Judgment of numerosity: Effects of symmetry and goodness in dot pattern arrays

Abstract

Studies of numerosity judgment characteristically use random dot arrays as targets. A few recent studies have shown concern for the role played by configural properties of the pattern array in the judgment of numerosity. The primary purpose of the present short report was to establish whether amount of whole symmetry and part symmetry in an array affects the accuracy of numerosity judgment. A subsidiary purpose was to explore the relationship between probability of correct judgment of numerosity and independent data on the immediate recallability of the same pattern arrays. Two hundred patterns with array sizes 1–11 and five amounts of whole and part symmetry were used. There were two clear findings. One, that the probability of correct numerosity judgment increases with amount of whole symmetry but not of part symmetry. Two, that such probability scores yield essentially zero correlations with two measures of pattern recallability and with a measure of pattern goodness. The findings are consistent with the arguments (a) that whole symmetry is rapidly abstracted at a very early stage and facilitates parallel processing of numerosity, and (b) that the numerosity of an array is assessed sooner than the spatial locations of the configuration per se can be encoded.