Stephanie Kubota CAS PS336 Professor Howard April 25 13 CogLab Experiment Mental Rotation PS336 Cognitive Psychology Professor Mark Howard Written by Stephanie Kubota 1 Stephanie Kubota CAS PS336 Professor Howard April 25 13 Introduction Shepard and Metzler s 1971 concept of mental rotation is one of the most well known experiments in cognitive psychology It is the pioneering experiment that used graphical images through collaborating with computer science which earned its first publication on the cover of Science journal Mental rotation is one s ability to rotate mental representations of two or three dimensional objects similar to the way we visually perceive and recognize other objects in our external environment This concept has been associated with one s rate of spatial processing and intelligence Johnson 1990 and has also been used to understand how one recognizes objects in the environment The CogLab Mental Rotation Experiment uses mental rotation to measure the time that subjects require to identify the difference in the shape and orientation between two graphical images presented The following hypothesis is presented H1 changes in the orientation of two presented identical or unidentical objects affect the amount of time one spends in deciding whether or not the objects are the same Methods and Procedure The experiment presents the subjects with several pairs of three dimensional complex shapes made of cubes as shown in the Figure 1 The two shapes presented were either identical or a mirror image of the other furthermore one of the shape is rotated clockwise 0 20 40 60 80 100 or 120 degrees relative to the orientation of the other shape The subjects were asked to determine whether the two shapes were the identical or unidentical as quickly as possible If the subject answers incorrectly the specific trial is repeated later in the experiment CogLab The subjects were given 50 sets of trials With that in mind the following variables are presented 2 Stephanie Kubota CAS PS336 Professor Howard April 25 13 Control variable the average time it takes for a subject to decide and report that the given shapes are identical at 0 of rotation Independent variable the orientation of one of the two shapes presented relative to the other degree of rotation Dependent variable the amount of time required for the subject to make the decision response time Figure 1 Examples of the set of shapes presented in the experiment Empirical Description The results of Shepard and Metzler s original experiment produce a linear function The function describes that the relationship between the response time and the degree of rotation increased in direct proportion In relation to mental rotation it is as if the subjects were rotating the mental representation of the given shapes at a steady rate the further the subject had to rotate the shapes in in their mind in order to correspondence to the presented image the longer the response time As shown in Figure 2 the mean reaction times for subjects increased from a value 3 Stephanie Kubota CAS PS336 Professor Howard April 25 13 of about 1 second at 0 of rotation to values ranging from 4 to 6 seconds at 180 of rotation Furthermore it also visible that for every 60 of rotation the reaction time increases by a second Shepard Metzler 1971 Figure 2 Shepard and Metzler s Average Data 1971 However the CogLab Mental Experiment Global Average Data shown in Figure 3 results presented an exponential function where the increase in reaction time becomes smaller when the degree of rotation becomes larger Moreover the reaction time was also shorter than 4 Stephanie Kubota CAS PS336 Professor Howard April 25 13 that of Shepard and Mezler s experiment The CogLab Experiment s reaction time was measured in milliseconds with a maximum reaction time of approximately 3 200 milliseconds while Shepard and Mezler s experiment was measured in second with a maximum reaction time of approximately 6 seconds The Global Average Data also reports that there is a longer reaction time when the subjects had to identify unidentical shapes than identical shapes additionally the increase in reaction time as the degree of rotation increases is smaller when identifying unidentical shapes than that of identical shapes However it is still evident that there is an increase in reaction time as the degree of rotation increases herein the average increase in reaction time is about 250 milliseconds for every 20 of rotation when subjects had to identify identical shapes Figure 3 Global Average Data The Group Average Data shown in Figure 4 is similar to the Global Average Data in that it also presents an increase in reaction time and degree of rotation except that there is a decrease in reaction time from 100 to 120 of rotation when subjects were asked to identify 5 Stephanie Kubota CAS PS336 Professor Howard April 25 13 identical shapes The reaction time in the Group Average Data is also relatively shorter than that of the Global Average Data the maximum reaction time of the Group Average Data is approximately 2 900 milliseconds However it is still evident that there is an increase in reaction time as the degree of rotation increases herein the average increase in reaction time is about 300 milliseconds for every 20 of rotation when subjects had to identify identical shapes On the other hand the Group Average still shows that there is a longer reaction time when the subjects had to identify unidentical shapes than identical shapes the increase in reaction time as the degree of rotation still increases is smaller when identifying unidentical shapes than that of identical shapes Figure 4 Group Average Data On the other hand the Individual Average Data does not closely resemble the Global Average as much as the Group Average Although the individual subject s report does not present a consistent pattern of reaction time depending on the degree of rotation there is still an increase in reaction time as the degree of rotation increases from 0 to 80 of rotation Moreover 6 Stephanie Kubota CAS PS336 Professor Howard April 25 13 the Personal Average does not follow the pattern that shows an increase in reaction time as the degree of rotation increases is smaller when identifying unidentical shapes than that of identical shapes On the other hand the Group Average still shows that there is a longer reaction time when the subjects had to identify unidentical shapes than identical shapes there is a decrease in