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Even toddlers can calculate probabilities
At the age of six months, children develop a sense of statistics
One of the most important abilities of our brain is to draw general conclusions about our environment from a few existing data in order to avoid as many uncertainties as possible. It constantly estimates how likely an event is and thus recognizes statistical regularities. As adults, we have a rough idea of the likelihood of different events. So far, however, it was unclear from what age we are able to estimate probabilities. Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig have now shown: Already six-month-old babies have a feeling for probabilities.
For a lifetime we have to make decisions again and again and weigh the odds against each other. By learning to gauge which event is more likely to happen than another, we become better at assessing risks and aligning our actions accordingly. But at what age do we begin to develop a sense of the stochastics of events? Are babies already able to do this??
Study showed that toddlers are able to assess probabilities. (Image: Dan Race / fotolia.com) Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig and the University of Uppsala, Sweden, have now discovered that babies as young as six months old can evaluate probabilities. The little ones are already able to filter out of a crowd of blue and yellow balls, which color is the more common and therefore the one that is more likely to be drawn. "The ability to estimate probabilities seems to evolve around the age of six," said Ezgi Kayhan, a neuroscientist at the Max Planck Institute in Leipzig and head of the underlying study. In a previous study, four-month-old babies could not solve this task yet. They therefore do not seem to be sensitive to probabilities yet.
The neuroscientists studied these relationships using animated films, which showed a total of 75 babies at the age of six, twelve and 18 months. In it was a machine filled with a lot of balls, many of them blue, a few yellows - like a lottery machine. This spat in a basket many of the main blue balls, in a second, however, many yellow balls. That the machine spits out a yellow instead of a blue ball was 625 times more unlikely. The second container full of yellow balls thus reflected an event that occurs only with extremely low probability.
While the babies watched the short films, researchers used the so-called eye-tracking method to see which of the two baskets the little subjects were looking at longer-the more likely or the less likely. "We've found that babies, no matter what their age, looked longer in the unlikely variety. Presumably they were amazed that it consisted mainly of the very few existing yellow balls, so it was a very unlikely event, "said the researcher. In order to make sure that the little ones did not only feel more attracted to the yellow color, in some of the experiments the scientists turned over the frequencies of both colors or used green and red balls.
Changed probabilities
"In principle, there have already been some studies on whether infants are able to estimate probabilities. However, we were the first to explore the limitations of this early ability, "explains Kayhan. To do this, she and her team tested whether it makes any difference how clearly the difference between the likely and the unlikely variant can be seen at first glance. And indeed: When the researchers changed the ratio of blue and yellow spheres and thus the chances of pulling one of the two colors, the eyes of the little ones also changed. If it was only nine times more likely that the machine spit out a blue instead of a yellow ball, the small study participants suddenly looked longer at the more probable variant, the basket with primarily blue balls.
"One explanation for this observation might be that as your level of difficulty increases, information for the little ones above a certain level becomes too complex. From previous studies, we know that babies focus on cases they know about objects or contexts where they do not have enough time to process new and complex information, "says Kayhan. "Once they have decrypted them, they can devote themselves to new things." Regardless of a possible explanation of the scientists on the basis of the results, one thing was clear: Whether babies can handle probabilities depends not only on their age, but also of the Ratio between a probable and unlikely event. VM / HR