ASME's Top 40 Best Magazine Covers of the Last 40 Years:

October 1978

This cover of National Geographic magazine is entitled Conversations with a Gorilla, with Koko the gorilla snapping a photograph of her reflection in the mirror. The photo was of such high quality and significance that it was chosen to be the cover photo for the October 1978 National Geographic article featuring Koko. Developmental psychologist Francine Patterson spent six years with Koko teaching her sign language and this led Patterson and other researchers to believe Koko displayed evidence of linguistic capabilities.