&quot;Sharing doesn&#039;t just enhance the welfare of humans,&quot; says Michael Gurven. &quot;The human subsistence niche would never have been possible without sharing. It&#039;s no coincidence that sharing is most pervasive and structured among humans, the one primate whose economy is defined by high levels of interdependence.&quot; (Credit: &quot;reaching for food&quot; via Shutterstock)