Coglab Mental Rotation Summary

The experiment tries to show that people can not only create images but also mentally transform them. They present the subjects with two 3D line-drawing of random block shapes. The subjects are asked to decide if the two images are the same object by pressing two different keys on the keyboard. In some cases the two images are the same object with one rotated by some degree. In other cases the two images are mirror images that are similar but not identical. The mirror images are also rotated sometimes. The dependent variable is the reaction time. The independent variables are stimuli that have the same shapes vs. stimuli that have different shapes, and the degree of rotation. The control conditions are the multiple trials and the selection of only correct responses. The hypothesis is that if the reaction time is affected by the degree of rotation of the images, subjects perform the task by mental rotation of the drawings because it takes time to rotate the mental images just like real images. The result shows that the reaction time is indeed affected by the degree of rotation; therefore, it demonstrates the hypothesis that people can mentally rotate images. It takes more time for subjects to react when the degrees of rotation increase. There are some methodology problems in this experiment design. First, the block-shape 3D images are hard to identify even one at a time for some people and the test only takes correct answer into consideration. The repetition of the tests may cause fatigue to some subjects and the correct answers can be generated by random clicking of images. Second, the block-shape objects are not something that we can encounter in the real life so the subjects may have to take extra effort to analyze the images. Finally, the correct answer can be derived by ways other than mental rotation. For example, you can simply just find a starting point of the block-shape images and ‘walk through’ the images to see if the two images have the same ‘route’