Emotions like fear are not something inherited from our unconscious animal past. Instead they arise from the higher-order aspects that make human thought conscious. That (if I’ve got it right) is the gist of an interesting paper by LeDoux and Brown.
A mainstream view of fear (the authors discuss fear in particular as a handy example of emotion, on the assumption that similar conclusions apply to other emotions) would make it a matter of the limbic system, notably the amygdala, which is known to be associated with the detection of threats. People whose amygdalas have been destroyed become excessively trusting, for example – although as always things are more complicated than they seem at first and the amygdalas are much more than just the organs of ‘fear and loathing’. LeDoux and Brown would make fear a cortical matter, generated only in the kind of reflective consciousness possessed by human beings.
One immediate objection might be that this seems to confine fear to human beings, whereas it seems pretty obvious that animals experience fear too. It depends, though, what we mean by ‘fear’. LeDoux and Brown would not deny that animals exhibit aversive behaviour, that they run away or emit terrified noises; what they are after is the actual feeling of fear. LeDoux and Brown situate their concept of fear in the context of philosophical discussion about phenomenal experience, which makes sense but threatens to open up a larger can of worms – nothing about phenomenal experience, including its bare existence, is altogether uncontroversial. Luckily I think that for the current purposes the deeper issues can be put to one side; whether or not fear is a matter of ineffable qualia we can probably agree that humanly conscious fear is a distinct thing. At the risk of begging the question a bit we might say that if you don’t know you’re afraid, you’re not feeling the kind of fear LeDoux and Brown want to talk about.
On a traditional view, again, fear might play a direct causal role in behaviour. We detect a threat, that causes the feeling of fear, and the feeling causes us to run away. For LeDoux and Brown, it doesn’t work like that. Instead, while the threat causes the running away, that process does not in itself generate the feeling of fear. Those sub-cortical processes, along with other signals, feed into a separate conscious process, and it’s that that generates the feeling.
Another immediate objection therefore might be that the authors have made fear an epiphenomenon; it doesn’t do anything. Some, of course, might embrace the idea that all conscious experience is epiphenomenal; a by-product whose influence on behaviour is illusory. Most people, though, would find it puzzling that the brain should go to the trouble of generating experiences that never affect behaviour and so contribute nothing to survival.
The answer here, I think, comes from the authors’ view of consciousness. They embrace a higher-order theory (HOT). HOTs (there are a number of variations) say that a mental state is conscious if there is another mental state in the same mind which is about it – a Higher Order Representation (HOR); or to put it another way, being conscious is being aware that you’re aware. If that is correct, then fear is a natural result of the application of conscious processes to certain situations, not a peculiar side-effect.
HOTs have been around for a long time: they would always get a mention in any round-up of the contenders for an explanation of consciousness, but somehow it seems to me they have never generated the little bursts of excitement and interest that other theories have enjoyed. LeDoux and Brown suggest that other theories of emotion and consciousness either are ‘first -order’ theories explicitly, or can be construed as such. They defend the HOT concept against one of the leading objections, which is that it seems to be possible to have HORs of non-existent states of awareness. In Charles Bonnet, syndrome, for example, people who are in fact blind have vivid and complex visual hallucinations. To deal with this, the authors propose to climb one order higher; the conscious awareness, they suggest, comes not from the HOR of a visual experience but from the HOR of a HOR: a HOROR, in fact. There clearly is no theoretical limit to the number of orders we can rise to, and there’s some discussion here about when and whether we should call the process introspection.
I’m not convinced by HOTs myself. The authors suggest that single-order theory implies there can be conscious states of which we are not aware, which seems sort of weird: you can feel fear and not know you’re feeling fear? I think there’s a danger here of equivocating between two senses of ‘aware’. Conscious states are states of awareness, but not necessarily states we are aware of; something is in awareness if we are conscious; but that’s not to say that the something includes our awareness itself. I would argue, contrarily, that there must be states of awareness with no HOR; otherwise, what about the HOR itself? If HORs are states of awareness themselves, each must have its own HOR, and so on indefinitely. If they’re not, I don’t see how the existence of an inert representation can endow the first-order state with the magic of consciousness.
My intuitive unease goes a bit wider than that, too. The authors have given a credible account of a likely process, but on this account fear looks very like other conscious states. What makes it different – what makes it actually fearful? It seems possible to imagine that I might perform the animal aversive behaviour, experience a conscious awareness of the threat and enter an appropriate conscious state without actually feeling fear. I have no doubt more could be said here to make the account more plausible and in fairness LeDoux and Brown could well reply that nobody has a knock-down account of phenomenal experience, with their version offering a lot more than some.
In fact, even though I don’t sign up for a HOT I can actually muster a pretty good degree of agreement nonetheless. Nobody, after all, believes that higher order mental states don’t exist (we could hardly be discussing this subject if they didn’t). In fact, although I think consciousness doesn’t require HORs, I think they are characteristic of its normal operation and in fact ordinary consciousness is a complex meld of states of awareness at several different levels. If we define fear the way LeDoux and Brown do, I can agree that they have given a highly plausible account of how it works without having to give up my belief that simple first-order consciousness is also a thing.