Size invariance in visual object priming of gray-scale images.

The strength of visual priming of briefly presented gray-scale pictures of real-world objects, measured by reaction times and errors in naming, was independent of whether the primed picture of the object was presented in the same size as or different size from the original picture. These findings replicate results on size invariance in shape recognition, which were obtained with line drawings, and extend them to the domain of gray-level images. Entry-level shape identification is based predominantly on scale-invariant representations incorporating orientation and depth discontinuities which are well captured by line drawings.