Take a look at the following movie. Your job is to identify which ball appeared to make the noise in the final frame. (click to play):
If this seems confusing now, it should be cleared up by the end of this post. You can register your result in this poll:
Synesthesia, as we’ve discussed before, is a rare condition. Synesthetes are people who perceive stimuli presented in one mode (often corresponding to one of the five senses) with a different mode. It’s a remarkable ability, manifesting itself in a variety of different ways — seeing “auras” around friends, or associating a sound or even a taste or a smell with certain types of visual images.
But how do people become synesthetes? One intriguing explanation is that we all start out that way: as babies, the sensory organs activate areas all around our brains, and only as we grow older do we specialize, by “pruning” neural connections, so images are processed in the visual cortex, sounds in the auditory cortex, and so on. Synesthetes, in this model, fail to prune as many of those connections as normal individuals, and thus retain some of their infant perceptual abilities.
Catherine J. Mondloch and Daphne Maurer have developed a series of experiments to see if very young children might show some evidence of synesthesia.
First, they showed 30-month-olds pairs of animals or objects and made a sound from a central speaker. For example, one picture was an elephant and a lion. Either a lion’s roar or an elephant’s trumpet was played, and the child was asked to point to the animal that made the sound. This was done to make sure the children understood the task, and all of the children could repeat this task at least three out of four times, with different pictures each time.
For the actual test, the children were shown a pair of bouncing balls — one small and white, the other large and gray. The balls both bounced simultaneously. As the balls bounced, they made either a 256 Hz tone (Middle C), or a 512 Hz tone (one octave higher). This was repeated four times, alternating between the high tone and the low tone. Finally, the balls were shown bouncing with either the high or low tone and the child was instructed to point to the ball that made the sound. Eleven out of the 12 children said that the small white ball made the high-pitched tone or the large gray ball made the low-pitched tone.
In new experiments, the process was repeated, but varying only the size or the color of the balls. In one task, the balls were the same size, with one white and one gray. All twelve children said the gray ball made the low-pitched sound or the white ball made the high-pitched sound. In the second task, both balls were white, but one was bigger than the other. In this task the results were less clear-cut. It took 24 children to obtain a significant result: 19 of the 24 children said the larger ball made the low sound or the small ball made the high sound.
This result corresponds to responses by adult synesthetes: small, bright objects make high-pitched sounds, while large, dark objects make low-pitched sounds. Mondloch and Maurer point out that while their result is consistent with the hypothesis that all newborns are synesthetes, it doesn’t prove it. The research does, however, offer an intriguing glimpse into the nature of infant perception.
Mondloch, C.J., & Maurer, D. (2004). Do small white balls squeak? Pitch-object correspondences in young children. Cognitive, Affective, & Behavioral Neuroscience, 4(2), 133-136.