The present research focuses on the different subjective experiences evoked by perceived and imagined matrices of letters of the alphabet. In three experiments adult subjects were asked to rate the vividness of a letter included in a matrix of letters which varied due to manipulations in colour, rotation and movement. Subjects were asked to observe (perceptual modality), draw and observe (drawing modality), retrieve (memory modality) or imagine (imagery modality) the matrices. For some manipulations of the critical letter (in particular, 45 degrees inclination and high contrast colour), the perceptual modality produced comparatively higher vividness ratings than the other two modalities. The perceptual effect of inclination was also duplicated with the memory modality group.
It is argued that different visual processes, either immediate and pre-attentive, or sequential and attentive, may be operating under voluntary control. Although visual imagery varies in some ways from immediate visual perception, the similarities found, between the drawing and imagery modalities, on the one hand, and the perceptual and memory modalities, on the other hand, suggest that they share some common underlying processes.