Mental rotation


Mental rotation is the ability to rotate mental representations of two-dimensional and three-dimensional objects as it is related to the visual representation of such rotation within the human mind. There is a relationship between areas of the brain associated with perception and mental rotation. There could also be a relationship between the cognitive rate of spatial processing, general intelligence and mental rotation.
Mental rotation can be described as the brain moving objects in order to help understand what they are and where they belong. Mental rotation has been studied to try to figure out how the mind recognizes objects in their environment. Researchers generally call such objects stimuli. Mental rotation is one cognitive function for the person to figure out what the altered object is.
Mental rotation can be separated into the following cognitive stages:
  1. Create a mental image of an object from all directions.
  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.
  5. Report the decision.

    Assessment

In a mental rotation test, the participant compares two 3D objects, often rotated in some axis, and states if they are the same image or if they are mirror images. Commonly, the test will have pairs of images each rotated a specific number of degrees. A set number of pairs will be split between being the same image rotated, while others are mirrored. The researcher judges the participant on how accurately and rapidly they can distinguish between the mirrored and non-mirrored pairs.

Notable research

Shepard and Metzler (1971)

and Jacqueline Metzler were some of the first to research the phenomenon. Their experiment specifically tested mental rotation on three-dimensional objects. Each subject was presented with multiple pairs of three-dimensional, asymmetrical lined or cubed objects. The experiment was designed to measure how long it would take each subject to determine whether the pair of objects were indeed the same object or two different objects. Their research showed that the reaction time for participants to decide if the 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 an individual to determine if the two images are of the same object or enantiomorphs.

Vandenberg and Kuse (1978)

In 1978, Steven G. Vandenberg and Allan R. Kuse developed a test to assess mental rotation abilities that was based on Shepard and Metzler's original study. The Mental Rotations Test was constructed using India ink drawings. Each stimulus was a two-dimensional image of a three-dimensional object drawn by a computer. The image was then displayed on an oscilloscope. Each image was then shown at different orientations rotated around the vertical axis. Following the basic ideas of Shepard and Metzler's experiment, this study found a significant difference in the mental rotation scores between men and women, with men performing better. Correlations with other measures showed strong association with tests of spatial visualization and no association with verbal ability.

Neural activity

In 1999, a study was conducted to find out which part of the brain is activated during mental rotation. Seven volunteers between the ages of twenty-nine to sixty-six participated in this experiment. For the study, the subjects were shown eight characters 4 times each and the subjects had to decide if the character was in its normal configuration or if it was the mirror image. During this task, a PET scan was performed and revealed activation in the right posterior parietal lobe.
Functional magnetic resonance imaging studies of brain activation during mental rotation reveal consistent increased activation of the parietal lobe, specifically the inter-parietal sulcus, that is dependent on the difficulty of the task. In general, the larger the angle of rotation, the more brain activity associated with the task. This increased brain activation is accompanied by longer times to complete the rotation task and higher error rates. Researchers have argued that the increased brain activation, increased time, and increased error rates indicate that task difficulty is proportional to the angle of rotation.

Color

Physical objects that people imagine rotating in everyday life have many properties, such as textures, shapes, and colors. A study at the University of California 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.

Effect on athleticism and artistic ability

Research on how athleticism and artistic ability affect mental rotation has also been done. Pietsch, S., & Jansen, P. showed that people who were athletes or musicians had faster reaction times than people who were not. They tested this by splitting people from the age of 18 and higher into three groups. Group 1 was students who were studying math, sports students and education students. It was found that through the mental rotation test students who were focused on sports did much better 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 showed no significant difference in reaction time.
Moreau, D., Clerc, et al. also investigated if athletes were more spatially aware than non-athletes. This 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.
A study investigated the effect of mental rotation on postural stability. Participants performed a MR task involving either foot stimuli, hand stimuli, or non-body stimuli and then had to balance on one foot. The results suggested that MR tasks involving foot stimuli were more effective at improving balance than hand or car stimuli, even after 60 minutes.
Researchers studied the difference in mental rotation ability between gymnasts, handball, and soccer players with both in-depth and in-plane rotations. Results suggested that athletes were better at performing mental rotation tasks that were more closely related to their sport of expertise.
There is a correlation in mental rotation and motor ability in children, and this connection is especially strong in boys ages 7–8. Children were known for having very connected motor and cognitive processes, and the study showed that this overlap is influenced by motor ability.
A mental rotation test was carried out on gymnasts, orienteers, runners, and non athletes. Results showed that non athletes were greatly outperformed by gymnasts and orienteers, but not runners. Gymnasts did not outperform orienteers.

Sex

Some studies have shown that there is a difference between male and female in mental rotation tasks. In order to explain this difference, brain activation during a mental rotation task was studied. In 2012, a study have been done on people that graduated in sciences or in liberal arts. Males and females were asked to execute a mental rotation task, and their brain activity was recorded with an fMRI. The researchers found a difference of brain activation: males present a stronger activity in the area of the brain used in a mental rotation task.
A study from 2008 suggested that differences may occur early during development. The experiment was done on 3- to 4-month-old infants using a 2D mental rotation task. They used a preference apparatus that consists of observing during how much time the infant is looking at the stimulus. They started by familiarizing the participants with the number "1" and its rotations. Then they showed them a picture of a "1" rotated and its mirror image. The study showed that males are more interested by the mirror image. Females are equally interested by the "1" rotated and its mirror image. According to the study, this may mean that males and females, at least when infants, process mental rotation differently.
Another study from 2015 was focused on women and their abilities in a mental rotation task and in an emotion recognition task. In this experiment, they induced a feeling or a situation in which women feel more powerful or less powerful. They were able to conclude that women in a situation of power are better in a mental rotation task than other women.
Studying differences between male and female brains can have interesting applications. For example, it could help in the understanding of the autism spectrum disorders. One of the theories concerning autism is the EMB. This theory considers that autist have an "extreme male brain". In a study from 2015, researchers confirmed that there is a difference between male and female in mental rotation task : Males are more successful. Then they highlighted the fact that autists do not have this "male performance" in a mental rotation task. They conclude their study by "autistic people do not have an extreme version of a male cognitive profile as proposed by the EMB theory".
Some recent studies suggest that difference between Mental rotation cognition task are a consequence of procedure and artificiality of the stimuli. A 2017 study leveraged photographs and three-dimensional models, evaluating multiple different approaches and stimuli. Results show that changing the stimuli can eliminate any male advantages found from the Vandenberg and Kuse test.

Current research directions

There may be relationships between competent bodily movement and the speed with which individuals can perform mental rotation. Researchers found children who trained with mental rotation tasks had improved strategy skills after practicing. Follow-ups studies will compare the differences in the brain among the attempts to discover effects on other tasks and the brain. People use many different strategies to complete tasks; psychologists will study participants who use specific cognitive skills to compare competency and reaction times. Others will continue to examine the differences in competency of mental rotation based on the objects being rotated. Participants' identification with the object could hinder or help their mental rotation abilities across gender and ages to support the earlier claim that males have faster reaction times. Psychologists will continue to test similarities between mental rotation and physical rotation, examining the difference in reaction times and relevance to environmental implications.