Comparisons of the mean proportions of crawling, upright, and walking bouts that co-occurred with (A) overall gesture input, (B) movement gestures that beckoned infants, and (C) show gestures that individuated objects in space. Solid lines are data for crawling bouts; dotted lines for upright bouts; and dashed lines for walking bouts. Error bars show standard errors. Asterisks denote statistical significance in pairwise comparisons between bout types: *p < .05, **p < .01, ***p < .001