Although the absolute accuracy of the tilting angles was not of primary interest in the current
study, we found as an interesting side result that all age groups systematically underestimated the
tilting angles for the thin glasses, especially adults and when tilting without vision. A possible explanation
for this could be that adults took a more cognitive approach, whereas younger children relied
more on their (accurate) motor simulations. Schwartz and Black found similar effects and (referring to
Schwartz & Hegarty, 1996) argued that adults often choose their ‘‘head over their hands” and preferably
rely on their beliefs rather than on the results of their simulations. This interpretation would also
be in line with Kosslyn’s (1978, 1980) hypothesis of representational development and with his results
(Kosslyn, 1976) that 6-year-olds spontaneously fell back on imagery strategies more frequently than
older children and adults.