Babies really do see the world differently, researchers have found, after revealing that those under six months old do not fall for a visual illusion that can trick older children and adults.
Experts say that is because information processing in the tots’ brains is not yet fully developed, which means they make different assumptions about what they see.
Writing in the journal Proceedings of the Royal Society B, researchers in Japan report how they showed a screen featuring red and green dots to infants aged five to eight months.
Dots of one colour moved upwards in the centre but downwards on the right and left, while dots of the other colour showed the reverse motion.
When adults look at the centre of the screen, a visual illusion occurs: the red dots all appear to move in one direction and the green dots in the other.
To explore whether this also occurs for infants, the team presented children with a screen with dots of just one colour. These either all moved in the same direction or moved in one direction in the centre and the opposite direction at the sides.
Data from 40 infants revealed that those younger than six months spent longer looking at the screen when the dots all moved in the same direction, while older infants spent longer looking at the screen when the dots moved in both directions.
As infants tend to look longer at unfamiliar things, experts say the results suggest the older infants perceived the initial illusion but not the younger ones.
“[Younger infants] perceived the accurate combination between colours and motion directions,” said Dr Shuma Tsurumi, a co-author of the research from Hokkaido University.
Prof Paul Bays, of the University of Cambridge, who was not involved in the work, welcomed the findings. He said that what we see was influenced by expectations about the world embedded in our brains during development.
“This makes us susceptible to visual illusions, when the context leads us to expect to see something different from the reality. In this case, the illusion arises because the adult visual system assumes what you see in the centre of the screen is a good guide to what’s happening at the periphery,” Bays said.
“[The results are] consistent with the idea that younger babies have not yet built up the expectations about the world that create the illusion,” he added.
Dr Alice Skelton, of the University of Sussex, said it was not that young babies see the world more accurately, but rather that what it is helpful to perceive changes with age.
“We often talk about how poor infant vision and perception are in comparison with adults, but they’re sensitive to all sorts of different parts of the world that we no longer have access to as adults,” Skelton said.
