Early contributions to infants’ mental rotation abilities

Abstract

Some cognitive abilities exhibit reliable gender differences, with females outperforming males in specific aspects of verbal ability, and males showing an advantage on certain spatial tasks. Among these cognitive gender differences, differences in mental rotation are the most robust, and appear to be present even in infants. A large body of animal research suggests that gonadal hormones, particularly testosterone, during early development could contribute to this gender difference in mental rotation. Also, substantial evidence supports an influence of socialization on mental rotation performance. The present study investigated the relationship of two types of factors, early postnatal testosterone exposure and parental attitudes about gender, to mental rotation performance in 61 healthy infants (29 males, 32 females). We measured salivary testosterone at two time points: 1-2.5 months of age and 5-6 months of age. Infants' mental rotation performance and parents' attitudes about gender were assessed at 5-6 months of age. As predicted, testosterone concentrations were significantly higher in boys than girls in early infancy (d = 0.54), and boys performed significantly better than girls on mental rotation (d = 0.64). A significant positive correlation between testosterone at age 1-2.5 months and mental rotation was found only in boys (r = 0.50, p = .01). A significant negative correlation between parents' gender-stereotypical attitudes and mental rotation performance was found only in girls (r = -.57, p = .002). These findings suggest that the early postnatal testosterone surge (also known as "mini-puberty") may have organizational influences on mental rotation performance in boys, and that parents may influence their daughters' mental rotation abilities beginning very early in life.

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

“…The timing of this surge is thought to be potentially important to human cognitive development (Lyall et al, 2015) because it occurs during a period of rapid cortical development, some of which is occurring in regions of the brain that appear to be active during MR in adults (Gogos et al, 2010;Schendan & Stern, 2007;Schöning et al, 2007). Constantinescu et al (2018) replicated the sex difference in MR performance reported by Moore and Johnson (2008), and they also found a significant positive correlation between boys' early postnatal testosterone exposure and their MR performance when tested at 5 months. Thus, hormonal events during "mini-puberty" might have lasting organizational influences on boys' central nervous systems, influences that affect their MR competence later in infancy.…”

“…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.…”

“…Moore andJohnson (2008, 2011) presented the objects seen in panels a and b in alternation in a series of 6 test trials. Adapted from Constantinescu et al (2018), Fig. 2 By coincidence, a second paper on infants' MR was published alongside the Moore and Johnson (2008) report in the same issue of Psychological Science.…”

“…Another recent study examined the relation between MR performances in 5-to 6-month-olds and their levels of salivary testosterone measured several months earlier, when they were 1 to 2.5 months of age (Constantinescu et al, 2018). This period between the first and third postnatal months has been called "mini-puberty" (Lamminmäki et al, 2012) because of a surge in testosterone that is especially large in boys at this time (Corbier et al, 1992;Gendrel et al, 1980;Hammond et al, 1979).…”

“…Test stimulus objects used byChristodoulou et al (2016),Constantinescu et al (2018),Heil et al (2018),…”