Each of these .mat files contains 4 variables:
* n = number of objects 
* labs = string array of labels for the objects 
* s = n x n symmetric matrix of normalised pairwise similarities between the objects 
* d = n x n symmetric matrix of normalised pairwise proximities between the objects 
* From research described in Shepard, R. N., Kilpatrick, D. W., & Cunningham, J. P. (1975). The internal representation of numbers. Cognitive Psychology, 7, 82-138, with thanks to Josh Tenenbaum. 
* Human judgments of the numbers 0-9 [abstractnumbers.mat <abstractnum.mat>] 
* From research reported in Kuennapas, T., & Janson, A-J. (1969). Multidimensional Similarity of Letters. Perceptual and Motor Skills, 28, 3-12. 
* Auditory confusions of 25 letters (all excluding 'o') and the numbers 0-9 [<auditory.mat>] 
* From research reported in Roethlisberger, F. J., & Dickson, W. J. (1939). Management and the worker. Cambridge, MA: Harvard University Press. 
* A sociologist's judgment of the relationships between 14 bank wiring workers [<bankwiring.mat>] 
* From research reported in Ekman, G. (1954). Dimensions of color vision. The Journal of Psychology, 38, 467-474. 
* Human judgments of 14 colours, specified by their wavelengths [<colours.mat>] 
* From raw data presented in Romesburg, H. C. (1984). Cluster analysis for researchers. Belmont, CA: Lifetime Learning Publications. 
* Voting patterns of 14 members of congress on environmental bills [<congress.mat>] 
* From research reported in Glushko, R. J. (1975). Pattern goodness and redundancy revisited: Multidimensional scaling and hierarchical cluster analysis. Perception & Psychophysics, 17(2), 158-162. 
* Human judgments of 17 dot patterns [<dotpatterns.mat>] 
* From research reported in Huba, G. L., Wingard, J. A., & Bentler, P. M. (1981). A comparison of two latent variable causal models for adolescent drug use. Journal of Personality and Social Psychology, 40(1), 180-193. 
* Reported adolescent use of 13 drug types [<druguse.mat>] 
* From research reported in Gati, I., & Tversky, A. (1982). Representations of qualitative and quantitative dimensions. Journal of Experimental Psychology: Human Perception and Performance, 8(2), 325-340. 
* Human judgments of 16 drawings of flowerpots [<flowerpots.mat>] 
* From research reported in Tversky, A., & Hutchinson, J. W. (1986). Nearest Neighbor Analysis of Psychological Spaces. Psychological Review, 93(1), 3-22. 
* Human judgments of 21 fruits [<fruits.mat>] 
* From research reported in Gibson, E. J., Osser, H., Schiff, W., & Smith, J. (1963). An analysis of critical features of letters, tested by a confusion matrix. Cooperative Research Project No. 639, U.S. Office of Education. 
* Kindergarten children's judgment of perceptual similarity of the 26 capital letters [<letters.mat>] 
* From research reported in Rothkopf, E. Z. (1957). A measure of stimulus similarity and errors in some paired-associate learning tasks. Journal of Experimental Psychology, 53, 94-101. 
* Confusion of Morse code numerals [<morsenumbers.mat>] 
* Confusion of Morse code numerals and letters [<morseall.mat>] 
* From research reported in Miller, G. A., & Nicely, P. E. (1955). An analysis of perceptual confusions among some English consonants. Journal of the Acoustical Society of America, 27, 338-352. 
* Auditory confusion of 16 consonant phonemes [<phonemes.mat>] 
* From research reported in Johnson, E. J., & Tversky, A. (1984). Representations of Perceptions of Risks. Journal of Experimental Psychology: General, 113(1), 55-70. 
* Human judgments of 18 risks [<risks.mat>] 
* From research described in Chapter 15 of Borg, I., & Lingoes, J. (1987). Multidimensional similarity structure analysis. New York: Springer Verlag. 
* Human judgments of 16 rectangles [<rectangles.mat>] 
The following .mat files also contain a variable sigma_emp, which gives an empirical estimate of the precision of the similarity and proximity data: 
* From research reported in Robinson, J. P., & Hefner, R (1967). Multidimensional Differences in Public and Academic Perceptions of Nations. Journal of Personality and Social Psychology, 7(3), 251-259. 
* Human judgments (in 1967) of 17 countries [<country_robinsonhefner.mat>] 
* From research reported in Kruschke, J. K. (1993). Human category learning: Implications for backpropagation models. Connection Science, 5, 3-36. 
* Human judgments of 8 rectangles with interior line segments [rectangles_kruschke.mat <rectangle_kruschke.mat>] 
* From research reported in Rosenberg, S., & Kim, M. P. (1975). The Method of Sorting as a Data-Generating Procedure in Multivariate Research. Multivariate Behavioral Research, 10, 489-502. 
* Human judgments of 15 kinship terms [kinship_rosenbergkim.mat <kinship_kimrosenberg.mat>] 
* From research reported in Romney, A. K., Brewer, D. D., & Batchelder, W. H. (1993). Predicting Clustering from Semantic Structure. Psychological Science, 4(1), 28-34, with thanks to Devon Brewer. 
* Human judgments of 21 bird names [<birds_romney.mat>] 
* Human judgments of 21 clothing names [<clothing_romney.mat>] 
* Human judgments of 21 different clothing names [<clothing2_romney.mat>] 
* Human judgments of 21 fish names [<fish_romney.mat>] 
* Human judgments of 21 fruit names [<fruit_romney.mat>] 
* Human judgments of 21 different fruit names [<fruit2_romney.mat>] 
* Human judgments of 21 furniture names [<furniture_romney.mat>] 
* Human judgments of 21 different furniture names [<furniture2_romney.mat>] 
* Human judgments of 21 semantically unrelated words [<nonsense_romney.mat>] 
* Human judgments of 21 sport names [<sport_romney.mat>] 
* Human judgments of 21 tool names [<tools_romney.mat>] 
* Human judgments of 21 toy names [<toys_romney.mat>] 
* Human judgments of 21 vegetable names [<vegetables_romney.mat>] 
* Human judgments of 21 different vegetable names [<vegetables2_romney.mat>] 
* Human judgments of 21 vehicle names [<vehicles_romney.mat>] 
* Human judgments of 21 different vehicle names [<vehicles2_romney.mat>] 
* Human judgments of 21 weapon names [<weapons_romney.mat>] 
* Human judgments of 21 different weapon names [<weapons2_romney.mat>] 
* Mark Steyvers kindly provided the following data sets, and I have yet to chase up references: 
* Human judgments of 9 lines of different lengths [<lines_cohen.mat>] 
* Human judgments of 60 faces [<faces_busey.mat>] 
* Human judgments of 7 'morphed' faces [<faces_steyvers.mat>] 
* Human judgments of 9 shapes varying in size and angle [<sizeangle_treat.mat>] 
* Human judgments of 24 bodies varying in "affect and body size" [<bodies_viken.mat>] 
* From research reported in Heaps, C., & Handel, S. (1999). Similarity and Features of Natural Textures. Journal of Experimental Psychology: Human Perception and Performance, 25(2), 299-320. 
* Human judgments of 30 Brodatz textures [<texturebrodatz_heaps.mat>] 
* Human judgments of 24 MIT textures [<texturemit_heaps.mat>] 
* From the research described in Navarro, D.J., & Lee, M.D. (submitted). Common and distinctive features in stimulus representation: A modified version of the contrast model. Manuscript submitted for publication. 
* Human judgments of 10 cartoon faces [<cartoonfaces.mat>] 
* Human forced-choice judgments of 16 countries in a similarity condition [<countriessim.mat>] and a dissimilarity condition [<countriesdis.mat>] 
* From (as yet) unreported research in my lab 
* Human judgments of 21 animals (presented as pictures on a 5 point scale) [<animalpictures5.mat>] 
* Human judgments of 21 animals (presented as pictures on an 11 point scale) [<animalpictures11.mat>] 
* Human judgments of 21 animals (presented as words on a 5 point scale) [<animalnames5.mat>] 
* Human judgments of 21 animals (presented as words on an 11 point scale) [<animalnames11.mat>] 
* Human judgments of 25 faces (5 point scale) [<faces5.mat>] 
* Human judgments of 25 faces (11 point scale) [<faces11.mat>] 
* Here are two bitmap files with the face stimuli [<faces.bmp>, <faces2.bmp>]