Often it was investigated whether the type of image displayed had any effect on the results. For example, a study performed by Cooper (1975) introduced the use of complex two-dimensional objects to examine the reaction times (p. 21). They hypothesized that the more complex and unfamiliar the object, the longer it might take to be angularly rotated back to the original position (Cooper, 1975, p. 22). A second, separate study by Cooper and Shepard (1973) introduced the use of alphanumeric characters, which most participants seem to be familiar with (p. 76). Because of the relevance to everyday life, it is important to understand how the phenomenon of mental rotation works. With each of the additional studies on the topic, the procedures remained similar in presenting two separate items at different angular orientations and requesting the subjects to determine whether the second item was the same as the original, or a mirror image of it. Each of these studies discovered results that were replicable with the original experiment; the reaction times of the participants increased as the angular rotation of the object also increased, regardless of whether it was two-dimension, three-dimensional, or alphanumeric characters (Cooper, 1975; Cooper & Shepard, 1973; Shepard & Metzler, 1971). These results support the theory that mental rotation is occurring, because the further away from the axis that the object is rotated the longer it would take for a subject to mentally rotate it to the original position and then determine whether or not it is a mirror
Often it was investigated whether the type of image displayed had any effect on the results. For example, a study performed by Cooper (1975) introduced the use of complex two-dimensional objects to examine the reaction times (p. 21). They hypothesized that the more complex and unfamiliar the object, the longer it might take to be angularly rotated back to the original position (Cooper, 1975, p. 22). A second, separate study by Cooper and Shepard (1973) introduced the use of alphanumeric characters, which most participants seem to be familiar with (p. 76). Because of the relevance to everyday life, it is important to understand how the phenomenon of mental rotation works. With each of the additional studies on the topic, the procedures remained similar in presenting two separate items at different angular orientations and requesting the subjects to determine whether the second item was the same as the original, or a mirror image of it. Each of these studies discovered results that were replicable with the original experiment; the reaction times of the participants increased as the angular rotation of the object also increased, regardless of whether it was two-dimension, three-dimensional, or alphanumeric characters (Cooper, 1975; Cooper & Shepard, 1973; Shepard & Metzler, 1971). These results support the theory that mental rotation is occurring, because the further away from the axis that the object is rotated the longer it would take for a subject to mentally rotate it to the original position and then determine whether or not it is a mirror