MIRROR DRAWING - EFFECTS OF ENVIRONMENTAL-POLLUTION, TRIAL ORDER AND LATERALITY

The factor effects given in the title were investigated in a sample of 136 right-handed school children, with the time needed for tracing a simple acute-angled path as criterion. Optical feedback during the tri al was possible only by means of a vertical mirror, and the hand order of the measurements (RL vs. LR) was randomized. The raw performance d ata were logarithmically transformed and variance analyzed: the result ing ANOVA confirmed the existence of significant differences for every factor. In spite of using the data of right-handed children only, the means for the right hand were significantly higher (indicating a wors e performance) than for the left; and children living in an industrial ly contaminated environment had significantly lower means (attesting t o a quicker execution of the task) than children from a region with a relatively clean, i.e. less neurotoxin-polluted atmosphere. Trial orde r showed slower performances for the first measurements than for the s econd ones, with this effect being significantly more pronounced when the first attempt was done with the right hand. The implications of th is interaction are discussed in terms of hemispheric activation and ge neral learning effects.