New research, reported in the open-access journal PloS ONE, has yielded a surprising result: an Indonesian species of parrot known as Goffin’s Cockatoo, Tanimbar Corella or Goffin’s Corella (Cacatua goffiniana), can solve complex mechanical problems that involve undoing a series of locks one after another.
“We cannot prove that the birds understand the physical structure of the problem as an adult human would, but we can infer from their behavior that they are sensitive to how objects act on each other, and that they can learn to progress towards a distant goal without being rewarded step by step,” said study co-author Prof Alex Kacelnik of Oxford University.
In the study, 10 untrained Goffin’s cockatoos faced a puzzle box showing a nut behind a transparent door secured by a series of five different interlocking devices, each one jamming the next along in the series. To retrieve the nut the birds had to first remove a pin, then a screw, then a bolt, then turn a wheel 90 degrees, and then shift a latch sideways.
One bird, called Pipin, cracked the problem unassisted in less than two hours, and several others did it after being helped either by being presented with the series of locks incrementally or being allowed to watch a skilled partner doing it.
The study authors were interested in the birds’ progress towards the solution, and on what they knew once they had solved the full task. The scientists found that the birds worked determinedly to overcome one obstacle after another even though they were only rewarded with the nut once they had solved all five devices. They suggest that the birds seemed to progress as if they employed a ‘cognitive ratchet’ process: once they discovered how to solve one lock they rarely had any difficulties with the same device again. This is consistent with the birds having a representation of the goal they were pursuing.
After the cockatoos mastered the entire sequence, the scientists investigated whether the birds had learnt how to repeat a sequence of actions or instead responded to the effect of each lock.
“After they had solved the initial problem, we confronted six subjects with so-called ‘transfer tasks’ in which some locks were re-ordered, removed, or made non-functional. Statistical analysis showed that they reacted to the changes with immediate sensitivity to the novel situation,” explained lead author Dr Alice Auersperg from Vienna University.
“The birds’ sudden and often errorless improvement and response to changes indicates pronounced behavioral plasticity and practical memory. We believe that they are aided by species characteristics such as intense curiosity, tactile exploration techniques and persistence: cockatoos explore surrounding objects with their bill, tongue and feet. A purely visual explorer may have never detected that they could move the locks,” said senior author Dr Auguste von Bayern of Oxford University.
Bibliographic information: Auersperg AMI et al. 2013. Explorative Learning and Functional Inferences on a Five-Step Means-Means-End Problem in Goffin’s Cockatoos (Cacatua goffini). PLoS ONE 8 (7): e68979; doi:10.1371/journal.pone.0068979