Natural variation in female reproductive hormones does not affect contrast sensitivity.

Abigail L M Webb,Rick O'Gorman,Paul B Hibbard

doi:10.1098/rsos.171566

Abstract

Evidence suggests that females experience adaptive shifts in facial preferences across the menstrual cycle. However, recent discussions and meta-analyses suggest that these findings are equivocal. A previously unexplored question is the extent to which shifts in female preferences are modulated by hormone-dependent changes occurring in low-level vision, such as visual sensitivity. This mechanistic approach has been a novel method for investigating the extent to which complex perceptual phenomena are driven by low-level versus higher-level perceptual processes. We investigated whether the contrast sensitivity function—an early dimension of vision—is also influenced by variation in female reproductive hormones. Visual contrast thresholds were measured for 1, 4 and 16 cycles/degree gratings during the ovulatory, luteal and menstrual phases of the menstrual cycle in naturally cycling women, and women using oral contraceptives. Male participants were tested at similar time intervals. Results showed that visual contrast sensitivity does not differ according to sex, or use of oral contraception, nor does it vary relative to hormonal shifts across the menstrual cycle. These findings suggest that shifts in female preferences are not driven by changes in visual sensitivity, and are therefore likely attributable to changes in higher-level perception or cognition.

Highlights

The cycle shift hypothesis [1] suggests that certain aspects of females’ sexual preferences, including judgements of facial attractiveness, are not fixed, but vary with fluctuations in oestrogen that occur across the menstrual cycle
Findings showed that visual contrast thresholds varied with spatial frequency (F2,92 = 58.28, p < 0.001, ηp2 = 0.55), where visual thresholds were lower for low-frequency gratings
This indicates that the mechanisms of control may be operating in areas involved in cognitive appraisal and decision-making. This has been an understudied topic within discussions from both the psychophysical and evolutionary psychology literatures. These results suggest that mechanisms underlying cycle shifts in female facial preferences do not operate in low-level vision, rather, that they are likely to occur as a result of shifts that occur in higher-level visual perception

Summary

Introduction

The cycle shift hypothesis [1] suggests that certain aspects of females’ sexual preferences, including judgements of facial attractiveness, are not fixed, but vary with fluctuations in oestrogen that occur across the menstrual cycle. Oestrogen and conception probability climb from day 8 of the cycle towards peak fertility on day 14, declining markedly afterward [2,3]. This fertile period is associated with a shift of females’ preferences towards. Women display greater interest in symmetrical male faces— a physical feature that is thought to be a cue to developmental health [4]— when rating these faces for their attractiveness as short-term sexual partners [5]. Fertile women’s preferences extend to physical cues that signify immunocompetence [6,7], including preferences for faces of males with higher levels of testosterone [8], darker facial skin tone [9] and synthetically exaggerated facial masculinity [10]

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