Rotating objects in our mind's eye is a bit like doing it in the real world. For example, when asked to judge if one shape is a rotated version of another, the time it takes us to answer correlates with the angular discrepancy between the two shapes. It's as if we manipulate objects in our imagination, as we would turn real objects in our hands.
Now Gunnar Wiedenbauer and colleagues have investigated whether manual rotation training, using a joystick to rotate shapes on a screen, can improve participants' mental rotation skills. Past research has shown that people become much improved at mental rotation with practice, but this is thought to be due to their learning the different shape configurations, so that the task effectively becomes a test of memory rather than mental rotation. Indeed, after extensive practice, the usual correlation between rotated angle size and reaction time disappears.
Sixty-four participants performed two mental rotation tests in which they had to judge as fast as possible whether one shape was a rotated version of a second shape. In between the two tests, half the participants underwent manual rotation training, manipulating shapes on a screen with a joystick to match target shapes. Half the shapes in the second test were featured in the manual training, half were new.
The results were mixed. Participants who underwent the manual training did indeed perform more quickly in the second mental rotation test than the control subjects, but only for the shapes that were featured in the training. If the training really had improved mental rotation ability, the trained participants ought to have outperformed the control participants on all the shapes.
And yet, during the second test, the trained participants' extra-quick judgment time (for shapes that had featured in the training) still correlated with angular discrepancy. This suggests that for these shapes, the trained participants weren't just relying on memory - they really had improved their mental rotation ability. “It seems that mental rotation is a complex multilayer process that has to be further investigated”, the researchers said.
Wiedenbauer, G., Schmid, J. & Jansen-Osmann, P. (2007). Manual training of mental rotation. European Journal of Cognitive Psychology, 19, 17-36.