Karen Pryor claims: "Research in neurophysiology has identified the kinds of stimuli—bright lights, sudden sharp sounds—that reach the amygdala first, before reaching the cortex or thinking part of the brain. The click is that kind of stimulus.

I hypothesize that the clicker is a conditioned "joy" stimulus that is acquired and recognized through those same primitive pathways, which would help explain why it is so very different from, say, a human word, in its effect."