Memory confusions for real and imagined completions of symmetrical visual patterns

In Experiment 1, subject ratings indicated that it was easier to imaginally complete half of a symmetrical form when the form was symmetrical about the vertical axis than when the form was rotated so that it was symmetrical about the horizontal axis. In Experiment 2, new subjects saw these same forms, some presented as wholes and some presented as halves. Compared with controls, subjects who were instructed to imagine the vertically symmetrical half forms as complete had more difficulty remembering which forms had been presented as wholes and which had been presented as halves. Imagery and control groups did not differ in ability to discriminate half from whole horizontally symmetrical forms. The results are consistent with predictions from Johnson and Raye’s (1981) reality monitoring model that discriminating memories of imagined and perceived events should be a function of the amount of cognitive operations included in the memory.