Abstract
To evaluate the role of attention, memory span, and visualization in the performance of additions carried out mentally, two blocks of mental additions differing in difficulty were presented to 18 women and 18 men who recorded after the first block the strategy used for solution. The 24 subjects who did not spontaneously use a visual strategy (mentally putting digits into columns) were induced to adopt it for the second block of additions. Previously, the subjects' processing of visual images, memory for digit span, and resistance to distraction were assessed using imagery tasks, a Digit-span test, and the Stroop Color-Word test. Analysis showed that in the execution of mental addition use of different strategies did not influence significantly the performance on the easier items, whereas for more difficult calculations a nonvisual strategy appeared more effective. Subjects who had lower scores on visualization did worse if they spontaneously used a ‘putting-into-columns’ strategy or if induced to change a strategy and adopt a visual one.