Abbreviated form of the 7-position scale for PDD test data analysis. The major difference is that the range of values for each comparison is from -1 to +1, rather than the range of -3 to +3 in the 7-position scoring system. This process is based on the simple and robust principle that physiological reactions of greater magnitude are caused by stimuli that are more salient to the examinee due to emotional, cognitive, or behaviorally conditioned factors. See: Capps and Ansley (1992); Harwell (2000); Krapohl (1998); Van Herk (1990).