Eye-movements during number comparison: Associations to sex and sex hormones

Abstract

Multi-digit numbers are of a hierarchical nature with whole number magnitudes depending on digit magnitudes. Processing of multi-digit numbers can occur in a holistic or decomposed fashion. The unit-decade compatibility effect during number comparison is often used as a measure of decomposed processing. It refers to the fact that performance is reduced when the larger number contains the smaller unit digit (e.g. 73 vs. 26). It has been demonstrated that women show a larger compatibility effect than men, which is in accordance with their general tendency towards focusing on stimulus details during processing of visual hierarchical stimuli (local processing style). Such a local processing style has been related to higher progesterone and lower testosterone levels. One method to study individual processing styles is eye-tracking. The aim of the present study was to examine whether sex and sex hormones (estradiol, progesterone, testosterone) relate to eye movement behavior in the number comparison task. Unlike previous studies we found no evidence for sex differences in the behavioral compatibility effect. Nevertheless, women look more often and longer at individual digits and show a stronger compatibility effect in fixation durations compared to men, while men show more saccades between numbers than women. Estradiol and progesterone were related to fewer fixations and shorter fixation durations and more saccades between numbers in men, but not in women. Furthermore, the compatibility effect in the number of fixations and fixation durations was negatively related to testosterone in women. In summary, this is the first study to demonstrate sex differences and sex hormone influences on eye gaze behavior during number comparison.

Sex differences in patients with Tourette syndrome

“…This study also found that male participants ≤12 years had greater compulsions than females, but a rise in compulsions was observed in females with aging 6 . Moreover, compulsions were more strongly correlated with ADHD symptoms in males than in females in young patients with TS in another study 22 . This observation fits into the picture of more common complex motor tics in young males with TS.…”

“…Recent studies in healthy individuals have shown sex-related differences in eye movements, including shorter ocular fixation in males than females. 25,26 Ocular fixation duration has shown an inverse correlation with testosterone levels, particularly in women. 26 Whether sex-hormones levels can influence ocular fixation and/or increase the probability of ocular deviation is a hypothesis worth testing.…”

“…25,26 Ocular fixation duration has shown an inverse correlation with testosterone levels, particularly in women. 26 Whether sex-hormones levels can influence ocular fixation and/or increase the probability of ocular deviation is a hypothesis worth testing. Although disturbance in dopaminergic transmission is a major biochemical abnormality in patients with TS, disturbance of cortico-striato-pallido-thalamic-cortical networks and the relatively unique role of the insula are considered central in the pathophysiology of TS.…”

Gender Differences and Optimizing Women’s Experiences: An Exploratory Study of Visual Behavior While Viewing Urban Park Landscapes in Tokyo, Japan

“…This noted difference in eye-movement patterns is relatively new to the field of landscape perception but fits with explanations for similar differences in other fields. Schulte, Hawelka, and Pletzer (2020) [48] were the first to discover the effects of sex hormones on visual behavior in number-comparison eye-tracking experiments. They found that estradiol and progesterone were associated with more saccades and shorter fixations in men but not in women.…”

Eye-Movements During Navigation in a Virtual Environment: Sex Differences and Relationship to Sex Hormones

“…Only few studies have focused on this question so far, yielding nonsignificant associations (Harris et al, 2019). However, previous studies in related tasks suggest that eye-movements, which have a more direct link to attentional processes (e.g., Shepherd et al, 1986;Theeuwes et al, 2009;Orquin and Loose, 2013) may be more susceptible to hormonal influences than purely behavioral measures like reaction time (Schulte et al, 2020). Accordingly, we explore, whether the sex hormones estradiol, progesterone and testosterone, mediate or moderate the sex differences in performance, fixation duration and gaze distance.…”