A new study has revealed that babies do not understand information that is too simple or too complex and instead ingest information that is "just right".
Dubbed the "Goldilocks effect" by the University of Rochester team that discovered it, the attention pattern sheds light on how babies learn to make sense of a world full of complex sights, sounds, and movements.
The findings could have broad implications for human learning at all ages and could lead to tools for earlier diagnosis of attention-related disabilities such as ADHD or autism, said Celeste Kidd, lead author on the paper and a doctoral candidate in brain and cognitive sciences at the University.
The research is the first to provide both a theory and quantifiable measures of what keeps a baby's attention, stated coauthor Richard Aslin, the William R. Kenan Professor of brain and cognitive sciences at the University.
For years, researchers have explored what types of events most effectively capture babies' attention. In some situations, infants reliably prefer familiar items, such as a favourite toy; in others, they favour novel objects.
The new study resolves such seeming contradictions. Instead of novelty or familiarity per se, the research showed that babies seek out situations with just the right amount of surprise or complexity.
To measure complexity, the Rochester team developed a test based on the probability of surprising events in a video.
In the study, researchers measured the attention patterns of 72 seven- and eight-month-old infants in two separate experiments. The babies watched video animations of fun items, such as a pacifier or ball, being revealed from behind a set of colourful boxes. The researchers varied where and when the objects would appear across dozens of short trials.
To measure attention, an eye-tracking device located below the computer screen followed the infants' gaze. As long as they looked at the screen, the events continued; as soon as they looked away, the trial ended. Babies quickly learned that they were in control. If they wanted to continue watching they just needed to keep their eyes on the screen.
To reduce distractions, infants sat in a darkened space on the lap of their parent, who wore headphones playing music and a visor to prevent them from biasing their infant's performance.
Using a specialized statistical model, the researchers were able to calculate and predict how likely infants were to lose interest based on the complexity of each event depicted in the video. Complexity was defined as how surprising each event was in light of the previous events an infant had observed in the video.
Across both experiments, babies reliably lost interest when the video became too predictable - when the probability of a subsequent event was very high.
"But here's the counterintuitive part. You would think that the more complex something is, the more interesting it would be. That's not the case with babies," Aslin asserted.
They drifted away from the screen when the sequence of events also became too surprising - when the pattern seemed random and unpredictable because the probability of something happening was very low.
"The study suggests that babies are not only attracted by what is happening, but they are able to predict what happens next based on what they have already observed. They are not passive sponges. They are active information seekers looking for the best information they can find," Kidd said.
Although the experiments were limited to infants, the results provide a window into the way the brain works in general.
The study will be published in the journal PLoS ONE.