Infants' looking times in a 2‐D mental rotation task

Abstract

In adults, substantial and consistent sex differences during mental rotation favouring men are obtained as long as certain methodological boundary conditions are met. In recent years, a number of studies using different stimuli and experimental approaches investigated sex differences in mental rotation in infants with inconclusive results. The goal of the present study was to examine on the basis of a sufficient statistical power (a) whether infants aged 6 month are able to use mental rotation in a preferential looking task after familiarization with simple 2‐D stimuli; (b) whether there were sex differences present, and (c) whether the results depend on inducing an expectation about the orientation of the upcoming stimulus. Our data suggest that the familiarization paradigm is well suited to reveal sex differences in mental rotation favouring boys only when it induces an expectation about the orientation of the upcoming stimulus. If no such expectation is induced, neither boys nor girls reveal evidence for mental rotation. More studies are needed to evaluate sex differences in infancy and, more importantly, whether infant's sex differences are restricted to experimental paradigms that induce the extrapolation of an induced rotary movement. Highlights We investigated the reliability of recent findings suggesting that male but not female infants show evidence for mental rotation although no expectation about the orientation of the upcoming stimulus was possible. By measuring the novelty preference in looking times, we found no evidence for mental rotation and no evidence for a sex difference as long as no expectation about stimulus orientation was possible. Since the sex effect was only present when an expectation of stimulus orientation was induced, the ability of rotary extrapolation might be the reason for sex effects sometimes present in infant research on mental rotation.

Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants

“…Although our overall results promote the general assumption of sexually dimorphic hands and digits as well as different hand and digit measures, our study deals with several limitations that may be important in the context of sexually dimorphic anthropometric measurements in very young cohorts. As the initial study and the subsequent study design did not primarily investigate sex differences in hand and digit measures but mental rotation 43 , the decision to examine a cohort of 6-month-olds was based on other theoretical considerations and hypotheses that did not focus on digit ratios as markers for prenatal androgen exposure. Furthermore, we acknowledge that while the results of the present sample regarding digit measures are based on a large sample of 763 infants, we could only measure hand width and length from 180 infants.…”

“…Families with 6-month-old infants came to the Department of Experimental Psychology at Heinrich-Heine-University Düsseldorf in order to take part in a mental rotation experiment [see 43 ]. Informed consent was obtained from all parents and/or legal guardians of participating infants.…”

Spatial thinking in infancy: Origins and development of mental rotation between 3 and 10 months of age

“…Early work on rotating objects did not reveal sex differences (Hespos & Rochat, 1997;Mash et al, 2007;Rochat & Hespos, 1996), but both of the first studies of MR that required infants to recognize a rotated object and discriminate it from its mirror image reported a sex difference favoring males (Moore & Johnson, 2008;Quinn & Liben, 2008). Since then, three additional studies in our labs (Constantinescu et al, 2018;Moore & Johnson, 2011; and three additional studies in three other labs (Kaaz & Heil, 2019;Lauer et al, 2015;Quinn & Liben, 2014) have reported a male advantage in MR in infants 10 months of age or younger. In contrast to these eight studies, two studies in our labs (Christodoulou et al, 2016;Slone et al, 2018) and six studies in three other labs (Erdmann et al, 2018;Gerhard & Schwarzer, 2018;Schwarzer et al, 2013, b) have reported no sex differences in infants from this age range.…”

The association between 2D:4D digit ratio and sex-typed play in children with and without siblings

“…As part of a larger study, German-speaking families with newborn children were recruited between 2013 and 2018 when infants were 6 months of age. Families were invited to the Institute of Experimental Psychology at Heinrich Heine University Düsseldorf, Germany, in order to take part in a mental rotation experiment (a subsample was published elsewhere, see 46 ). In a follow-up 3.5 years later, parents were asked to rate their child’s sex-typed behavior with the PSAI using an online questionnaire, whether children have siblings and whether and for how long they attended pre-school.…”