The authors found that as the

angular difference between the two configurations increased, so did participant response time. From the perspective that mental images are encoded as analogue representations (Kosslyn, 1994), Selleck CAL-101 the explanation was that it took longer for a participant to mentally rotate a shape into alignment with its comparison shape when the angle between the two was greater. Mental rotation tasks like the one used by Shepard and Metzler (1971) have commonly revealed sex differences, with males generally performing more accurately and rapidly (for reviews, see Linn & Petersen, 1985; Voyer, Voyer, & Bryden, 1995). Differences have been reported on two-dimensional rotations in preschoolers as young as 4.5 years old (Levine, Huttenlocher, Taylor, & Langrock, 1999). More recently, studies of infant spatial cognition abilities have revealed possible analogues with child and adult mental rotation performance, with differences between females and males observed between 3 and 5 months of age (Moore & Johnson, 2008, 2011; Quinn & Liben, 2008). In Quinn and Liben (2008), stimuli consisted of eight different versions of the number 1 (or its mirror image), depicted in 45° rotations from 0 to 360° (Figure 1). Infants were shown a randomly selected set of seven of the eight rotations of the number 1 (or its mirror image)

during familiarization (two identical copies per trial) and then preference tested with the remaining rotation paired with its mirror image (Figure 2). If infants perceived the novel rotation as familiar and the mirror

image as novel, then the mirror image should Ixazomib price be preferred. The key findings Crizotinib were that male infants were more likely than female infants to display a preference for the mirror image. Similarly, Moore and Johnson (2008) reported that 5-month-old males who were habituated to an object that underwent a 240° rotation were more likely than females to look longer at a mirror image of the object that was rotated through the previously unseen 120° than to the familiar object rotating through that same 120° (see also Moore & Johnson, 2011, for further evidence in 3-month-olds). Although it is clearly important to determine whether a sex difference in mental rotation is present early in development and several studies have now reported early differences, there remain questions about what might underlie the findings. Moreover, if additional findings continue to support the inference that there is a sex difference in mental rotation, it would be important to chart its developmental persistence. Experiment 1 therefore addressed the mechanism underlying the sex difference in mental rotation. Given that the data of Experiment 1 gave additional credence to the original interpretation that the sex difference observed by Quinn and Liben (2008) appears to be a gender difference in mental rotation, we conducted Experiment 2 to test whether that difference would obtain at older ages.