Infants' coding of location in continuous space

The ability to code location in continuous space is fundamental to spatial behavior. Existing evidence indicates a robust ability for such coding by 1 2 months, but systematic evidence on earlier origins is lacking. A series o f studies investigated 5-month-olds' ability to code the location of an obj ect hidden in a sandbox, using a looking-time paradigm. In Experiment 1, af ter familiarization with a hiding-and-finding sequence at one location, inf ants looked longer at an object being disclosed from a location 12 inches ( 30 cm) away than at an object emerging from the hiding location, showing th ey were able to code location in continuous space. In Experiment 2, infants reacted with gn ater looking when objects emerged from locations 8 inches (20 cm) away from the hiding location, showing that location coding was mor e finely grained than could be inferred based on the first study. In Experi ment 3, infants were familiarized with an object shown in hiding-and-findin g sequences at two different locations. Infants looked longer at objects em erging 12 inches (30 cm) away from the most recent hiding location than to emergence from the other location, showing that infants could code location even when events had previously occurred at each location. In Experiment 4 , after familiarization with two objects with different shapes, colors, and sounding characteristics, shown in hiding-and-finding sequences in two loc ations, infants reacted to Location violations as they had in Experiment 3. However, they did not react to object violations, that is, events in which the wrong object emerged from a hiding location. Experiment 5 also found n o effect of object violation, even when the infants initially saw the two o bjects side by side. Spatiotemporal characteristics may play a more central role in early object individuation than they do later, although further st udy is required.