25.05.2018 change 25.05.2018

Infants are capable of drawing logical conclusions

Photo: Fotolia Photo: Fotolia

Language is not necessary to apply logic. One year old babies are able to draw logical conclusions, say the authors of the new study published in "Science". In a situation inconsistent with logic, small children show greater interest than when everything is in order.

According to cognitive theories, the ability to formulate and test hypotheses is an advanced ability of a more mature brain capable of using language. "We show that the ability to formulate and test hypotheses is not language dependent, it occurs already in 12-month-old infants" - Ryszard Cetnarski, a doctoral student at the Institute of Experimental Biology PAS comments in an interview with PAP.

He is a co-author of the study presented in "Science" http://science.sciencemag.org/content/359/6381/1263. The research team leader was Nicolo Cesana-Arlotti from the Pompeu Fabra University in Barcelona.


The experiment was conducted on three groups: children aged 12 months, 19 months and adults. Participants watched videos showing situations consistent with logic, and ones in which something strange, illogical was happening. Researchers used eye-tracking to compare eye movement of the subjects and the size of their pupils while they watched the two videos.

One of the videos shown to children shows two different toys, for example a dinosaur and a flower. After a while, one of the toys - the flower - is hidden in a cup, but you can still see its fragment. Then, the flower is pulled out of the cup and you can see it in all its glory. Surprising? Hardly, everything is logical.

But the subjects were also shown the second version of the videos. The flower is hidden in the cup again (its fragment still in view), but after pulling the toy out of the cup, it turns out that it is... another dinosaur! The end of the video does not show the flower and the dinosaur (shown in the beginning), but two dinosaurs. It`s against logic!


Researchers who observed the reactions of the examined children say that even 12 months old babies noticed something strange in the second video. Researchers were able to determine that because children would stare longer at the second dinosaur. Or they would switch faster between looking at each dinosaur than they switched between looking at the flower and the dinosaur when watching the logical movie. In addition, after watching this strange toy swap, the children`s pupils dilated. A similar reaction was observed in older children and adults watching the same video.

"If the eyes behave differently while watching a logical story compared to watching an illogical story - for example, the pupils dilate. It may mean that different processes take place in the brain" - sums up Ryszard Cetnarski.

"Our results suggest that the ability to learn by testing hypotheses is a basic, language-independent way, in which the mind functions" - says Ryszard Cetnarski.

The doctoral student describes the logical reasoning during the experiment. A child sees a toy fragment protruding from a cup and formulates the hypothesis of what is in this cup. "If the child sees the dinosaur next to the cup, it expects the flower to be in the cup" - describes the researcher. And he adds that language allows us to verbalize the problem, describe it.

In the experiment, however, researchers point out that verbalization is unnecessary in logical reasoning. An illogical event - a toy switch - is noticed even by babies who do not yet have the command of language.


The research conducted by the international team has contributed to the scientific "nature vs nurture" debate on whether cognitive abilities are innate, or derived from learned cultural processes, such as language. "This study would suggest that people are able to think logically already thanks to their innate traits, and not only because of developed language and culture" - interprets the cognitivist.

He adds that the conclusions from the research project can probably be also applied to other organisms, not only to people. "But we have not tested it on animals yet" -notes the PhD student.

PAP - Science in Poland, Ludwika Tomala

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