Ineffable mutterings of a science student: Monkeys and Touchscreens

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Give an infinite number of monkeys an infinite number of typewriters and they will mostly just pull the keys off and cover them in faeces. But give a finite numb er of monkeys four touchscreen computers and they could learn to distinguish words from nonsense, according to a new study published in Science last week.

Led by Dr. Jonathan Grainger, a team of researchers at Aix-Marseille University in France trained six adolescent Guinea baboons to differentiate between four-letter English words, such as “done”, “them” and “vast”, and four-letter non-words, such as “dran”, “telk” and “virt”. The baboons had free access to four touch-sensitive computer screens within their enclosure, and on these screens would flash either a real word or a non-word. The monkeys were tasked with categorising these letter sequences by touching either a cross or an oval on the screen, with each correct answer earning them a food reward.

Over the course of a month and a half, the baboons learnt to distinguish dozens of words – one, called Dan, ended the experiment with a vocabulary of 308 words – from over 7800 non-words with an average of 75%.

This is particularly impressive given that the non-words used in the experiment strongly resembled the actual words; each consisted of one vowel and three consonants. Most remarkably, the monkeys weren’t only memorising the words that they had already been shown; even words that were seen for the first time were less likely to be categorised as non-words than actual non-words.

Grainger thinks that the baboons learnt to differentiate between words and non-words by looking at the positions of the letters within them relative to the other letters – a technique known as “orthographic processing”. If a baboon was shown a sequence of four letters that contained an unusually ordered combination, it was more likely to categorise it as a non-word than a word, suggesting that the monkey had learnt general patterns of letter combinations in real words.

These findings suggest that the ability to recognise and process written language relies on cognitive mechanisms that are much more ancient than written word itself; perhaps unsurprising, given how recently in our history this linguistic innovation came about. As Grainger and his team conclude, the primate brain might “be better prepared than previously thought to process printed words, hence facilitating the initial steps toward mastering one of the most complex of human skills: reading.

Heather Stevens

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PHOTO/Oliver Hammond