Aging faces as viscal-elastic events: Implications for a theory of nonrigid shape perception.

Abstract

A theory for the perception of events is proposed using the concepts of transformational and structural invariants. This approach involves the application of a method of spatial coordinate transformation to characterize the remodeling of faces by growth. By construing growing faces to the viscal-elastic events, the perception of the relative age level faces in made amenable to the proposed event perception analysis. Shear and strain transformation are compared as alternative formulations of growth-produced changes in the shape of human profiles. Thes studies indicate that profiles transformed by strain elicit more reliable rank-order age judgments than those transformed by shear, although shear had a small significant effect. It is also shown that subjects are highly sensitive to small changes in strain, and that perceived identity of a shape is preserved under the strain transformation. The explanatory adequacy of the event perception theory of age information is compared to that of more traditional feature analytic theories.

Factors Influencing the Accuracy of Age Estimates of Unfamiliar Faces

“…This is consistent with previous research demonstrating the effects of similar transformations on apparent age (eg Pittenger and Shaw 1975;Mark and Todd 1983;Bruce et al 1991), although the effects of the strain transformation in our experiments were weaker than the results of previous research might have led us to expect. One reason for this is that in experiment 2 we used a between-subjects design, which may have been less sensitive to the effects of strain than the within-subjects designs typically used by previous researchers to investigate this phenomenon.…”

“…Through growth and ageing the face comes to occupy a larger part of the head, and the internal features (eyes, nose, and mouth) effectively move upwards on the head. During the past twenty years numerous studies have demonstrated that manipulations of the level of cardioidal strain applied to a face affect subjects' judgments of the age of the face (eg Pittenger and Shaw 1975;Pittenger et al 1979;Todd 1983, 1985;Bruce etal 1989). Faces appear older if the strain transformation is applied in one direction, and younger if it is applied in the opposite direction.…”

Visual information for object identity in apparent movement

“…As noted in the introduction, the affordance structure of an event is composed of a component that remains constant and a component that changes (Pittenger & Shaw, 1975). The transformable displays in this experiment contain geometric information which specifies a single object undergoing a certain change-the affordance structure of a certain unified event.…”

“…On the other hand, biomorphic transformations of nonrigid objects (such as growth, flexion, and locomotion) may require excursions into topology to locate their defining invariants (see Pittenger & Shaw, 1975 …”

“…E. J. Gibson (Note 2) has catalogued such ecologically valid shape transformations, which include translation, looming, perspective shift, and such biomorphic deformations as locomotion and growth. On this basis, Shaw has proposed (Pittenger & Shaw, 1975;Shaw & Wilson, in press) that every event is defined by its affordance structure, composed of a "structural invariant," the constants of the object or layout, and a "transformational invariant," the type of transformation or change the object undergoes. This suggests a framework in which to discuss object identity in apparent movement.…”