Mental Rotation

(Editor:   James Collins)

Introduction

An aspect of cognitive performance that yields strong between-person differences is the ability to manipulate spatial information. One of the most popular tasks used in measuring individual differences in spatial ability is a mental rotation task introduced by Shepard and Metzler (1971). The time that one needs to rotate an object mentally correlates with the time that one would need to rotate it physically.

Studies of mental rotation have revealed that people take longer to make judgments of rotation as the angular disparity between the two figures increased. Just as it takes more time to physically rotate an object over a greater distance, greater mental rotations of imagined objects also require more time and presumably more effort. This time difference disappears when participants receive advance information about the relative positions of the objects. The internal, mental images appear to represent the corresponding physical objects.

Design

This experiment presents 16 different pairs of three dimensional objects. Users judge whether the objects are the same or different. Responses are timed. Judging whether stimuli are the same or different is made difficult by the fact that the paired objects are not in the same orientation. The left object is always in an upright position but the paired object on the right is rotated in 45 degree steps from 45 degrees to 315 degrees. On each trial, a different one of the 16 possible object pairs appears in random order. Eight are identical object pairs and eight are mirror image pairs. Independent variables include whether the stimuli match and the degree of rotation of the stimulus compared to the standard. Additional variables of interest include gender and age of the participants. Male participants typically are faster than female participants in performing mental rotation, and young adults are faster than children and elderly adults (Burnett, 1986).

Data Analyses


There are two within-subject variables to be investigated. One is rotation angle and the other is pair type (e.g., match or mismatch). A graph like the one below provides a convenient display of the effects of these variables, which can be analyzed for significance using a 2 X 7 repeated measures analysis of variance.

Sample graph image from the Mental Rotation study
Figure 1

Applications and Extensions

Recent research in this area has sought to discover ways to train mental rotation and similar spatial abilities, erasing gender differences (Lizarraga & Ganuza, 2003). Functional MRI images of brains engaged in mental rotation tasks have also been obtained (Cohen et.al., 1996; Richter, Ugurbil, Georgopoulous, & Kim, 1997).

Data Format & Download



Sample data image from the Mental Rotation study
Figure 2

Data are compiled in the excel spreadsheet or in a comma delimited file with the following labels:

USERID - is the value assigned to the individual participant.
CLASSID - is the value affiliated with the registered course.
GENDER, AGE, DATE - are self explanatory columns.
ANG0TIME-ANG315TIME - Data in these columns reflect the average response times for three trials for each of the angles. For example, there are 3 trials for the 0 degree angle and the data in this column reflect the average response time for these trials. All of the trials present an upright figure and rotated figure that are actually the same figure.
DANG0TIME-DANG315TIME - Data in these columns reflect the average response times for three trials for each of the angles. For example, there are 3 trials for the 0 degree angle and the data in this column reflect the average response time for these trials. All of the trials present an upright figure and a rotated figure that are mirror images of each other, hence they are different figures.
ANG0COR-ANG315COR - data recorded in these columns reflect the number of correct responses for each of the angles. Scores can range from 0-3 based on 3 trials for each angle. These data reflect responses for the rotations that are the same.
DANG0COR-DANG315COR - data recorded in these columns reflect the number of correct responses for each of the angles. Scores can range from 0-3 based on 3 trials for each angle. These responses reflect responses for the rotations that are different.

References 

Burnett, S. A. (1986). Sex-related differences in spatial ability: Are they trivial? 
	American Psychologist, 41, 1012-1014.

Cohen, M. S., Kosslyn, S. M., Breiter, H. C., DiGirolamo, G. J., Thompson, 
	W. L., Anderson, A. K., Bookheimer, S. Y., Rosen, B. R., & Belliveau, J. W. (1996). 
	Changes in cortical activity during mental rotation: A mapping study using 
	functional magnetic resonance imaging. 	Brain, 119, 89-100.

Lizarraga, M. L. & Ganuza, J. M. (2003). Improvement of mental rotation in 
	girls and boys. Sex Roles  49, 277-286.

Metzler, J. & Shepard, R. N. (1974). Transformational studies of the internal 
	representation of 	three-dimensional objects. In R L. Solso (Ed.), 
	Theories of cognitive psychology: The Loyola symposium (pp.147-202). 
	Potomac, MD: Lawrence Erlbaum.

Richter, W., Ugurbil, K., Georgopoulos, A., & Kim, S. (1997). Time-resolved fMRI of 
	mental rotation. Neuroreport, 8, 3697-3702.