Question

Identifying Research Designs

For each of the examples below, state whether the research is a between-subjects (between-groups) or within-subjects (within-groups/repeated measures) design.

1. How do people mentally represent and manipulate physical objects in their minds? Shepard and Metzler (1971) conducted one of the earliest experiments to investigate the use of spatial representations. They aimed to determine whether mental manipulations were analogous to (or paralleled) manipulations of actual physical objects. In their classic work, they asked participants to determine whether two three-dimensional block figures, presented in different orientations, were the same or different. The mental rotation experiment uses a 2 (stimuli relationship: same or different) x 8 (angular difference in orientation: 0, 45, 90, 135, 180, 225, 270, 315) design, yielding 16 conditions. The experiment begins with two practice trials in which you indicate if two three-dimensional block stimuli are the same or different. In the actual experiment, there are 48 trials, including three "same" and three "different" trials for each angular difference. The stimulus on the left is always at the same angular orientation; the angular difference between the stimulus on the left and the one on the right varies randomly across trials. The program measures two dependent variables: number correct (from 0 to 3 for each stimuli relationship/angular difference condition) and response time (measured in seconds).

Answer 1

The research is within-subjects (within-groups/repeated measures) design.

Explanation:

Within-subjects (within-groups/repeated measures) design involves multiple measurements of the same variables using only one group of subjects, where tests on each subject are repeated more than once after each different treatment. In the given experimentation, there is only one group of participants for studying the effect of 48 trials, including three "same" and three "different" trials for each angular difference on two dependent variables: number correct (from 0 to 3 for each stimuli relationship/angular difference condition) and response time (measured in seconds).