Color discrimination and luminance

This experiment studied the relation between luminance level and color discrimination at 570 millimicrons. A variety ofstimuli whose luminances varied from .1 to 100 ft-L were viewed against a variety of surrounds. 1t was found that color discrimination ability was a joint function of the luminance level of the stimulus and the ratio of the luminance of the stimulus to that of the surround.     

A note on luminance control in tachistoscopes

Procedures are described for measuring tachistoscopic luminance levels for brief light flashes and over longer intervals. Stability of luminance levels is discussed for both conditions.     

Visual movement perception: A comparison of sensitivity to vertical and horizontal movement

A psychophysical model that provides separate measures of judgmental standards and sensitivity is utilized to compare an O’s visual sensitivity for vertical and horizontal movement. The analysis indicates no consistent difference in sensitivity; those asymmetries that do exist simply appear to be due to idiosyncratic judgmental standards.     

The cognitive basis of the comprehension and production of relational terminology

The comprehension of big, little, and same number and the productio of relational terminology was assessed in 168 preschool children. Stimuli were used which varied the relationships of length, number, and density. Language comprehension and production were related to the complexity of cognitive operations required by the task. Specifically, comprehension was easier in the situations in which length and number were positively correlated than when length provided no cue to number. Comprehension was most difficult when length and number were negatively correlated. There was asymmetry in language comprehension such that the positive term big, was comprehended earlier than little in some tasks; there was also asymmetry in production in that the child was more likely to use language related to the positive pole than to the negative pole. These data were interpreted as providing support for theories of the cognitive basis of language acquisition.     

Sex differences in retention of verbal and spatial characteristics of stimuli

Males and females from Grades 3, 6, and college viewed sets of five or seven letters in a 4 × 4 matrix, and remembered either (a) names of the letters, (b) positions of the letters within the matrix, or (c) both letters and positions. At all grade levels females remembered letters more accurately than positions, while males remembered letters and positions equally well. However, there was also evidence that verbal and spatial information was processed independently by both males and females. Results are discussed in terms of neurological development and sex differences in specific abilities.