Since the data did not meet normality criteria, nonparametric tests
were used. Separate Mann–Whitney tests were carried out on each of
the dependent variables, i.e., mean perceived intensity of SPSs, surface
percentages, variety of SPSs, and confidence ratings with HBscore as a
categorical variable (good vs. poor heartbeat perceivers). These variables
were considered for analyses because of their good internal
consistency.1 The analyses were carried out with the Statistica (v.8)
software. The use of HBscore as a categorical variable did not allow
any result to reach significance. The data are summarized in Table 1.