Seated in a monitoring room at the Harvard University Laboratory for Developmental Studies in Massachusetts,US,Dr Elizabeth S Spelke,a professor of psychology,looked on expectantly as her students prepared a boisterous eight-month-old girl with dark curly hair for the onerous task of watching cartoons. The video clips featured simple Keith Haring-type characters jumping,sliding and dancing from one group to another. The researchers objective,as with half a dozen similar projects under way in the lab,was to explore what infants understand about social groups and social expectations. Yet even before the recording began,the 15-pound research subject made plain the scope of her social brain. She tracked conversations,stared at newcomers and burned off adult corneas with the brilliance of her smile. Spelke,who first came to prominence by delineating how infants learn about objects,numbers,the lay of the land,shook her head in astonishment. Why did it take me 30 years to start studying this? she said. All this time Ive been giving infants objects to hold,or spinning them around in a room to see how they navigate,when what they really wanted to do was engage with other people! The lab Spelke,62,founded with her colleague Susan Carey is strewn with toys and childrens T-shirts,but the atmospherics belie both the labs seriousness of purpose and Spelkes towering reputation among her peers in cognitive psychology. She is trying to identify the bedrock categories of human knowledge. She is asking,What is number,space,agency,and how does knowledge in each category develop from its minimal state? said Steven Pinker,a fellow Harvard professor and the author of The Better Angels of Our Nature,among other books. Spelke studies babies not because they are cute but because they are root. Ive always been fascinated by questions about human cognition she said,and why were good at some tasks and bad at others. But the adult mind is far too complicated,she said. In her view,the best way to determine what,if anything,humans are born knowing,is to go straight to the source,and consult the recently born. Spelke is a pioneer in the use of the infant gaze as a key to the infant mindthat is,identifying the inherent expectations of babies as young as a week or two by measuring how long they stare at a scene in which those presumptions are upended or unmet. Here,according to the Spelke lab,are some of the things that babies know,generally before the age of 1: They know what an object isa discrete physical unit in which all sides move roughly as one,and with some independence from other objects. If I reach for a corner of a book and grasp it,I expect the rest of the book to come with me,but not a chunk of the table, said Phil Kellman,Spelkes first graduate student,now at the University of California,Los Angeles. A baby has the same expectation. If you show the baby a trick sequence in which a rod that appears to be solid moves back and forth behind another object,the baby will gape in astonishment when that object is removed and the rod turns out to be two fragments. The visual system comes equipped to partition a scene into functional units we need to know about for survival, Kellman said. Babies know,too,that objects cant go through solid boundaries or occupy the same position as other objects,and objects generally travel through space in a continuous trajectory. Babies are born accountants. They can estimate quantities. Show infants arrays of,say,four or 12 dots and will match each number to an accompanying sound,looking longer at the four dots when they hear four sounds than when they hear 12 sounds,even if each of the four sounds is played comparatively longer. Babies can also perform a kind of addition and subtraction,anticipating the relative abundance of groups of dots that are being pushed together or pulled apart,and looking longer when the wrong number of dots appears. Babies are born Euclideans. Infants and toddlers use geometric clues to orient themselves in three-dimensional space,navigate through rooms and locate hidden treasures. At the same time,the Spelke lab discovered,young children are quite bad at using landmarks or decor to find their way. Not until age five or six do they begin augmenting search strategies with cues like She hid my toy in a corner whose left wall is red rather than white. That was a surprise to me. My intuition was,a kid would never make the mistake of ignoring information like the colour of a wall, she said. More recently,Spelke and her colleagues have begun identifying some of the baseline settings of infant social intelligence. Katherine D Kinzler,now of the University of Chicago,and Kristin Shutts,now at the University of Wisconsin,have found that infants just a few weeks old show a liking for people who use speech patterns the babies have already been exposed to,and that includes the regional accents,twangs,and Rs or lack thereof. In guiding early social leanings,accent trumps race. A white American baby would rather accept food from a black English-speaking adult than from a white Parisian. Spelke has proposed that human language is the secret ingredient,the cognitive catalyst that allows our numeric,architectonic and social modules to swap ideas and take us to far horizons. She points out that children start integrating what they know about the shape of the environment,their navigational sense,with what they know about its landmarksat the age when they begin to master spatial language and words like left and right. Yet,she acknowledges,her ideas about language as the central consolidator of human intelligence remain unproved and contentious.
