#208 The Brain’s Multi-Sensory Shortcuts

The Brain

The brain and the senses operate as a combined system. Their job is to allow us to recognize something as quickly and efficiently as possible. To do this the brain holds patterns that involve more than one sense.

A Five-Minute Read.

The Hidden Patterns.

A simple test to start with. Look at the pictures. Here are two nonsense words: “bouba” and “kiki”. Which word would you associate with which shape? Across many studies the same answer emerges. (See footnote for answer). This is known as the bouba-kiki test. It has been proven in 23 different languages and many different scripts.

It illustrates how the brain can associate a shape and a sound. It is one of the earliest detected linkages. There are many other examples. They are known as cross modalities. This is because they associate different things across different senses. People will associate a high-pitched sound with a small bright object. More than 80 years ago, Edward Sapir observed a different pattern. Most people associate the nonsense words “mal” and “mil” with large and small objects, respectively.

Building the Shortcuts

There are multiple theories about the origins of such linkages. They enable the brain to more quickly assimilate a range of signals from the different senses. In evolutionary times “putting the picture together” was crucial. It meant the difference between having lunch and being someone else’s lunch.

It is much more difficult to ignore a distraction if it is a cross-modal link with the tasks. It is much easier to respond to large visual stimuli and low tones and smaller visual stimuli and higher tones. When the mapping of stimuli reverses it is much more difficult to do a selection task.

Cross-modal correspondences do improve the speed and accuracy of our perception. It seems to operate automatically. A lot of these linkages come from association. If they appear together, often in the real world, the brain “files” that association. Some linkages can come from the similarity in sounds between objects. We associate “light” with both a visual stimulus and a touch sense of weight. Neuroscientists suggest that some linkages may come from the proximity within the brain of centres processing the signal.

The Impact of Age

There are two schools of thought about the impact of age on cross-modal associations. The first argues that the senses have higher thresholds as we age. At the same time, we may be losing cognitive ability. The result “must” be a decline in cross-modal ability. There is a counter argument. That cross-modal associations strengthen to counteract the sensory decline. To fill in the gaps.

A recent study shows the complexity of the issue. They compared young and old respondents and their visual and touch senses. The touch sense stimulus was a braille simulator. It pushed a block of eight pins onto the index figure. They could vary how high the push was and the pattern of the pins. The visual stimulus was a picture of the same layout and number of pins. Picture contrast could be varied by adjusting the background. The respondent’s job was to say when the pattern on their finger matched the pattern on the screen.

The results highlighted that the thresholds of the older people were higher. Particularly their sense of touch. The lowered the pins and increase the contrast untl the stiuls could not be discerned. With both visual and tactile stimulus set at the (low) threshold level, the cross-modal performance was worse for the older group. However, if the stimulus was increased the older group could match the younger group. This suggests that the effect may not depend on cognitive ability. It could instead depend on the ability to focus attention.

Cross Modal Congruence In-Store

These effects are being studied within the business world. Consumer behaviour researchers have used cross modal congruency to design retail spaces. Soft music can make a sweater feel softer. Bright lighting is associated with lighter products. Shelving needs to be adjusted. A scent that matches the theme of a store can enhance the impact. Lavender is better suited to soft decor than lemon scent.

Answer: “bouba” is associated with the softer “cloud like” shape by 90% of people.

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