Mental Rotation Task

Aim
To study the effect of angle of rotation on reaction time.
Introduction
Mental rotation is the ability to rotate mental representations of two-
dimensional and three-dimensional objects within the human mind. The mechanism behind
mental rotation involves a cognitive operation where a mental image is formed and rotated into a
different orientation in space. This process requires cognitive manipulation and spatial
transformation of two-dimensional or three-dimensional objects. Two main paradigms are
distinguished: perspective tasks involve determining how an object would appear from a
different viewpoint, while comparison tasks focus on identifying if pairs of visual stimuli,
presented from different angles, are identical or mirror images. The process of mental rotation
includes creating a mental image of an object from all directions, mentally rotating the object
until a comparison can be made, making the comparison, deciding if the objects are the same or
not, and reporting the decision. Studies have shown that mental rotation tasks engage areas of the
brain associated with perception and spatial processing, highlighting the intricate cognitive
processes involved in mental rotation.
The brain first perceives and encodes the visual features of the object or stimulus that
needs to be rotated. Mental rotation tasks consistently activate bilateral superior parietal lobes,
which are part of the visual-spatial network (VSN). This suggests the VSN is heavily involved in
the spatial processing and transformation required for mental rotation. The brain recognizes the
object and determines its current orientation with engagement of motor cortex and premotor
areas. Studies have shown increased activation in the primary motor cortex (M1) and premotor
cortex during mental rotation tasks. This indicates the brain may be simulating or preparing
motor movements as part of the mental rotation process. Mental rotation of the stimulus is the
next step where the brain mentally rotates the internal representation of the object, often in a
piecemeal fashion by rotating different parts sequentially. The lateral occipital cortex (LOC),
which is associated with object recognition, also shows greater activation during mental rotation
compared to non-rotation conditions. This likely reflects the encoding and manipulation of the
object representation.
During mental rotation tasks, the brain engages in comparing the rotated mental
representation with the target object to determine if they align or are mirror images. This process
involves deactivating regions of the default mode network, like the posterior cingulate cortex and
medial prefrontal cortex, indicating the need for focused attention and suppression of unrelated
thoughts. Subsequently, based on this comparison, the brain generates an appropriate response,
such as indicating similarity or difference between objects. Neuroimaging studies have shown
that variations in activation levels in the right posterior LOC and right supramarginal gyrus can
predict performance accuracy in mental rotation tasks, underscoring the significance of these
brain regions in facilitating successful mental rotation. Overall, mental rotation tasks activate a
network of brain regions involved in visual-spatial processing, motor simulation, and object
recognition, while individual differences in activation levels in specific regions correlate with
variations in mental rotation proficiency.
 Shepard and Metzler mental rotation task is a classic psychological experiment that was
first reported in 1971. In this task, participants are presented with two 3D abstract block figures
and have to judge whether the figures are the same or different, despite being rotated at different
angles. They found that the time participants took to make this judgment increased
monotonically with the angular disparity between the two figures. This suggested that
participants were mentally rotating the objects to make the comparison. This task has become a
central paradigm for studying mental rotation and the cognitive processes involved. It is widely
used in research on spatial abilities and mental imagery. The task is assumed to involve a series
of sequential cognitive processing stages, including perceptual encoding, identification of the
stimulus, mental rotation, judgment of parity, and response execution. However, the
interpretation of mental rotation as a single, holistic process has been challenged, with some
evidence suggesting a more piecemeal, non-holistic process of rotating object parts or
components.
Yuille and Steiger (1982) in their paper challenges the prevailing "holistic" view of
mental rotation, which suggests that objects are rotated as complete, integrated representations.
The experiments in the paper used a modified version of the classic Shepard and Metzler mental
rotation task to investigate whether mental rotation involves a more piecemeal, "non-holistic"
process. The results provided "suggestive evidence" that mental rotation may not be a single,
holistic process, but rather involves the sequential rotation of different parts or components of the
object. This suggests the brain does not necessarily rotate the entire object representation as a
single unit, but may break it down and rotate the parts in a more piecemeal fashion. The findings
imply that mental rotation is a more complex cognitive process than previously thought,
involving the coordination of multiple sub-processes rather than a single, unified operation.
The experiment by UKEssays (2018) investigated the relationship between the angle of
rotation and reaction time. Participants were asked to mentally rotate images to determine if they
were mirrored or rotated. The results showed that reaction time increased as the angle of rotation
increased, but then decreased at larger angles. This supports the hypothesis that reaction time
increases as the angle of rotation changes. The study by Lamb and Robertson (1990) examined
the effect of visual angle on global and local reaction times. The results showed that there is a
transition from a global to a local advantage in reaction time as visual angle increases. This
suggests that higher level processes, such as attention, play a role in determining the relative
speed of processing of local and global-level information.
Hypothesis
The larger the angle of rotation between two shapes, the more reaction time.
Method
Sample
Total number of subjects that participated in the study were 16 between the ages of 20- 27
yrs. old. All are students of CCS university, Meerut.
Test and tools
A computerized Metal rotation task design in Psychopy V.2023 was used. The experiment
was done on Lenovo laptop with 15 inches screen.
Design and procedure
The aim to study the effect of angle of rotation on reaction time in Mental Rotation task.
Mental rotation task in Psychopy software was self-administered on 16 subjects. The study was
carried out in quiet environment, initially the participants were shown 2D images of Letter ‘F’.
The task begins with clear instructions provided to participants, explaining the task and its
requirements. Participants are informed that they need to respond as accurately and quickly as
possible during the task. Participants need to look at the alphabets F presented at the screen and
recognize whether the stimulus pair are same or different after rotating the images. The stimuli
include various orientations, including the original upright position and rotated versions in
increments (e.g., 0°, 45°, 90°, 135°, etc.). Including both normal and mirror-image versions of
the stimuli. The stimuli are presented one pair at a time, with one stimulus in the left and the
other in right. Participants are asked to indicate whether the left stimulus matches the right one or
is a mirror image, by pressing corresponding keys (M for same images and N key for different
images).
The task consists of one example in the beginning and total of 32 experimental trials.
When subject is ready to start the example is shown initially to familiarize participants with the
task and response requirements. After that the actual task begins automatically. When participant
complete the experiment then analyses of the collected data is done, response time for correct
answers is calculated for each of the 8 angles. Initially the number of participants were 16 but 3
samples were removed as their data were very high. The data of all the participants were
statistically analyzed using SPSS software to calculate ANOVA.
Results
The aim of the study is to study the effect of angle of rotation on reaction time in mental
rotation task. The obtained results are given below. Table 1 shows the mean, standard deviation
and standard error of reaction time for different angles of rotation. Figure 1 shows the mean
differences of reaction time.
Table 1

Shows the Mean, Standard deviation and Standard error of reaction time for different angles of
rotation

Angle Mean SD SE
0 1.421 .3376 .090
45 2.247 1.310 .350
90 1.930 .810 .217
135 2.469 .989 .264
180 2.806 1.444 .386
225 2.1303 .8270 .221
270 2.122 .8893 .238
315 1.921 1.110 .297

Mean reaction time for angles 0 (M=1.421, SD=.090), 90 (M=1.931, SD=.217) and 315
(M=1.922, SD=.297) is less than angles 135 (M=2.469, SD=.264) and 180 (M=2,806, SD=.386).
Table 2

Shows the sum of squares, mean squares, df, F-ratio, and significance level of scores of
participants.
Source Type III Sum df Mean F Sig.
of Squares Square
Intercept 761.683 1 761.683 54.198 .000
Error 168.643 12 14.054

For df=13, F=171.068 (p=0.000) is significant at p<0.01. The null hypothesis is rejected
and the alternate hypothesis “The larger the angle of rotation between two shapes, the more
reaction time.” is accepted. There are 99 out of 100 chances that if the study is repeated in future,
similar results will be obtained. The difference is real and not due to chance factor.

Figure 1
Means of reaction time for different angles

2.5
Mean reaction time

1.5

0.5

0
1 2 3 4 5 6 7 8
Angle

Liner trend for F= 171.068 is significant at p<0.01. This can be seen from the graph that
reaction time increases till angle 180° and at this angle, the participant took the most time to react
(M = 2.8061, SD = 1.44411). After an angle of 180°, the reaction time decreases at an angle of
225° (M = 2.1303, SD = .82709). A slight decrease can be seen in reaction time when the angle is
270° (M = 2.1222, SD = .88938). The lesser reaction time can be seen at an angle of 315° (M =
1.9218, SD = 1.11095).
Discussion

The aim is to study the effect of angle of rotation on reaction time in Mental Rotation
task. The study was done on post- graduation students between the ages of 20-27 years old. A
computerized Metal rotation task design in Psychopy V.2023 was used to administer the task.
Our hypothesis was “The larger the angle of rotation between two shapes, the more reaction
time”, this hypothesis was formed based on previous research studies in the field. Seminal work
from Georgopoulos and Massey (1987) revealed a linear increase in reaction time (RT) as a
function of increasing instruction angle, for angles of 5, 10, 15, 35, 70, 105 and 140°. Similar to
this study Neeley and Heath (2010) studied visuomotor mental rotation (VMR) task, participants
executed center-out reaching movements to locations deviating from a visual cue by
predetermined angles. The results revealed a linear increase in response time as a function of
instruction angle for angles of 0, 5, 10, 15, 35, 70, 105 and 140°.
The study was carried out in quiet environment, initially the participants were shown 2D
images of Letter ‘F’. The task begins with clear instructions provided to participants, explaining
the task and its requirements. Participants are informed that they need to respond as accurately
and quickly as possible during the task. Participants need to look at the alphabets F presented at
the screen and recognize whether the stimulus pair are same or different after rotating the
images. Participants are asked to indicate whether the left stimulus matches the right one or is a
mirror image, by pressing corresponding keys (M for same images and N key for different
images).
Initially the number of participants were 16 but 3 samples were removed as their data
were very high. The data of all the participants were statistically analyzed using SPSS software
to calculate measures ANOVA The results of this study provide strong support for this
hypothesis, as the p-value was found to be significant at the p<0.01 level i.e. our hypothesis “The
larger the angle of rotation between two shapes, the more reaction time.” is accepted.
The implications of this study are significant, as they highlight the importance of
considering the angle of rotation when designing tasks that require spatial processing and
rotation. This information can be used to optimize task design and improve performance in
various domains, such as computer graphics, engineering, and architecture.
In conclusion, the results of this study provide strong evidence for the relationship
between angle of rotation and reaction time. The findings support the hypothesis that the larger
the angle of rotation, the longer the reaction time. This study contributes to our understanding of
the cognitive processes involved in spatial processing and rotation, and has implications for task
design and performance in various domains.
Reference
Georgopoulos, A. P., & Massey, J. T. (1987). Cognitive spatial-motor processes. 1. The making
of movements at various angles from a stimulus direction. Experimental Brain Research,
65(2), 361-370.
Lamb, M.R., Robertson, L.C. The effect of visual angle on global and local reaction times
depends on the set of visual angles presented. Perception & Psychophysics 47, 489–496
(1990). https://doi.org/10.3758/BF03208182
Neely, K. Heath, M. (2010). Visuomotor mental rotation: Reaction time is determined by the
complexity of sensorimotor transformations supporting the response. Journal of Vision,
10(7):1072, 1072a, http://www.journalofvision.org/content/10/7/1072,
doi:10.1167/10.7.1072.
Shepard, R. N., & Metzler, J. (1971). Mental rotation of three-dimensional objects. Science,
171(3972), 701-703.
Yuille, J. C., & Steiger, J. H. (1982). Nonholistic processing in mental rotation: Some suggestive
evidence. Perception & Psychophysics, 31(3), 201-209.
UKEssays. (November 2018). Angle Of Rotation Changes Psychology Essay. Retrieved from
https://www.ukessays.com/essays/psychology/angle-of-rotation-changes-psychology-
essay.php?vref=1
Appendix
S.No 0 45 90 135 180 225 270 315
1. 1.946975 3.966309 2.323326 2.413177 3.458186 2.566575 3.452407 3.672013
2. 1.390744 3.871887 1.816785 2.169514 2.847588 2.374284 1.778723 1.623918
3. 1.767507 1.162647 1.568087 2.615888 2.559921 1.972178 2.551795 1.689259
4. 1.606556 3.060225 2.699146 2.678437 2.132573 2.312632 3.587989 1.566851
5. 1.372197 1.954837 2.839324 3.016468 2.828721 1.810578 1.892476 1.351649
6. 1.776574 1.557726 2.16753 2.84463 6.094642 2.207666 2.536606 5.021504
7. 1.186288 1.537452 2.143717 4.229634 1.773659 1.820559 1.956611 1.402894
8. 1.0718 1.516117 1.76592 1.871271 2.362778 2.87381 1.457153 1.80542
9. 1.319335 1.984833 2.36936 4.179754 5.673077 4.369983 3.398271 2.187473
10. 0.984623 1.063227 1.295983 1.3638 2.99601 1.877685 1.944934 1.192007
11. 1.337741 5.358712 0.813477 1.183536 1.337275 0.919132 1.264502 1.402404
12. 1.345656 1.795436 3.514991 2.87369 1.821436 1.990818 1.966507 1.937143
13. 0.882724 0.990385 0.981459 2.293494 2.060216 1.572912 1.318563 0.927376
14. 1.911622 1.640558 0.733463 0.836748 1.338765 1.155205 0.604695 1.12523