Human–Grey parrot (Psittacus erithacus) reciprocity: a follow-up study
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In a previous study (Péron et al. in Anim Cogn, doi: 10.1007/s10071-012.05640, 2012), Grey parrots, working in dyads, took turns choosing one of four differently coloured cups with differing outcomes: empty (null, non-rewarding), selfish (keeping reward for oneself), share (sharing a divisible reward), or giving (donating reward to other). When the dyads involved three humans with different specific intentions (selfish, giving, or copying the bird’s behaviour), birds’ responses only tended towards consistency with human behaviour. Our dominant bird was willing to share a reward with a human who was willing to give up her reward, was selfish with the selfish human, and tended towards sharing with the copycat human; our subordinate bird tended slightly towards increased sharing with the generous human and selfishness with the selfish human, but did not clearly mirror the behaviour of the copycat. We theorized that the birds’ inability to understand the copycat condition fully—that they could potentially maximize reward by choosing to share—was a consequence of their viewing the copycat’s behaviour as erratic compared with the consistently selfish or giving humans and thus not realizing that they were indeed being mirrored. We suggested that copycat trials subsequently be performed as a separate experiment, without being contrasted with trials in which humans acted consistently, in order to determine if results might have differed. We have now performed that experiment, and shown that at least one Grey parrot—our dominant—responded in a manner suggesting that he deduced the appropriate contingencies.
KeywordsGrey parrot cognition Reciprocity Non-human sharing Psittacus erithacus
Thornburg was supported by the Harvard College Research Program. Pepperberg, Gross, and Gray were supported in part by donors to The Alex Foundation (particularly the Anders Sterner family, Marc Haas Foundation, Anita Keefe, Janice Boyd, Alex and Michael Shuman, Nancy Sondow, Nancy Chambers, the Howard Bayne Fund, Kathryn and Walter McAdams, Grey Parrot Studios, Katie Dolan, the Raleigh-Durham Caged Bird Society, Joseph Golden, Pat Hill, Elva and Bob Mathiesen, the Platinum Parrot, Jan and Jeff Strong, the Oklahoma Avicultural Society, Bill Broach, Nancy Clark, Deborah Rivel Goodale/Wildtones, The Robert D. Goodale Fund (via the Indian River Community Foundation), Patti DeMar Hauver, Roni Duke, Don and Grace Wheeler). We thank Maryam Vaziri Pashkam for advice with statistical analyses, Jonathan Richie for assistance with some trials, Harrison’s Bird Food and Fowl Play for foods and treats, Bird Paradise for Griffin’s cage, and Carol D’Arezzo for Griffin’s stand. The study procedures comply with the current laws of the USA, where they were performed.
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