Psychological scaling of justice in criminal cases:
A comparison between laypersons' judgments and actual court decisions

Masashi Ida, Yuka Yatabe

Department of Psychology
Tokiwa University, Mito, Ibaraki pref., JAPAN

Presented at the XXV International Congress of Applied Psychology,
7-12 July 2002, Singapore


Court decisions in criminal cases are sometimes different from what a layperson thinks is appropriate as punishment for the offenders. In this study, university students were asked to judge what they thought were appropriate sentences for the accused in 20 real criminal cases. There is a linear function between the students' subjective judgments and actual sentences handed down by the courts. The students' judgments were more severe than those of the courts by an average of 3.6 to 5.4 years. Difference and ratio scales were obtained for laypersons' assessment of the crimes and their punishments. There is the same relation between the two scales as in other psychophysical measurements. This leads to the possibility of measuring people's subjective values in justice. Similarities were calculated from subjective judgments for summaries of 20 real criminal cases and analyzed using method of multidimensional scaling (MDS). Spatial (two-dimensional) representation of crimes is formed. It shows that a layperson perceives a crime from its degree of "intent" and "viciousness."