Thursday, November 4, 2010

Seeing is Felieving?? What's causing what?



The McGurk Effect -- what you see is what you hear.

10 comments:

John said...

As a cognitive psychologist, it is not the McGurk Effect that is odd or needs explaining, but rather that most people seem to see the need for an explanation. What are they assuming about the nature of perception that would lead them to see the McGurk Effect as odd as opposed to just what one would expect? Rather than provide an introduction to cognition and perception here, I would be interested to hear what people are assuming that makes them find this effect "odd", or inconsistent with what they think about perception and cognition.

Anne Buchanan said...

To me, this isn't something that needs explaining any more than any other aspect of perception. It's that we've thought in terms of 5 separate senses since Aristotle and this makes it starkly clear that perception is more complex than that, that our senses aren't working independently of each other but that the brain makes sense of a lot of incoming information at once -- and sometimes not all that accurately. This shouldn't be a surprise, as you say, but those of us who aren't cognitive psychologists are likely to be stuck at the level of what we learned in grade school about perception and the senses, and so it is.

Here's where your introduction to cognition and perception would be helpful.

Anne Buchanan said...

A reader on our Facebook page suggests that perhaps the McGurk effects means that the senses are hierarchical, sight trumps hearing, hearing trumps something else. Any thoughts on this?

He also says "It would be fun to try the experiment using still pics and sound, i.e., mouth in 'f' shape and 'b' shape pics, playing the ba, ba, ba sound, and see what the reaction is. Is the perception of motion, which might adjust expectations, in play?"

Surely this experiment has been done?

Ken Weiss said...

I find it interesting in terms of the ordinary person's (and in this area, I'm one such) idea that the senses are separate and by themselves. Maybe the general public, even the general 'educated' public should know a lot more than we've been taught.

James Goetz said...

Evidently, hallucinations can trump all perceptions. Unfortunately, I suppose this branch of psychiatry is way out of all of our leagues. Are any research psychiatrists reading this?

Per a previous post, rats, I was counting on B12 preventing dementia in old age.

Anne Buchanan said...

Well, Jim, maybe next week's study will show a positive effect of B12, so you may as well not stop taking it. Could be the placebo effect is as good as anything here!

James Goetz said...

"As a cognitive psychologist, it is not the McGurk Effect that is odd or needs explaining, but rather that most people seem to see the need for an explanation. What are they assuming about the nature of perception that would lead them to see the McGurk Effect as odd as opposed to just what one would expect?"

From my perspective, I like to think that I can trust my senses. So I suspected it was a bah! humbug! hoax until I saw the side-by-side lipsync. After I understood the effect, I felt a little insecure about the reliablilty of my sense of hearing, which I depend upon for many things.

Regardless, I recall a motion effect. A video from the perspective or a roller coaster car can cause the feeling of motion.

G Greene said...

In response to John - if I count myself among 'most people', what I find interesting/odd is that as much as we know about how unreliable, not that our senses are, but our *interpretation* of our sensory input, most of us still amble about largely convinced that our experience and understanding of the world is pretty much on target, i.e., is 'real'. (So I think what people are assuming about the nature of perception is that it's an accurate representation of the 'real' world.) For example, though it is universally accepted that eyewitness testimony is unreliable, how many times do we personally remain convinced that *our* recollections are spot on? What most interests me about the McG effect is not the effect itself, but the novelty of being surprised about something that, in retrospect, shouldn't surprise me at all. Who among us hasn't experienced the phenomenon of being proven objectively wrong about an event or situation or set of facts, despite our implacable belief we're right? (Sometimes simple repetition does it. 80% of Americans believe, due to the endless repetition of a falsehood, that Obama started the bailouts, when it was Bush with TARP, and many of that 80% would now refuse to believe otherwise, even presented with the facts.) After all, the senses are nothing more than the *initial input* into a long chain of events/processes that allow us to perceive, categorize, remember and react to the world around us. As the saying goes, 'I'm often wrong, but never in doubt'. What's fun about the McG effect isn't that it exists, it's that, like a baby with a set of keys dangled ion front of it, we're surprised (and sometimes delighted) at each subsequent demonstration.

Ken Weiss said...

There may be a related lesson here, one that we carp on a lot. That is that causation may not be as simple or clear-cut as we like to think, or hope it is. Our concern has to do with interpretation of evolution and genetic effects, but the issue may apply quite broadly.

James Goetz said...

In light of evolution, I'll conjecture that human brain development related to imagination, abstract thought, dreaming, hallucinations, and religious experiences has made humans overall more adaptive regardless if there are byproducts that can cause occasional deception of senses such as the McGurk Effect.