Cells might "learn" without a brain

Single cells exhibit learning capacity through repeated stimuli, study finds

Cells, such as those making up human bodies, might be capable of 'learning', once deemed exclusive to complex creatures with brains, including birds and mammals, a new study has suggested.

Habituation is a simple form of learning in which one's response to a certain trigger lessens with repeated exposure. It is how one learns to ignore things happening often, such as the ticking of a clock. Habituation can also help people confront their fears.