Affectionate bonds are formed as a result of interactions with the attachment figure, that is, between child and parent. Emotional life is seen as dependent on the formation, maintenance, disruption or renewal of attachment relationships.

Imprinting of various degrees of intensity is now known to occur in many birds, such as the zebra finch. The zebra finch raised with Bengalese finches preferred mating with the Bengalese finch. Even after forceful mating with the zebra finch, these birds would still go back and attempt to mate with the Bengalese finches. To which the Bengalese generally rejected them. This implies a critical period for sexual imprinting. The birds sought out mates, which looked like their parents. The longer the exposure to the Bengalese finch, the harder it became to get these zebra finches to mate with their own kind, in some cases impossible.

Filial imprinting is...