先前视觉经验的情况下，小鸡一致地表现出对向上运动的刺激的偏好，即逆着重力运动。一个对照实验表明，这些偏好不是由对向下运动的回避驱动的。这些结果表明，新生动物有一种引力优先的机制，使它们趋向于向上运动。在没有先前视觉经验的情况下，逆着重力的运动可以作为生物性的线索，引导早期的接近反应。
