Mental Rotation

Mental Rotation

Mental rotation is the ability to rotate mental representations of two-dimensional and three-dimensional objects. The ability is somewhat localized to the right cerebral hemisphere, largely in the same areas as perception, and is associated with spatial processing and general intelligence but not verbal skills.

Mental rotation is the brain moving objects in order to understand what they are and where they belong. It has been studied to try to figure out how the mind recognizes objects in the environment. Researchers call these objects stimuli. A stimulus then would be any object or image seen in the person’s environment that has been altered in some way. Mental rotation then takes place for the person to figure out what the altered object is.

In a mental rotation test, the subject is asked to compare two 3D objects (or letters) and state if they are the same image or if they are mirror images (enantiomorphs). Commonly, the test will have pairs of images each rotated a specific amount of degrees (e.g. 0°, 60°, 120° or 180°). Some pairs will be the same image rotated, and others will be mirrored. The subject will be shown a set number of the pairs. The subject will be judged on how accurately and rapidly they can distinguish between the mirrored and non-mirrored pairs. The process involves fives stages: 1) Create a mental image of an object, 2) Rotate the object mentally until a comparison can be made, 3) Make the comparison, 4) Decide if the objects are the same or not, and 5) Report the decision.

Cognitive scientist Roger Shepard and neuroscientist Jacqueline Metzler are considered pioneers in the study of spatial relations and are credited with discovering the phenomenon in 1971. Their research showed that the reaction time for participants to decide if a pair of items matched or not was linearly proportional to the angle of rotation from the original position. That is, the more an object has been rotated from the original, the longer it takes to determine if it is the same object or an enantiomorph. Shortly afterwards, a study demonstrated that a pair of mental transformations, size scaling and rotation, produced additive effects on reaction time, consistent with serial processing of these transformations.

In the following decade further research proposed the concept of a ‘Mental Imagery’ facility. Additionally, research discovered that it does not matter on which axis an object is rotated, but rather the degree to which it is rotated that has the most significant effect on response time. So rotations within the depth plane (i.e., 2D rotations) and rotations in depth (3D rotations) behave similarly. Thus, the matching requires more time as the amount of depth rotation increases, just as for within the depth plane.

In subsequent research, it has been found that response times increase for degraded stimuli and can decrease when participants are allowed to practice mentally rotating imagery. This research has been instrumental in showing how people use mental representations to navigate their environments. Also, males tend to be slightly faster in mental rotation tasks than females. The ability to rotate mentally (measured in terms of decline in response time) peaks in young adulthood, and declines thereafter.

Other recent research has centered on whether there might be multiple neural systems for the rotation of mental imagery. A 1987 study found that participants presented with line drawings of hands (rather than Shepard and Metzler-like 3D blocks) showed embodiment effects and were slower to rotate hand stimuli in directions that were incompatible with the way human wrist and arm joints move. This finding suggested that the rotation of mental imagery was underlain by multiple neural systems: that is, (at least) a motoric/tactile one as well as a visual one. In a similar vein a 2006 study found that adding a cylindric ‘head’ to Shepard and Metzler line drawings of 3D objects can create facilitation and inhibition effects as compared to standard Metzler-like stimuli, further suggesting that these neural systems rely on embodied cognition (the theory that the nature of the human mind is largely determined by the form of the human body).

Physical objects that we imagine rotating in everyday life have many properties such as textures, shapes, and colors. A study at the UC, Santa Barbara was conducted to specifically test the extent to which visual information, such as color, is represented during mental rotation. This study used several methods such as reaction time studies, verbal protocol analysis, and eye tracking. In the initial reaction time experiments, those with poor rotational ability were affected by the colors of the image, whereas those with good rotational ability were not. Overall, those with poor ability were faster and more accurate identifying images that were consistently colored. The verbal protocol analysis showed that the subjects with low spatial ability mentioned color in their mental rotation tasks more often than participants with high spatial ability. One thing that can be shown through this experiment is that those with higher rotational ability will be less likely to represent color in their mental rotation. Poor rotators will be more likely to represent color in their mental rotation using piecemeal strategies.

Research on how athleticism and artistic ability affect mental rotation in 2012 showed that people who were athletes or musicians had faster reaction times than people who were not. Students who were focused on sports did much better on a mental rotation test than those who were math or education majors Also it was found that the male athletes in the experiment were faster than females, but male and female musicians had no significant reaction time change.

Another experiment took undergraduate college students and tested them with the mental rotation test before any sport training, and then again afterward. The participants were trained in two different sports to see if this would help their spatial awareness. It was found that the participants did better on the mental rotation test after they had trained in the sports, than they did before the training. There are ways to train your spatial awareness. This experiment brought to the research that if people could find ways to train their mental rotation skills they could perform better in high context activities with greater ease.

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