Movement Imagery in Young and Congenitally Blind Children: Mental Practice without Visuo-spatial Information

Abstract

The study explored whether young children and congenitally totally blind children show mental practice effects for blind movements which cross the body midline. Experiment 1 tested blindfolded sighted children, with a mean age of 7 years and 11 months, on recall of a linear movement. Prior to recall, subjects either had to perform, or to imagine irrelevant (larger/smaller/same) movements. Irrelevant movements produced significant bias (CE/Constant Errors), whether carried out or imaged, although bias from imagined movements was smaller. The VE (variance/consistency) scores improved with (actual and mental) rehearsal. Articulatory suppression during delays had no effect. Experiment 2 used the same paradigm to test three groups of congenitally totally blind children with respective mean Mental Ages (MA) of 10 years and 7 months, 13 years and 7 months, and 16 years and 4 months, based on IO scores on the Williams Intelligence Test (1956) for visually handicapped children. Irrelevant movements during delays produced bias (CE) in recall, whether the movements were carried out or imagined, although bias was smaller in imagery conditions. The (CE) bias effects did not interact with MA. Mental Age interacted significantly with Delay Tasks in VE scores. The lowest MA group was less efficient (more variable) than the others, particularly in (actual and imagined) rehearsal. Articulatory suppression had no effect. The results suggest that young children can show mental practice effects in the absence of current visual cues, and that visuospatial imagery is not a necessary condition, because imagined movements also biased recall by the congenitally totally blind. It was argued that movement as well as cognitive factors can be involved in mental practice effects, and that the nature of mediation depends on the available information.