Letter Similarity Data Set Archive

Gilmore, Hersh, Caramazza, & Griffin, 1979

Gilmore, G. C., Hersh, H., Caramazza, A., & Griffin, J. (1979). Multidimensional letter similarity derived from recognition errors. Perception & Psychophysics, 25, 425-431.


Experimenters collected a confusion matrix on briefly presented stimuli with open-ended verbal response.


Stimuli were presented from 10-70 ms, adjusted for each individual, with a mean of 33 ms across participants, so that the proportion of correct responses was about 50%. Stimuli subtended 14' x 20' at 64 cm, in green against a dark background.


Stimuli were described as filling a 5x7 dot-matrix, and were presented in Figure 1, but too small to reproduce legibly. Below is a reproduction of those letters in a 5x7 dot pattern identical to those found in Figure 1, although both the aspect ratio and the relative size of the filled pixels may be different from the original stimuli.


The original confusion matrix can be found here. Authors also presented a symmetric similarity matrix with corresponding response bias according to a Choice Model, based on the original confusions, and a Euclidean distance matrix based on an Multi-dimensional Scaling (MDS) solution. Data were entered with OCR software, and little or no effort was made to verify correctness.

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