PLoS One. 2014 Jul 23;9(7):e103049. doi: 10.1371/journal.pone.0103049. eCollection 2014.
Abstract
While humans are able to understand much about causality, it is unclear to what extent non-human animals can do the same. The Aesop's Fable
paradigm requires an animal to drop stones into a water-filled tube to
bring a floating food reward within reach. Rook, Eurasian jay, and New
Caledonian crow performances are similar to those of children under
seven years of age when solving this task. However, we know very little
about the cognition underpinning these birds' performances. Here, we
address several limitations of previous Aesop's Fable
studies to gain insight into the causal cognition of New Caledonian
crows. Our results provide the first evidence that any non-human animal
can solve the U-tube task and can discriminate between water-filled
tubes of different volumes. However, our results do not provide support
for the hypothesis that these crows can infer the presence of a hidden
causal mechanism. They also call into question previous
object-discrimination performances. The methodologies outlined here
should allow for more powerful comparisons between humans and other
animal species and thus help us to determine which aspects of causal
cognition are distinct to humans.
