Delay of gratification in a food exchange task in Goffin cockatoos (

1 Vermerk Inhalte dieser Masterarbeit wurden am 13. März 2013 im Fachjournal " Biology Letters " unter dem Namen " Goffin cockatoos wait for qualitative and quantitative gains but prefer´better´ tómore´ " Isabelle B. Laumer hat die Datenaufnahme der Studie durchgeführt und war maßgeblich bei der Erstellung der schriftlichen Form der Veröffentlichung beteiligt. Teile dieser Publikation wurden in der Masterarbeit verwendet. Delay of gratification in a food exchange task in Goffin cockatoos (Cacatua goffini) 1. Abstract Evidence for flexible impulse control over food consumption such as temporal discounting is rare outside humans. So far, only a few primate species as well as two corvids have been shown to be able to fully inhibit the consumption of a desirable food item in anticipation for a gain in quality or quantity for more than a minute. Goffin cockatoos (Cacatua goffini), a species which previously showed high levels of persistence and patience in other cognitive tasks, were tested in a delay of gratification task in which an initial food item could be exchanged against another reward after an increasing time delay. Subjects were able to bridge delays of up to 80s for a preferred food quality and up to 20s for a higher quantity. The decision to wait was influenced, by both, the difference in the quality of the two rewards and the duration of the delay. They tended to trade the initial item more often for the most preferred reward than for a less desirable one and hardly exchanged in controls in which the initial item was of higher value than the expected one. Additionally subjects tended to give up waiting earlier for a small than for bigger gain in value and seemed to assess if a reward is worth waiting for. Furthermore they showed idiosyncratic behavioural patterns when coping with longer delays, which could serve as distraction from consuming the initial food item. Taken together this provides the first evidence for temporal discounting in a psittacine species and hence in an avian species that does not cache food. The ability to inhibit an impulse to accept an instant option in anticipation for a delayed, more valuable one, is frequently considered a hallmark aspect of self-control and has long been believed to be a uniquely human attribute (Rachlin et al., 1991; Mischel et al., 1989). In humans, being patient is an advantageous skill in various aspects (Bramlett et al., 2012). Adult humans …