Variables of color, duration, frequency, presentation order, and sex in the estimation of dot frequency.

The estimation of number depends on the information as dot frequency, exposure conditions, order of presentation, and sensitivity of the observer to color. Ninety-six color-normal observers (age 17-27) equally divided by sex were assigned so that each one viewed 42 cards, each of which contained dots of one of three colors on one of two grounds at one of seven frequency levels. For any observer, cards were exposed for either .5 second or 1.0 second intervals and in either ascending or descending order. The ANOVA indicated a significant effect for the following variables: dot frequency, dot color, and exposure time. Estimates increased with dot number on the several displays. Yellow-red (YR) dots were slightly overestimated. Yellow-green (YG) and gray dots were not. The briefer exposure yielded an underestimation and the longer an overestimation. Interpolated intervals are given for correct estimates.