In certain species, especially bonobos and humans, non-procreative sexual play has come to serve important social functions. Adaptive as far as reproduction is concerned - which is why sexual desire evolved in the first place - sex is "exaptive" with respect to its ability to create and maintain social bonds. In other essays, Gould saw the brain as serving an extraordinary number of exaptive roles in civilized societies, in addition to its continuing adaptive functions.
某些物种，特别是小黑猩猩和人类，他们非繁殖性的性行为承担了重要的社会功能。只要是与繁殖有关的适应性——这也是性欲进化的首要原因，性在创造和保持社会关系上具有“扩展适应性”（exaptive）。古尔德在文章中，认为在文明社会中，大脑在其持续适应的功能外，还在扩展适应上承担了非常多的功能。One of the most interesting exaptations characteristic of human behavior and culture is the very fact that humans take an interest in modulating their brain-body states. Many animals do this to a certain degree. Horses who get bored or lonely while isolated in a paddock sometimes take pleasure in startling themselves. A lively snort causes a chemical feedback that induces a startle reflex and an exciting wash of neurochemicals. Birds who flock around trees bearing fruit that is somewhat past its prime and eat the alcohol-laden fruit have found a way to ingest, rather than manufacture, mood-altering substance.