A new study published in Science has come to the shocking conclusion that crows are capable of conscious thought. The ground-breaking research could shift our notions of where and how consciousness occurs, and change the way we see the jet black birds roaming around campus.

This isn’t the first time that birds have proved surprisingly intelligent – from ravens with a ‘cognitive performance… on par with adult great apes,’ to bluetits teaching one another how to pierce the foil tops of milk bottles to get at the fatty liquid inside. Consciousness, however, holds a special place in our hearts. It is a property that we often like to consider exclusively human. Seeing this notion being challenged is both fascinating and humbling.

Here’s how the study worked: Researchers showed the crows a light source and trained them to indicate whether they had or had not seen the light. The birds found this task very easy when the light shone brightly, but when the light was dimmed measurements were made of neural activity in the birds’ brains which led to some curious conclusions. Neural activity did not only show whether the light had been sensed by the eye, but also seemed to show subjective awareness and thought. 

What the researchers found was that patterns of thought in the crows’ brains were similar when they thought that they had seen the light, regardless of whether or not the light had actually turned on. This indicated a level of conscious awareness beyond the brain activity associated with simply sensing the light source. ‘Nerve cells that represent visual input without subjective components are expected to respond in the same way to a visual stimulus of constant intensity,’ says Andreas Nieder, one of the authors of the study. ‘Our results, however, conclusively show that nerve cells at higher processing levels of the crow’s brain are influenced by subjective experience, or more precisely produce subjective experiences.’ 

This is all the more interesting considering how different the brain structure of the crow is from our own – ours being ‘layered’ while theirs is ‘smooth.’ These findings suggest that consciousness can occur in these “smooth” brain types as well as our own, which raises the possibility that other bird species are conscious too. 

Crows might have evolved this ability of conscious thought independently of us primates, or instead, the ability might have been inherited, by both crows and humans, from a common ancestor living 320 million years ago. This would suggest that consciousness is much more common than previously thought. 

Determining how common consciousness really is will take further exploration, as will answering another tantalizing question: Crows are capable of primary consciousness – they have subjective thoughts, but are they capable of secondary consciousness? Are the crows, like us, aware of these subjective thoughts?

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