Representation of object similarity in human vision: psychophysics and a computational model

We report results from perceptual judgment, delayed matching to sample and long-term memory recall experiments, which indicate that the human visual system can support metrically veridical representations of similarities among 3D objects. In all the experiments, animal-like computer-rendered stimuli formed regular planar configurations in a common 70-dimensional parameter space. These configurations were fully recovered by multidimensional scaling from proximity tables derived from the subject data. We show that such faithful representation of similarity is possible if shapes are encoded by their similarities to a number of reference (prototypical) shapes, as in the computational model that accompanies the psychophysical data.