The Measure of a Fly – Do insects share awareness with humans?

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Consciousness is an incredibly murky, hard-to-define and difficult-to-study phenomena. And to ask what was going on inside an animal’s head was thought unscientific and deemed an illegitimate question.

By the 1960s, things started to change, thanks in part to pioneers including Jane Goodall and her groundbreaking research on wild chimpanzees. Scientists started to suspect what anyone with a dog, cat or cockatoo intrinsically knew: these creatures have emotions and inner lives and aren’t (entirely) just some kind of instinct-programmed jack-in-the-box.

Today, animal consciousness is no longer a taboo topic among scientists, and what we’re learning is redefining what we thought we knew about our human-centric concept of being conscious. Apes can use sign language and recognize themselves in a mirror. Birds and octopuses exhibit flexible tool use.

Chimpanzees fashion weapons and murder for no apparent reason, which shouldn’t come as too much of a surprise since they’re our closest relative. Elephants might even grieve for their dead relatives, though we don’t think they understand death the way humans do. Some elephants actually enjoy painting and are reported to spontaneously paint pictures of other elephants. The examples are endless, and many are controversial, but it’s clear that animals do have minds of their own. But they’re not always driven by motivations to which humans can relate. It’s when we anthropomorphize them that research goes astray.
All consciousness is thought to be an emergent property, somehow generated by the vast neural circuitry in the brain and nervous system. We have clues as to places in the mammalian and avian brains where it might originate, and know that it involves some very complex feedback mechanisms. But what’s surprising is that the rudiments of this “consciousness circuitry” are being found in animals most people wouldn’t assume were aware of anything. Is a cockroach conscious, or a fly, or a honeybee? The data is coming in, and while the answer isn’t a resounding “yes,” it’s not quite “no” either.

Bruno van Swinderen, a researcher at the Neurosciences Institute (NSI) in San Diego, California, has found evidence that the tiny brains of insects are doing a lot more than we thought. What he and other researchers see, by attaching electrodes directly to neurons inside the brain, is that even insects are able to shift their attention from one object or situation to another. Even though insects only possess between 250,000 and 1 million neurons (humans have about 85 billion), they are wired in massive feedback circuits just like the brains of animals we already consider to be “conscious.” Van Swinderen isn’t claiming that flies are conscious in the same way mammals are, and even prefers using the word “salience” rather than “attention,” but the rudiments of consciousness may be there. “That, to me, is just a short hop, skip and a jump away from what might be consciousness. It could be exactly the same mechanism in a fly and a human,” says van Swinderen.

This is all very speculative, but when one considers that the structure of neurons is strikingly similar across the entire animal kingdom, the idea seems less farfetched. While wings, eyes and other adaptations evolved multiple times in different lineages (bird, insect and bat wings evolved independently), it’s possible that a primitive brain evolved only once, 600 million years ago in a creature called Urbilateria, the last common ancestor of all bilaterally symmetrical animals. Heinrich Reichert of the University of Basel has found some genetic evidence for this. “It reveals,” says Reichert, “a deep relatedness in the brains of flies and fish and mice and men that certainly was not expected by just looking at the superficial anatomy.”

No one even agrees on the exact definition of consciousness, so the scientific debate and ethical implications of this subject will be around for a long, long time. What’s really emerged since the 1960s is that scientists are starting to expand their human-centric view of consciousness and intelligence. Man is unique, but not quite so special as we thought. Animals, in their own way, have emotions, experiences, intentions and inner lives. In July 2012 this view has culminated in an official statement by a group of scientists at the “Consciousness in Human and Nonhuman Animals” conference in Cambridge. In part it reads, “Convergent evidence indicates that non-human animals have the neuroanatomical, neurochemical, and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors. Consequently, the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness. Non-human animals, including all mammals and birds, and many other creatures, including octopuses, also possess these neurological substrates.” No mention of cockroaches or honeybees (yet), but it’s a far cry from the views expressed 100 years ago. We’re not detracting from the wealth of scientific contributions made by the great psychologists of that era, but the above statement would probably have them rolling over in their graves.

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