PSY 405 – Spring 2012
Deng Jichun
Introduction The purpose of this experiment was to confirm the theory that we create picturelike representation of perceived visual stimuli, and we can also mentally rotate the representation to a known “upright” position. The reaction time increases linearly according to the angle of the rotation, regardless of their complexity (Cooper, 1975). In some circumstances, we snap the perceived visual stimuli and create a picturelike image in head. The process of mentally rotating the image inevitably takes time, and the length of the reaction time indicates how much effort we put in it. That means the reaction time represents the mental effort, and vice versa. It’s reasonable that as the angle of rotation increases, the more effort will be needed which results in linear increase in reaction time. We mentally rotate the image in head as a whole just like physically rotating exist pictures, the complexity of the image won’t impact the reaction time within some certain degree. When the image is complex enough (such as 3-D images), the time we need to “snap and copy” it increases. Also during the rotation, more reaction time will be needed because the time we spend verifying the correctness of the image increases (Shepard & Metzler, 1988). In this experiment, we use 3-D images to confirm the hypothesis of Cooper’s theory that as the angle of rotation increases, the reaction time linearly increases accordingly.
Method
Participants Participants included twenty-eight undergraduate students in Cognitive Psychology Course.
Mental Rotation Task The mental rotation task consisted of at least 70 trials presented on the computer monitor (Francis, Neath, & VanHorn, 2008, pp. 105-107). On each trial, participants saw two 3-D block shapes, one to the left and one to the right. Each block shape is within a circle. The two shapes were either identical, or mirror-reversed. One shape was also
References: Francis, G., Neath, I., & VanHorn, D. (2008). CogLab 2.0 on a CD. Belmont, CA: Thomson. Cooper, L. A. (1975). Mental rotation of random two-dimensional shapes. Cognitive Psychology, 7, 20-43. Shepard, S., & Metzler, D. (1988). Mental rotation: effect of dimensionality of objects and type of task. Journal of Experimental Psychology, 14(1), 3-11.