Spatial frequency analysis of block letters does not predict experimental confusions

Abstract

To test the generality of spatial frequency channels models of vision, matrices of similarities between spatial frequency compositions of letters of the alphabet were generated mathematically. Methods and assumptions were chosen to reflect probable neural underpinnings of spatial frequency analysis mechanisms. These similarity matrices were tested against experimentally produced confusion matrices. The similarity matrices predicted subjects' confusions poorly: the best predictions were made, not by any of the spatial frequency similarities, but by similarities between the original letter stimuli input to the spatial frequency analysis programs. Previously reported feature analytic models seem to better describe the confusion patterns. © 1978 Psychonomic Society, Inc.