Awareness is a private affair. For instance, I can’t say for sure whether the other customers in the coffee shop where I’m sitting are conscious in the same way that I am. Perhaps instead they are zombies, doing a good impression of acting like self-aware human beings.
By talking to each other, we can quickly disregard this possibility. When it comes to animals, however, the jury is out. Is a chimpanzee self-aware? How about a cow? An insect?
This is not idle speculation. These questions matter. Our moral intuitions are based on the assumption that the person we are interacting with is consciously aware. And our legal system is imbued with the notion that consciousness matters. If we were to find that another animal species had a consciousness very similar to that of humans, then it may be remiss of us not to extend the same rights and protections to that species.
Recently, a prominent group of neuroscientists signed a declaration stating that several non-human animal species are conscious. They reasoned that many mammals share brain structures – the thalamus, neocortex – that are involved in consciousness in humans, and display similar behavioral repertoires, such as attentiveness, sleep and capacity for decision-making. Therefore it is more likely than not that they have a similar consciousness.
While this seems intuitive, we need to stop and examine their reasoning. It all comes down to the kind of consciousness we are talking about. No one doubts, for example, that animals have periods of both sleep and wakefulness. What is at issue is whether they are aware in the same way that you and I are aware when we are awake.
Imagine you are in the cinema, engrossed in the latest blockbuster. There’s a good chance (especially if the film is any good) that while you are experiencing the film, you are not aware that you are experiencing the film. “Meta”-awareness is absent. Now imagine that you are condemned to spend the rest of your life without meta-awareness, continuously engrossed in the film of your own life. I’d wager it wouldn’t be much of an existence; as Socrates suggested, the unexamined life is not worth living.
Whether or not animals have this capacity for meta-awareness is unclear. Without the ability to report mental states, it is notoriously difficult to assess. But one particularly promising test involves judgments of control, or “agency”. Consider playing an arcade game after the money has run out – at some point, you realize that rather than steering your digital car through the streets of Monte Carlo, your efforts at the wheel are having no effect whatsoever. This realization – that you are no longer in control - is known as a judgment of agency, and may be intimately linked to meta-awareness.
In a recent study conducted in Kyoto, Japan, researchers asked whether chimpanzees could make judgments of agency. The task was to move a computer cursor to bump into another target displayed on the screen. The twist was that another decoy cursor was also present on the screen, whose movements were replayed from a previous trial. Thus the chimpanzee had control of one of the cursors, but not the other, even though visually they were identical. After the trial ended, the animals were trained to indicate the cursor that they had been controlling. All three chimpanzees correctly indicated this “self” cursor around 75% of the time. As the experimenters note, “Because both the self- and distractor cursor movements were produced by the same individual, the movements were presumably indistinguishable to a third person (and to the experimenters), who passively observed the display.” In other words, the only way to do the task is to monitor internal states, which is a pre-requisite for meta-awareness.
Judgments about another species’ consciousness should not be taken lightly. In particular, we should be careful about what kind of consciousness we are talking about. The kind that matters most from a moral and legal perspective is the capacity to be aware of internal states and intentions. Initial evidence suggests that some animals, particularly the great apes, may have this higher-order reflective capacity. This should give us greater pause for thought than the presence of primary or phenomenal consciousness in lower animals.