Mental Rotation in Infancy: 9-Month-Old Infants Profit from Rotational Hand Movements

• In Event: Poster Session 10
  In Poster Session: PS 10 Topic - Perceptual, Sensory, Motor

Abstract

Studies show that the opportunity to explore an object prior to seeing it in a mental rotation task enhances infants’ performance on that task (e.g. Slone, Moore, & Johnson, 2018). The current study investigated the question of which part of the manual exploration leads to this beneficial effect. Prior studies (Schwarzer, Freitag & Schum, 2013; Ruff, 1984) suggest that two candidate procedures might be rotations and haptic scans. In order to test which of these manual exploration procedures performed prior to a mental rotation task leads to enhanced spatial object processing, we constrained infants’ exploratory experiences with a Shepard-Metzler object in two Experiments by presenting it in an apparatus that allowed either only rotations (Experiment 1) or haptic scans (Experiment 2). As another potential contributing factor influencing mental rotation performance crawling experience was included in the analyses.
Twenty-four 9-month-olds (9 m, 15 f) participated in Experiment 1. Eleven of them had crawling experience for at least 4 weeks and were therefore defined as crawlers. Infants could rotate a simplified Shepard-Metzler object around 240° for three minutes. Afterwards they were tested for mental rotation by watching the original- and the mirror object consecutively rotating through the left 120° in a continuous motion. Looking-times were recorded.
The analysis is based on preference scores (in %) for the mirror object. The scale value for the cognitive scale of the Bayley III was included to control for cognitive development. A one-way ANCOVA (crawlers vs. non-crawlers) revealed a significant effect for crawling experience (F[1, 21] = 5.81, p = .025, partial η2 = .217) and no effect of cognitive development (F < 1, ns.). A post-hoc analysis indicated a significant familiarity preference in the crawling infants (t[10] = -3.02, p = .026, Cohen’s d = -.91, Bonferroni corrected), whereas non-crawling infants performed at chance level (t < 1, ns.).
To see if this effect is specific for crawling infants’ rotational hand movement experience, a second experiment was conducted, including twenty-seven 9-month-olds (14 m, 13 f; 13 crawlers, 14 non-crawlers). Infants could explore the object by executing haptic scans on the fixed object, which was presented from three perspectives for one minute each, covering the 240° that infants saw in Experiment 1. The mental rotation test in Experiment 2 equals Experiment 1.
A one-way ANCOVA (crawlers vs. non-crawlers) revealed no significant group differences (F < 1, ns.), and again, no effect of cognitive development (F[1, 24] = 1.92, p = .18). Post-Hoc tests revealed no significant preferences, neither in crawling infants (t < 1, ns.) nor in non-crawling infants (t < 1, ns.).
The results suggest, that crawling experience enables infants to use the information gathered through manual rotations of an object for mentally rotate, and recognize it from an unfamiliar perspective, while haptic scanning might not have a beneficial effect on mental rotation in infancy.

Authors

• Amanda Kelch, Justus-Liebig-University Giessen
  Presenting Author

• Gudrun Schwarzer, University of Giessen
  Non-Presenting Author

• Gloria Gehb, Justus-Liebig-Universität Gießen
  Non-Presenting Author

• Bianca Jovanovic, University of Giessen
  Non-Presenting Author