Abstract
Background: Several lines of evidence from adult psychophysics, brain imaging data, and honeybee's behavior have supported the notion that topological properties are the primitives of visual representation (Chen, 1982). However, the developmental origin of the sensitivity to topological properties in infancy has not been explored. Thus, the present study aims to explore 2- to 6- month old infants' visual sensitivity to topological versus geometric properties
Methods: The forced-choice novelty preference technique (FNP) was used to test infant's perceptual discriminability. Two discrimination tasks and one generalization task were adopted. A disk and a ring were used in the topologically different condition (but geometrically equivalent), while a disk and a triangle were used in the geometrically different condition (but topologically equivalent). In the generalization task, infants were first familiarized with a pair of identical disks, and then were tested with two novel figures in the test phase in which one was topologically different (a ring) and the other was geometrically different (a triangle).
Results: Our results showed that in the discrimination tasks, 2- to 6-mo-old infants could reliably discriminate figures based on topological difference, but were unable to discriminate figures based on geometric difference. In the generalization task, infants reliably looked more at the “ring” pattern in the test phase, suggesting that the ring appeared to be perceptually more “different” to the infants than the triangle. Further analysis on age versus novelty score revealed two distinct developmental trends. Infants seem to be readily sensitive to topological differences as young as 7 weeks old, while their ability to discriminate geometrical differences significantly improves between 12- and 26- weeks old. In conclusion, our finding suggested that the ability to process topological properties seems to be present and functioning very early in life.
This project was supported in part by Grant# NSC 98-2410-H-039-006 and in part by Internal Grant# CMU 98 – N2 – 20 to Dr. S. H. L. Chien.