A biologist and philosopher are suggesting that insects have subjective experiences of the world.
Kemal Atlay

19 Apr 2016 - 12:14 PM  UPDATED 19 Apr 2016 - 12:14 PM

You might think that a bee is nothing more than a tiny robot with no opinion about the weather or the taste of nectar, but according to a new theory, insects might have consciousness – and are able to have subjective experiences just like humans and other animals do.

In a review article just published in PNAS, researchers from Macquarie University have proposed that consciousness is an evolutionary trait controlled by specific regions of the brain in both vertebrates and invertebrates.

“What we wanted to do was to frame the question of consciousness as a neurobiological hypothesis, so our starting point was that we believe consciousness is an evolved trait,” Associate Professor Andrew Barron, a neurobiologist and co-author of the paper, told SBS Science.

Barron explains that there are two types of conscious states agreed upon by philosophers, psychologists and neurobiologists – ‘awareness’ and ‘self-awareness’. According to him, evidence suggests that insects can have subjective experience simply as a result of being aware of their world.

“The human conscious experience is all tied up in self-awareness, it’s all about what things mean to me, whereas awareness is simply being aware of anything, but not having that reflective capacity or component to it,” says Barron.

Thus a subjective experience for something like a bee could simply mean being aware of its environment in a unique way.

Looking into the midbrain

Recent studies suggest that awareness is localised to the human midbrain, an ancient neural structure that is highly conserved across all vertebrates, whereas self-awareness is localised to the neocortex, which surrounds the midbrain.

According to Barron, the insect brain has structures that are functionally, albeit not anatomically, similar to the vertebrate midbrain.

“We think the totality of the insect brain is doing functionally similar processing to the vertebrate midbrain,” says Barron, “so the insect brain is also generating a unified neural model where the insect is in space relative to the relevant things around it weighted by the memory and past experience of that insect.”

“If we can understand how a nervous system can generate basic awareness, we can then pose hypotheses about what we would need to add to that nervous system to generate higher levels of consciousness,” Barron says.

Co-author and philosopher Dr Colin Klein says that consciousness “arose because it helped solve very practical problems of action selection for moving animals in complicated environments”.

“When we say that insects are conscious or have subjective experience or are aware, we mean that it feels like [something], it means something to the insect to move around the world,” says Klein.

“What we don’t mean is that you have an insect sitting there, thinking to itself ‘Mmm I feel hungry now, reckon I ought to pop off down to another flower’.”

In the realm of philosophy

Professor Daniel Hutto, a philosopher from the University of Wollongong, is unconvinced by the hypothesis and thinks it needs to incorporate other theories, such as the Higher-Order Thought theory.

“The authors don’t properly address enough of the philosophical concerns around the notion of phenomenal consciousness to make the case for their hypothesis convincing,” Hutto told SBS Science.

However, he agrees that if animals other than humans can also experience consciousness, it could radically alter our interactions with other vertebrate and invertebrate species.

“To think that non-human animals might genuinely lack phenomenal consciousness is surely to remove a compelling reason for treating them with the care and concern that any genuinely feeling creatures deserve,” he says.

“It would be, therefore, quite morally significant if a successful case could be made that phenomenal consciousness can exist independently of higher order thoughts.”

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