Podcast with Alex Kacelnik on new caledonian crow and tool use

Can a crow that has never seen a particular problem still build the right tool to solve it, and what does that tell us about the nature of animal intelligence? Alex Kacelnik explores the boundaries between insight and learning in New Caledonian crows.

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Alex Kacelnik brings a biologist's perspective to animal cognition, positioning intelligence as an evolved toolkit shaped by natural selection rather than an abstract capacity to be ranked on a human-centric scale. He draws a critical distinction between risk, where probabilities are known, and uncertainty, where even the nature of the problem is unclear, arguing that learning transforms individual uncertainty into manageable risk by filling in the parameters that evolution could not anticipate.

The centerpiece of the discussion is the New Caledonian crow, the most intensely tool-dependent non-human species known. These birds manufacture at least five categories of tools including hooks, straight sticks, and elaborately shaped pandanus leaf strips, showing regional variation that suggests cultural transmission. In laboratory settings, the crows demonstrate remarkable flexibility: they select tools of appropriate length and diameter for specific problems, build hooks when straight tools will not work, and solve multi-step problems requiring sequential tool use on a trial-unique basis. Kacelnik emphasizes that these behaviors cannot be fully explained by chaining previously reinforced responses, as the complete sequences have never been experienced before.

Yet Kacelnik resists easy mentalistic interpretations. He positions himself closer to the "killjoy behaviorist" than the "mystical psychologist," insisting that terms like insight, planning, and understanding should only be used when backed by algorithmic models of how experience translates into novel solutions. A key experiment illustrates this principled caution: crows could innovate by dropping stones into a mechanism to release food, but only if they had prior experience with how the magnetic release mechanism worked. Innovation requires partial knowledge as scaffolding, not magical leaps of comprehension.

The episode also examines how crows use tools not just for food extraction but for exploring potentially dangerous objects at a safe distance, and how sexual selection in siskins illustrates the complex evolutionary pressures shaping cognitive abilities across bird species.