Friday, August 17, 2007

Crows and Tools

The BBC News website has reported on another study involving the New Caledonian crows originating from a few small islands in the Pacific ocean (picture above from BBC news story). This species came to light with the famous experiments at Oxford University (by Kacelnik and associates) on Betty and Abel, which showed their ability not only to use tools, but also to fashion them from non-tool and non-naturally occurring materials. These abilities had previously only been observed in humans and some primates.

The present study looked at 'meta-tool use' by this species. Meta-tool use is the ability to use one tool on another to achieve the desired state/goal. Seven wild crows were used in the experiment, with the following setup: a crow was presented with a box in which there was food. It was also provided with a stick, which by itself was not long enough to get the food. Another box was also present, in which there was a longer stick. The solution to getting the food is then to use the short stick to get the long stick, and the long stick to get the food from the first box: meta-tool use. The results showed not only that the crows were able to to this, but that this performance was achieved in the first trial (in 6 out of 7 subjects) – see the paper abstract below. As suggested by the paper, this indicates that the crows abstracted from, or used in some other way, information that had been previously learned to a novel situation – an not merely through trial and error.

This being a domain traditionally the preserve of humans, if found to be verifiable/replicable (from my understanding, this is the only study conducted of its type), the results could have a wide variety of implications in a number of fields. As I understand it, the learning and abstraction capabilities of the higher primates are explained by the 'closeness' in brain structure between humans and these animals: that it is the human brain that is capable of these feats, and that primates have limited capabilities due to similarities. The brain of the bird, in this case New Caledonian crow, however I assume to bear very little similarity by comparison. In this case, it would not be the structure which is important (not necessarily anyway), but some other property. I'm hardly intimate with the details of the study (or indeed the neuroanatomy of these crows), but I view it as an interesting issue: I'm thinking here of Fuster's Network Memory theory, of which, while being a model of the human information processing system, the underlying principles I assume may be equally applied to any neurally-based nervous system, including that of the crow (the detailed accounts of the specific brain regions in the Network Memory theory, particularly the prefrontal cortex, would naturally not apply – but perhaps this functionality may be physically represented in some other, limited, way?). Of course, these last thoughts are pure speculation on my part – perhaps some of your comments could help me untangle my thoughts?...

A crucial stage in hominin evolution was the development of metatool use—the ability to use one tool on another [1] and [2]. Although the great apes can solve metatool tasks [3] and [4], monkeys have been less successful [5], [6] and [7]. Here we provide experimental evidence that New Caledonian crows can spontaneously solve a demanding metatool task in which a short tool is used to extract a longer tool that can then be used to obtain meat. Six out of the seven crows initially attempted to extract the long tool with the short tool. Four successfully obtained meat on the first trial. The experiments revealed that the crows did not solve the metatool task by trial-and-error learning during the task or through a previously learned rule. The sophisticated physical cognition shown appears to have been based on analogical reasoning. The ability to reason analogically may explain the exceptional tool-manufacturing skills of New Caledonian crows.

No comments: