Poster #163 - Real Objects and Visual-Manual Exploration Enhance Infants’ Understanding of Object Size

• In Event: 2-110 - Poster Session 07
  In Poster Session: PS 07 Section - Perceptual, Sensory, Motor

Integrative Statement

Previous research has shown that infants can successfully distinguish different sizes (e.g. Granrud 2006; Libertus et al.; 2013, Yonas et al., 1982). However, it remains an open question when and how infants learn the true size of objects. In the present study, we investigated when infants start to discriminate the true size of an object from novel sizes. We also examined how stimulus format (real objects vs. photographs) and the possibility to visually and manually explore objects influence infants’ visual responses.

A total of 139 7- and 12-month-old infants were presented with highly familiar objects as real objects or photographs (stimulus format). All stimuli were shown in their true size and in novel sizes (50% bigger or smaller than the true size). In a preferential looking paradigm, objects were presented simultaneously in pairs. Moreover, all stimuli were presented in a visual only condition for 10s and in a visual-manual condition for 20s per trial. For each exploration condition (visual / visual-manual), we conducted an analysis of variance with size, stimulus format and age as independent variables and looking times as the dependent variable.

All reported results are preliminary. In the visual condition, analysis of a significant age x size interaction, F(1,135) = 53.63, p ≤ .001, ηp2= .28, showed that 12-month-olds looked longer at the novel compared to the true sizes for both real objects and photographs, F(1,67) = 65.78, p ≤ .001, ηp2= .50; whereas, for the 7-month-olds, looking durations towards different-sized stimuli did not differ, F(1,70) = .22, p =639. In the visual-manual condition, analysis of a significant size x stimulus format, F(1,135) = 9.26, p = .003, ηp2= .06, showed that the preference for the novel sizes was stronger for the real objects compared to the photographs. A significant age x size interaction, F(1,135) = 20.17, p ≤ .001, ηp2= .13, revealed that the 12-month-olds looked longer at the novel compared to the true sizes, F(1,67) = 70,17, p ≤ .001, ηp2= .51, but the 7-month-olds did not, F(1,70) = 1.10; p =.297.

Taken together, our results show that infants can discriminate novel from familiar sizes and this ability is strongest for older infants (12- vs. 7-months-olds), for real objects (vs. photos) and when manual exploration is possible (vs. not). These results suggest that direct interactions with real objects facilitate children’s understanding of object size in ways beyond what is enabled by visual exploration alone or by pictures, which of course do not afford interactions. These results lend credence to the view that perception is an active process related to actions and the potential for actions and that these factors are critical in development.

Authors

• Özlem Sensoy, Department of Developmental Psychology, Justus-Liebig-University Giessen
  Presenting Author

• Jody C. Culham, Department of Psychology and Brain and Mind Institute, The University of Western Ontario, London
  Non-Presenting Author

• Gudrun Schwarzer, Department of Developmental Psychology, Justus-Liebig-University Giessen
  Non-Presenting Author