Figure 3.

Perceptual judgments, exploratory, and affective behaviors. A: Proportion of trials in which infants attempted to crawl or walk down slopes. B: Number of discrete shifts in position on the starting platform prior to descent. C: Latency to begin descent. D: Proportion of trials in which infants touched the sloping section of the walkway with either hands or feet. E: Proportion of trials in which infants emitted positive/neutral vocalizations. F: Proportion of trials in which infants emitted negative vocalizations. The x-axis is labeled with the five slope increments in order of increasing risk: 4° (absolute degree of slope), −10° (10° shallower than infants’ borderline slopes), borderline slope, +10° (10° steeper than infants’ borderline slopes), and 50° (absolute degree of slope). Shading represents the difference between encourage and discourage conditions at each risk increment for crawlers and walkers. The error bars represent standard errors.