Mental Rotation Of Images

Abstract

The idea of mental imagery has always been a controversial subject in the field of psychology. Many psychologists have argued that such a concept is impossible to measure because it can not be directly observed. Though they are right about this, it is not impossible to measure how quickly mental rotations of images are processed in our brains. Subjects in this experiment were presented two shapes simultaneously, via computer screen, and asked to make judgement, as quickly as possible, as to whether the two shapes presented were the same or mirror images. Two different shapes were used in this experiment, each given as often as the other. During each trial one shape remained stationary and the other was rotated with varying amounts of 0, 60, 120, and 180 degrees. As the angle of rotation increased reaction times were calculated to see if this had any baring on the speed of the reaction. As predicted, reaction times increased along with angular disparity.













Rotation of Mental Images: Measured by Reaction Times
There are a limited number of ways to discover and understand how the human mind works and reacts to things. One can not sit and directly observe the brain and eye working together (James, Schneider & Rodgers, 1994). The concept behind mental rotation of images tries to do this by measuring reaction times as the angular disparity of an object increases. Thus, demonstrating the time it takes for the eye and brain to make a connection when presented with a stimulus. Though our experiment was solely limited to calculating reaction times to mental rotations of images, Wohlschlager and Wohlschlager (1998) took this concept one step further to see if mental object rotation and manual object rotation shared a common thought process in our brain.
Wohlschlager & Wohlschlager (1998) based their ideas for this study on a theory, most impressively demonstrated by Cooper (1976), stating that the resemblance of mental rotation to external physical rotation, calls for a mental process that mimics external physical rotation. However, it is pointed out that there is a principal difference between motion perception and mental rotation. Whereas motion perception is a rather automatic process, mental rotation is strategic and shares some characteristics with voluntary actions (Wohlschlager & Wohlschlager, 1998).
In conducting their experiment Wohlschlager & Wohlschlager (1998) used 66 right-handed psychology students who took part in this experiment to fulfill their course requirement. Of the 66 students 30 took part in the mental rotation condition and 30 in the manual rotation condition.
As expected, findings showed that there was in fact a strong relationship between the reaction times of the mental and manual rotations. As the angular disparity of both the mental and manual rotations increased so did reaction times. In almost all cases manual and mental reaction times matched each other. It was also observed by Wohlschlager & Wohlschlager (1998), that manual object rotation did not always follow the shortest path. Findings showed that in some trials students rotated images the longer way around. Thus, it was concluded that mental processes also rotate things the long way around, since reaction times did not differ much between the two groups, ultimately supporting their original hypothesis.
Desrocher, Smith & Taylor (1995) conducted a similar experiment with intentions of measuring reaction times. Only in this experiment the independent variable was not mental vs. manual rotation, but gender. They were interested in seeing if gender differences played a role in regard to reaction times, when presented with either a letter stimuli or picture stimuli. It has been noted that up to the present time, there have been no major findings that show any significant difference in the way men and woman process letter images. In tests, both men and woman performed equally well (Desrocher, smith & Taylor, 1995). However, in several experiments conducted measuring reaction times

when presented with a picture stimulus, men have been said to out perform woman in almost all cases. Overall, when comparing the reaction times of pictures to letters, picture reaction times are said to be generally greater.
In conducting this experiment 20 right-handed subjects were used, 10 male and 10 female. Subjects participated in this study either to earn course credit, or for payment of ten dollars per hour.
Three things were concluded from this experiment. First, picture rotations