Imaginary Completion of Color Sequence by Analogy as a Tool for Objective Assessment of Mental Imagery of Color

Object imagery, representing pictorial features, and spatial imagery, representing spatial relations and transformations, are two aspects of visual mental imagery distinguished in the literature. While spatial imagery is assessed primarily with performance tests that allow an objective assessment of mental images, object imagery is assessed mainly on the basis of subjective self-report on imagery vividness. Aiming to fill this methodological gap, we developed an experimental task for color imagery, allowing an objective assessment of imagery performance. We took as a basis the structure of the methodological “gold standard” for the studies of spatial imagery—the Shepard and Metzler mental rotation task. Its important features are parametrically specified levels of complexity, measurement of the accuracy and reaction time, and restricted options for verbalizing. Our missing-color task requires mental construction of the missing color by analogy. Two levels of difficulty of the task with color sequences within a single hue were used in a pilot study on a sample of 35 young adults. The results indicate that a number of participants (37% in our sample) are able to generate task-relevant and differentiated representations of color, although the proportion of such people in the population is presumably significantly smaller than the proportion of people who provide high subjective ratings of their mental images in tasks requiring imagination of colored objects and scenes from verbal description. A more detailed understanding of the population distribution of color imagery performance and of possible mechanisms behind it will require further research on larger samples, as well as developing additional control tasks.