Psychologist Harry Harlow did a series of studies with baby monkeys to demonstrate the theory of attachment, or dependence, of the young on a parent figure. In these studies the young were seperated from their parents and put into a lab. When given the choice of a monkey shaped wicker figure or a soft, blanket covered figure (both with bottles of formula) the infant monkeys routinely picked the softer of the two.

This may or may not be where Wickernipple gets their name.

This information is available in any beginning Psychology text and the APA website-