Fifty-two college-aged observers participated in an experiment assessing color memory via a PowerPoint '97 computer display program which varied one of the three dimensions of hue, saturation and lightness at a time. Consistent with previous research, errors were greater for the lightness conditions followed by saturation, and least for hue conditions Additionally, a signal detection analysis indicated that d-prime was greatest for the hue conditions, less for saturation and lowest for lightness conditions. There were also significant but unpredicted differences in response criterion which may reflect task difficulty. Scores on the Vividness of Visual Imagery Questionnaire (Marks, 1973) were, in general, not correlated with performance on these color memory tasks, inconsistent with previous research. The role of complexity of neuronal circuitry, the significance for opponent-process, trichromatic and retinex color vision theories and the relationship to Sokolov's model of color memory were discussed. Also, it was concluded that investigators of color memory using a computer display are well-advised to calibrate the monitor with a colorimeter because the internal computer units may be unreliable indexes of changes in hue, saturation and lightness. / Ph. D.

Mental images are unique mental representations and the depictive view in the imagery debate states that mental images have similar spatial structures as their corresponding external object. The propositional view, however, contends that beliefs about the external world influence a mental image – also known as the cognitive penetrability theory –, therefore mental images cannot be described in visual terms. People with self-described aphantasia, those considered lacking visual mental images, offer a new opportunity to approach this issue. The current study employed the mental rotation task (MRT), where a three-dimensional object needs to be mentally aligned with another one that is rotated to a different angular position. To test the effects of beliefs on mental images, different instruction conditions were used on the MRT. Twenty-seven participants (21 females, mean age 47 years) with self-described aphantasia completed an online experiment, consisting of the MRT, the Object-Spatial Imagery Questionnaire (OSIQ), and the Vividness of Visual Imagery Questionnaire (VVIQ). While participants scored low on the VVIQ and higher on the spatial items than on the object items of the OSIQ, the key finding was that increasing reaction time with increasing angular disparity on the MRT was not influenced by different instruction types. This suggests that the theory of cognitive penetrability is not applicable on mental rotation in aphantasia, highlighting the importance to revise how mental images (or the lack of them) are understood and described.