The precision of visual memory for a complex contour shape measured by a freehand drawing task

Contour information is an important source for object perception and memory. Three experiments examined the precision of visual short-term memory for complex contour shapes. All used a new procedure that assessed recall memory for holistic information in complex contour shapes: Participants studied, then reproduced (without cues), a contoured shape by freehand drawing. In Experiment 1 memory precision was measured by comparing Fourier descriptors for studied and reproduced contours. Results indicated survival of lower (holistic) frequency information (i.e., ⩽5 cycles/perimeter) and loss of higher (detail) frequency information. Secondary tasks placed demands on either verbal memory (Experiment 2) or visual spatial memory (Experiment 3). Neither secondary task interfered with recall of complex contour shapes, suggesting that the memory system maintaining holistic shape information was independent of both the verbal memory system and the visual spatial memory subsystem of visual short-term memory. The nature of memory for complex contour shape is discussed.

► Memory for the holistic information of complex contour shape was examined.
► Freehand drawing recall and Fourier descriptors were used to estimate the memory.
► Lower but not higher frequency information (⩽5 cycles/perimeter) survived in memory.
► Verbal and visuospatial memory loads did not interfere with the memory performance.