Poster #30 - Lateralized Spatial Processing During Visual Search in Toddlers and Young Children

• In Event: 3-206 - Poster Session 13
  In Poster Session: PS 13 Section - Cognitive Processes

Integrative Statement

When encoding their environment, infants and Westernized children and adults preferentially process information (especially numerical information) from left-to-right. Adults and children in cultures whose language is scripted from right-to-left do not exhibit this spatial bias. Here, we examine the age at which left-to-right spatial associations found in infancy shift to culture-specific spatial biases, for both numerical and non-numerical information. This experiment tests the theory that toddlers are temporarily spatially ‘agnostic’, exhibiting no directional bias while absorbing the spatial norms of their culture.

There are few studies which capture this transitional period for spatial cognition. To address this issue, and test the above theory, 149 children were tested within an eye-tracking paradigm which required only passive viewing of a short video (N = 48 1 y.o.s, 38 2s, 33 3s, 11 4s, 19 5s.). This video presented a spatial transposition task, adapted from the non-human animal literature. During the first three trials, one object was hidden in a consistent location within a vertical array comprising five locations (the second location from the bottom for half the sample, top for the other half). On the fourth trial (vertical test trial), a delay was introduced in which a narrator asked where the object was hidden, before the object was revealed. On the final trial (horizontal test trial), the array was covered with an occluder, surreptitiously rotated 90o, and uncovered. The narrator prompted the child to visually search by asking them where the object was during a 5-second delay. The object was then revealed. Participants were assigned to either the Numbered condition (in which the narrator labeled each of the locations with 1, 2, 3, 4, or 5 during vertical training) or Unnumbered condition (the locations were labeled as Dax, Zif, Blick, Mot, or Wug).

To quantify horizontal visual search strategies, a repeated-measures ANOVA was conducted with number of fixations to each screen side post-transposition (left, right) as a within-subjects factor, and age and condition as between-subjects factors. There was no main effect, or interactions with, numerical / non-numerical condition. There was an overall effect of side of screen (8.7 fixations left, vs. 5.4 right, p < .001). Screen side interacted significantly with age (p=.002). 2-year-old children did not search the left side more frequently than the right (6.0 fixations L vs. 7.2 fixations right), but all other age groups did (ps = .05, .51, .02, .03, .001, respectively, all comparisons Bonferroni-corrected). To test whether this horizontal bias pattern was due to differing levels of learning during training, a univariate ANOVA over fixations to the correct location - incorrect location during the final vertical training trial was run. Vertical learning did not significantly vary with age or condition; all age groups appeared to have learned the vertical location, but 2-year-olds do not use this information to make an asymmetrical mapping.

These data support the presence of a dip in left-to-right processing at the age of 2 years, as children recede from infantile spatial biases and progress to exhibiting culture-specific spatial biases in early childhood.

Authors

• Eloise West, Barnard College
  Presenting Author

• Koleen McCrink, Barnard College
  Non-Presenting Author