Sex-based differences in answering strategy and the influence of cross-sex hormones

We investigated whether sex differences in answering strategy occur in normal controls (C). Furthermore, it was tested whether these sex differences were subject to change over time, and whether they were associated with hormonal treatment at time points 2 and 3 in patients with Gender Identity Disorder (GID). Two subtests measuring arithmetic ability were used: arithmetic aptitude (AA) and arithmetic operations (AO). Both the controls (n = 29) and GID patients (n = 33) were tested at baseline (T1), three months (T2) and 12 months (T3) after the start of hormonal treatment in the GID group. A repeated measures analysis of variance showed no differences between C males and females, for T1 and T2. At T3, C males guessed more than C females. At baseline, GID males and C males left an equal number of items unanswered. However, when being retested, C males left fewer items unanswered than GID males. No difference was found between C females and GID females at any time point. Our results suggest that healthy adult males become more confident when they are retested, and seem to adjust their answering strategy accordingly. Moreover, hormonal treatment of healthy adult GID patients born male is associated with a lack of adjustment in answering strategy.