Wednesday, 10 July 2013

Why most people don't see ghost ducks

Duck on a bridgeWhen I looked up I saw a duck perched on a wall. It wasn't that unexpected, given that the road bridge spanned a slow moving river frequented by ducks! The 'duck' only lasted a second or so before, like a ghost, turning into something quite different. I took photos to check out my misperception in detail later. The one here, right, shows roughly what I first saw. If you look at the top of the wall, the 'duck' is the orangey-brown object roughly halfway along. From this photo, the object could be almost anything. So why did I think it was a duck, and why would most people disagree?

On a wider point, why do people sometimes report seeing human figures (or ghosts) which are really bushes or trees but never the other way round? I've not heard of anyone seeing a human figure as a bush and I don't recall doing it myself. That doesn't mean it can't happen. It may simply not be noticed. And this may be throw light on why the overwhelming number of ghosts reported are human figures while only a few are animals or ghostly objects.

To understand why we are more likely to see bushes as people, rather than the other way round, it is worth considering prosopagnosics, who cannot recognise people's faces (including their own in some cases). Around 2% of the population have this condition of face blindness. And yet many people who have it are not even aware of it. That's because, unconsciously, they learn to recognise people through things other than their faces, like clothing, voice, hair, behaviour, context (where and when seen, for instance) and so on. It's a bit like using jizz (see here).

Brain scans show that certain areas of the brain are used in recognizing faces. One, in particular, the fusiform gyrus (FG) appears particularly important, though there are others involved too. But while the FG is heavily implicated in face recognition, it also is used to recognise objects in which the observer is expert. For instance when a keen birder sees a bird, such as a duck! Interestingly, the FG also responds, though weakly, to objects that simply resemble faces! Or, in my case, perhaps to an object that resembles a duck!

There is a still a debate, not yet entirely settled, in neuroscience about whether we recognise faces through some in-built 'modules' in the brain (like the FG) or by developing an 'expertise' for the problem through experience. Whatever the answer, it is clear that we have, or develop, an ability to recognise faces, and other objects we have a particular interest in.

The fact that the FG responds to objects that resemble faces may explain while people report seeing apparent faces in photographs and report them as ghosts, something which has puzzled me for a long time. In many such cases it is clear that the 'face' is just an accidental pattern - a simulacrum - so why is it ever reported as a ghost? Certain people may, on seeing an object in a photo that resembles a face, react to it as if it was a person. Since it is obviously not a person, they may conclude it is a ghost! See also here for an example of photographic ghostly faces that not so obviously accidental.

Duck on bridge closerAnyway, back to the original point! The second photo I took, right, was a telephoto version of the same scene. It is now possible to see that the brown object is a collection of senescent leaves, on a branch, overhanging the wall. It still looks a bit odd and does have a vague duck shape but that isn't what most people would see. I saw a 'duck' because I'm a birder. I guess the object stimulated my FG! Also, in my defence, there is a big difference between glancing briefly at an object with the naked eye and being able to study it at leisure in a photo.

So why don't we get reports of people being misperceived as bushes? I think this may come down mainly to context. A person might, indeed, be mistaken for a bush in a forest, if they are stand very still in suitable clothing, but it's unlikely a witness would notice them. One more bush in a forest is not really noteworthy. But a bush appearing like a person in a forest would be much more likely to attract attention. That's because the presence of another human in a forest is important to the witness. They could represent a potential threat, for instance, or assistance if the witness is lost. Or the witness may simply be curious about the presence of the other person. The fact is, as people, we are much more interested, in general, in other people than bushes or other inanimate objects and we tend to notice them.

So, while we may well misperceive either way, we're much more likely to notice objects seen as human figures. It would be interesting to know if those few people who've seen animal ghosts were especially interested in animals. I suspect this will turn out to be the case. I can confirm that birders have mistaken some pretty unlikely objects for birds, something that would probably never happen to a non-birder. Which is why you almost certainly didn't see the object on the bridge as a duck, ghostly or otherwise!

No comments:

Post a Comment