Free viewing biases for complex scenes in preschoolers and adults.

Adult gaze behaviour towards naturalistic scenes is highly biased towards semantic object classes. Little is known about the ontological development of these biases, nor about group-level differences in gaze behaviour between adults and preschoolers. Here, we let preschoolers (n = 34, age 5 years) and adults (n = 42, age 18-59 years) freely view 40 complex scenes containing objects with different semantic attributes to compare their fixation behaviour. Results show that preschool children allocate a significantly smaller proportion of dwell time and first fixations on Text and instead fixate Faces, Touched objects, Hands and Bodies more. A predictive model of object fixations controlling for a range of potential confounds suggests that most of these differences can be explained by drastically reduced text salience in pre-schoolers and that this effect is independent of low-level salience. These findings are in line with a developmental attentional antagonism between text and body parts (touched objects and hands in particular), which resonates with recent findings regarding 'cortical recycling'. We discuss this and other potential mechanisms driving salience differences between children and adults.

Do infants show knowledge of the familiar size of everyday objects?

The current study aimed to examine the age at which infants exhibit knowledge of the familiar size of common everyday objects. A total of 65 7- and 12-month-old infants were presented with familiar-sized and novel-sized (i.e., larger or smaller than the familiar size) common everyday objects (i.e., pacifiers and sippy cups), which were placed out of their reach. Both 7- and 12-month-olds' first looks were more frequently directed toward physically larger objects irrespective of whether they were familiar- or novel-sized objects. This finding indicates that initial visual orientation is contingent on the magnitude of the absolute physical size of an object. However, when the entire duration of presentation of the objects (i.e., 10 s) was examined, 12-month-olds' mean looking durations were found to be longer for novel-sized objects than for familiar-sized objects. Thus, although infants in both age groups were able to discern the physical sizes of objects, only 12-month-olds could successfully discriminate between the familiar and novel sizes of everyday objects. Notably, 12-month-olds demonstrated knowledge of familiar size even though the test objects were out of their reach and, consequently, unamenable to manual exploration.