Abstract
In this study adults and children were tested on their ability to use highlight information to perceive whether an object is polished or rough. Variations in the micro-texture of a surface determines whether it can produce high-contrast specular reflections, i.e. while a highly polished surface on a silver spoon create specular or sharp reflections, the matte surface of cloth creates only diffuse reflections. In this study a photograph of a highly polished plastic egg shape containing a clear reflection of a bright window provided specular reflection information for surface texture. A second photograph of the shape was created using Photoshop and a Gaussian blur transformation to reduce contrast over the surface. By using fine sandpaper, a polished egg was also transformed into a tactual non-polished egg. Fifteen adults and fifteen preschool children between 35 to 70 months of age took part in the study. First, children were tested on their ability to make a cross modal match between a fur covered object and a wooden object of the same shape. In the experiment, participants were presented with each photograph and were asked to reach into a box and select by touch the one that matched the displayed picture. All adult participants chose the correct object on every trial when presented with the pictures of furry and non-furry objects and the highlighted and non-highlighted pictures. The children differentiated the textures of furry and non-furry objects (92% correct) better than highlighted and diffused objects (68% correct). Although the average performance of the children provided reliable evidence that they perceived that a photograph with high contrast specular reflections specified that a surface is smooth while a blurred image indicates that a surface is rough, several of the younger children performed at a chance level. The meaning of highlights may be learned at about the end of the second year.
Tenzin Tsamda'w work was supported by a grant from the University of Minnesota Center for Cognitive Sciences