What is the source of this story about tribe seeing a western video?

I've heard about an occasion where a few westerners visited an isolated tribe (might have been in Africa) and showed them video for the first time. The video had clips about all different sides of life (depicting culture, cities etc). The tribesmen looked it with utter indifference and when afterwards asked, what they saw, the one answer they got from all tribesmen was "chicken". The westerners looked through the clip several times and finally saw that in one frame there was a small chicken in the corner of the screen or something. The point of the story being, that we only recognise the familiar. I've done a few searches but have not found any information about this story. I'd like to find some sources or background information about it. Does anyone recognise it?