Long-Term Attachments and Complex Cognition in Birds and Humans are Linked to Pre-Reproductive Prosociality and Cooperation. Constructing a Hypothesis

Human prosociality has often been regarded as an important step towards the capacity for empathy; i.e. to think of others in compassionate and caring ways. This ability, in turn, is related to social attachment. Many writers have rightly argued that, in order to understand the biology and evolution of social attachment, a comparative approach across many taxa is needed. Prosociality has been studied extensively in humans, non-human primates and some other mammals. Studies examining developmental stages and prosociality in altricial social birds are relatively sparse, of rather recent date and an altogether understudied area in avian behaviour and biology. The point of this paper is to report the discovery of a developmental social phase (and its cognitive and affective dimensions) in some long-lived avian species that is more than reminiscent of the development of prosocial behaviour in humans Based on this discovery; the paper develops a tentative hypothesis of pre-reproductive bonding/prosociality that can become the lynch-pin in mate-choice. Mate choice in birds, usually associated with physical features, is shown to be also based on individual personality and on social alliances that turn into social bonds well before the birds concerned reach sexual maturity. Such pre-sexual pair-bonding would be a particularly good adaption in preparation for long-term bonds and long periods of parenting, and it would contribute substantially to cooperative behaviour and, ultimately, to longevity. Similar to humans, birds are a vertebrate group whose strategies are based on long-term cooperative models and social attachments of parenting partners. In summary, it is suggested that mate-choice in long-lived, monogamous and largely monomorphic species may be foregrounded by a pre-sexual attachment to a potential mate. This mate-choice is thus not based on plumage or other external attributes. The questions of compatibility, personality and familiarity are discussed in detail as mechanisms that permit the expression of affiliations and attachments.