Clear limits to a baby’s view of the world

Young babies’ views of the world are far more basic than many believe. A new three-year research project funded by the Economic and Social Research Council suggests that babies are not born with as much innate knowledge of the world as some current studies suggest. “A great deal is claimed about what young babies know about the world but our findings favour a much more cautious approach,” states researcher Professor Gavin Bremner of the University of Lancaster. His research is published today as part of Social Science week. From Economic & Social Research Council:Clear limits to a baby’s view of the world

Young babies’ views of the world are far more basic than many believe. A new three-year research project funded by the Economic and Social Research Council suggests that babies are not born with as much innate knowledge of the world as some current studies suggest.

“A great deal is claimed about what young babies know about the world but our findings favour a much more cautious approach,” states researcher Professor Gavin Bremner of the University of Lancaster. His research is published today as part of Social Science week.

The study investigated the way in which babies up to six months old perceive objects. “As adults, we perceive a world composed of coherent, segregated objects,” explains Professor Bremner. “Also, as objects move we perceive them persisting even if they are temporarily hidden by other objects.” These abilities to fill in the gaps in perceptual experience are fundamental to human perception, but are we born with these abilities or do they develop in infancy? Moreover, do babies perceive the world in this way, or is their perception limited very much to what is literally visible at any one moment?

Researchers addressed these questions by testing how young infants perceive an object which moves from left to right but passes behind a screen at the half way point. Do the babies perceive it as a single object moving continuously, or do they see it as two separate movement segments?

“We carried out a series of studies to establish the conditions under which young infants perceived such movement events as continuous,” he explains. The first finding is that the width of screen is important: four-month-olds perceive trajectory continuity when the screen the object moves behind is narrow but not when it is wide. There is also a developmental effect: two-month-olds do not perceive trajectory continuity even when the screen is narrow, whereas a baby at six months perceives continuity even when the screen is wide. Further investigation reveals that four-month-olds perceive an object as moving continuously only when it is out of sight for a short distance (ie a narrow screen) or for a short period of time.

“These findings are important because they cast doubt on nativist claims that babies are born with some sort of innate pre-wiring that means awareness of objects is well developed at birth,” Professor Bremner points out. “In fact, our results suggest a very different developmental process from that presented by nativists,” he adds. Rather than concluding that perception of the identity and permanence of moving objects is present at birth, it seems apparent that babies initially do not see objects that move behind a screen as moving on a continuous path. And by four months they do so only under tightly constrained conditions. “This suggests that babies develop their perceptual abilities with age but are not born with them,” he concludes.