Reuters / Carlos Jasso
This is a palm cockatoo (Probosciger aterrimus) photographed inside a cage at the "El Nido" (The Nest) aviary park in Ixtapaluca, on the outskirts of Mexico City, on July 7, 2011.
By Alister Doyle, Reuters
OSLO -- Cockatoos can delay eating nuts in order to win tastier ones, a surprise sign that birds can exercise self-control, a trait usually seen as the preserve of animals with larger brains, a study showed on Wednesday.
Scientists gave Goffin cockatoos, a mainly white species from Indonesia, a nut while showing them a more attractive one just out of reach. If the birds did not nibble the first nut for up to 80 seconds, they learned they would get the second instead.
"Imagine placing a cookie directly into a toddler's mouth and telling him/her that he/she will only receive a piece of chocolate if the cookie is not nibbled for over a minute," said lead author Alice Auersperg at the University of Vienna.
"Only few, typically large-brained animals have been shown to be able to inhibit the consumption of an immediate food reward in anticipation of a bigger one for more than one minute," the university said in a statement.
The birds were given pecan nuts, and all 14 of those studied waited for up to 80 seconds to win a more attractive cashew nut, according to the findings in the journal Biology Letters.
A video showed one bird, Muppet, waiting 40 seconds while strutting agitatedly around a table top with the first nut in its beak before exchanging it for a second.
Self-control in human infants was studied in the 1970s in the Stanford Marshmallow Experiment. Under that test, children were given a marshmallow and told that they would get a second if they did not eat the first for several minutes.
Commenting on that test, the Vienna University statement said. "Interestingly, children who were able to wait for the delayed reward showed greater success in adult life than the ones who ate the first marshmallow right away."
The ability to trade depends on being able to suppress the impulse to eat the first reward. It also requires a judgment on the reliability of the trader and the relative costs of the delayed reward, Vienna University said.