We use the term “enrichment” a lot at the Gorilla Foundation. The term generally refers to anything that makes the gorillas” lives more enjoyable, meaningful, rewarding and/or natural (ie, similar in function or effect to what they might experience in a non-captive environment).
Koko and Ndume are given lots of opportunities for enrichment, including food that they have to forage for (placed both high and low in their outdoor enclosures), and items that simulate trees, plants and rocks and that promote climbing, hiding, nesting, playing games and communicating with everyone in their environment – including the humans responsible for their care and well being.
Thus, of course, sign language (ASL) is both a form of enrichment, and a tool that the gorillas can use to help us evaluate how well we”re doing at providing enrichment.
Take a look at the above photo featuring Koko, and see how many enrichment items you can find in her immediate surroundings.