Abstract
Most developmental studies consistently show that only infants aged at least 6–7 months and older can perceptually integrate disconnected image fragments and complete missing structures based solely on pictorial information (e.g. Bertenthal, 1980). Here, we show an example of early emergence of visual completion using purely static two-dimensional pictorial information. We created mixed polarity Kanizsa figures that are either consistent or inconsistent with perception of an illusory transparent surface. Both configurations have the same local geometry and also contain very similar contrast polarity variations across the four inducers. The perception of transparency is manipulated by the distribution of contrast polarity variations in each configuration.
A total of 48 Japanese infants aged 3–4 and 5–6 months participated in the preferential looking study.
In the Experiment 1, we presented either the transparent or the non-transparent Kanizsa figure side by side with their respective control configurations that consisted of identical but rotated elements. We found that both 3–4 and 5–6 significantly preferred the transparent Kanizsa figure to its rotated control. There was no such preference between the non-transparent Kanizsa figure and its rotated control configuration.
In the Experiment 2, we directly compared infants' preference between the two types of Kaniza figures. As the two types of the Kanizsa figures slightly differed in terms of the local contrast intensity, we presented the rotated version of these figures side by side as a control condition. We found that both 3–4 and 5–6 months significantly preferred the Kanizsa figure that induces perception of illusory transparent surface than the one which does not. No preference was observed in the control condition. The results from two experiments clearly demonstrate that both 3–4 and 5–6 months perceived the illusory transparent surface in the mixed polarity Kanizsa figure.
This study was supported by Kakigi's group of RISTEX, the Japan Science and Technology Agency, by a Grant-in-Aid for scientific research (18000090, 196068) from the JSPS.