Psychedelic world

by: Paula Parungao

Have you ever heard of people hearing color or seeing sound? No? That's because only 4% of the entire population have this kind of disorder, when their perception of the world (at least, to us "normal" individuals) are kinda mixed up. This condition, when perceptions are mixed up is called synaesthesia.

One study aimed to understand in part how synaesthesia works. The researchers focused only on those individuals that have colored-speech. That is, those who can see color when words are presented to them. Imagine being able to see color when speech is perceived. Man, that'd make for one psychedelic world! Anyway, so these people decide to get twelve participants who had synaesthesia (1 male, 11 females); with this condition so rare, I'm surprised they got this many participants.

For the experiment, the researchers recorded an actor saying words with the use of the McGurk Illusion. What's the McGurk Illusion? We all know that perception of speech doesn't only occur in our auditory field. Our vision also contributes a lot on how we perceive what other people are saying. This is what the McGurk Illusion is trying to manipulate with. When someone is presented with a person who is saying "baba" but he looks like he's saying "gaga" then that someone then perceives the word to be "dada", which is in the middle of the two letters in terms of word articulation. Try saying "gaga", "baba" and "dada". C'mon, try it. You won't see my point if you don't. Done? Notice how you said "gaga". The articulation was at the back of the mouth, right? Where was the articulation of the other two? I won't tell you. You just have to guess. Moving on to the experiment...

The synaesthetes were presented with audiovisual stimuli, audio stimuli and visual stimuli with the McGurk Illusion in effect, meaning the recorded sound was different from how the actor visually articulated them. In audiovisual stimuli, the actor's face was shown and the audio was heard. In audios stimuli, the actor's face was blurred, and in visual stimuli, the audio was masked in white noise. What the researchers were trying to find out was when synaesthetes experience color. As expected, individuals reported the audio-only condition correctly in most of the trials, consistent with the McGurk Illusion; they also experienced color. So that means audio-only condition may be a part in inducing synaesthesia. Audiovisual condition also reported color. Check. The visual condition, not very surprisingly but very interestingly, produced no color in synaesthetes, which suggests that visual information alone wasn't enough to perceive the sensation of color. What's also interesting to note is that audio-only conditions and audiovisual conditions produced different colors. Meaning different perceived letters have their own color.

These findings led the researchers to suggest that synaesthetes may actually have higher levels of perception, meaning that these individuals get feedback from the higher-order areas of the brain, for example, the color area, to the earlier areas, like the visual area. The researchers then concluded that synaesthesia, at least of colored speech, isn't limited to the audio and visual areas of the brain. It's more of an abstract, multidimensional interaction that we "normal" people have yet to understand.

References:

Bargary, G., et al. (2009). Colored speech synaesthesia is triggered by multisensory, not unisensory perception. Psychological Science. Vol.20, 5, 529-533.