«One possibility is that these animals need particular cues from environmental bacteria that are not being provided in the lab,» she said. (sciencedaily.com)
Byrne says the fact that elephants seem to pick out particular cues from their environment that mark Maasai warriors suggests that the animals can actually classify whole subsets of a species based on the threat they pose. (scientificamerican.com)
Over the course of the game, external stimuli (as mentioned by Eboracum: big hits, powerful blocks, other demonstrations) can attract the attention to and focus on some particular cue. (sbnation.com)