Object-based visual attention in 8-month-old infants: evidence from an eye-tracking study

Visual attention is one of the infant's primary tools for gathering relevant information from the environment for further processing and learning. The space-based component of visual attention in infants has been widely investigated; however, the object-based component of visual attention has received scarce interest. This scarcity is surprising, given the importance of objects in driving infants' attention and predispositions to attend to object information. Here, we investigated the object-based component of attention in 8-month-old infants. An eye tracker measured the saccade latencies to find a target that could appear in a previously cued end of 2 bars (valid targets), in the other end of the cued bar (invalid same-object targets), or in the other bar but at the same distance from the cue (invalid different-object targets). Bars were unoccluded or partly occluded; if attention is object based, it should also operate on objects that require perceptual completion. After verifying in a sample of adults (Experiment 1) that a measure of saccade latency suitably assessed space-based and object-based attention, we tested 8-month-old infants (Experiment 2) using the same procedure. The results showed that in both adults and infants, target detection was faster for valid targets than for invalid ones (space-based effect). Moreover, for both the unoccluded and partly occluded conditions, detection was faster on invalid within-object trials than on invalid between-objects trials (object-based effect). These findings demonstrate that visual objects can operate as units of attention for infants by the age of 8 months, offering implications for cognitive development.