Cognition Laboratory Experiments
John H. Krantz, Hanover College, email@example.com
Instructions for the
|Stimulus Type||The rotation stimulus: Random 2D figure, Letter, String, Original 2D1 and Original 3D1.|
|Number of Rotation Angles||Number of levels of rotation variable (includes 0 and 180 deg).|
|Should the left stimulus be allowed to rotate or be fixed||If the left hand stimulus is allowed to rotate, then it can assume any angle and be either the original image or the mirror image. If the left hand stimulus is fixed, it is not rotated nor will it be a mirror but always the normal image.|
|Stimulus Size||If Random 2D figure, how big is the stimulus|
|Stimulus Contrast||The brightness difference between the background and the foreground. The foreground is always darker. It is a percentage of the maximal change possible on the display.|
|Letter Stimulus to Display||If a letter figure, what letter to display|
|String Stimulus||If a string stimulus, what string to display|
|Trials per level||The number of presentations of each rotation angle|
|Font Size||If using a letter stimulus (from 12 to 64 point)|
|Distance from Fixation||How far from the fixation stimulus is the center of the stimulus (in proportion of distance from center to edge)|
|Delay before stimulus||How long between your response and the next trial|
|Stimulus on till response||Is the stimulus on until you respond or only one for a given period of time.|
|Duration of Stimulus||If stimulus is only on for a give period of time, how long is that interval.|
After you have finished making your settings, press the Done button at the bottom of the screen. The Mental Rotation experiment screen will then be presented.
Press the space bar to begin the experiment. A fixation mark will appear for the indicated time. The stimulus will be presented after the delay time. As so as the stimuli are on, you may respond. There are several ways to respond:
It is good to have your figures ready over the buttons when the stimuli are presented. After you have responded, the next trial will begin.
At the end of the experiment, your results will be presented. The results will be the reaction time and accuracy for each angle. The same image data and mirror image data will be presented separately. In accuracy, a 1.0 is a perfect performance. You can also get your trial by trial results. Closing your results window(s) will take you back to the setup window so you can run another experiment.
Cooper, L. A. (1975). Mental rotation of random two-dimensional shapes. Cognitive Psychology, 7, 20-43.
Metzler, J. & Shepherd, 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. Potomac, MD. Lawrence Earlbaum Associates.
1 The two dimensional shape referred to as Original 2D is take from form H by Cooper (1975) also used elsewhere. The orginal 3D shap is taken from Metzler & Shepherd (1974).