What infants know and what they do: perceiving possibilities for walking through openings

Abstract

What infants decide to do does not necessarily reflect the extent of what they know. In the current study, 17-month-olds were encouraged to walk through openings of varying width under risk of entrapment. Infants erred by squeezing into openings that were too small and became stuck, suggesting that they did not accurately perceive whether they could fit. However, a second penalty condition revealed accurate action selection when errors resulted in falling, indicating that infants are indeed perceptually sensitive to fitting through openings. Furthermore, independent measures of perception were equivalent between the two penalty conditions, suggesting that differences in action selection resulted from different penalties, not lack of perceptual sensitivity.

Figure 1

Adjustable opening apparatus in (A) entrapment and (B) falling conditions. In entrapment, infants walked through bounded openings (C). In falling, infants walked along a ledge between the moving wall and a precipice (D).

Figure 2

Example of success rate data at each aperture width for one infant. Dashed lines mark the 67% success threshold. The bottom x-axis shows relative risk in centimeters: opening size normalized to the success threshold.

Figure 3

Infants’ success thresholds in the entrapment and falling conditions. Each circle shows data for one infant. Horizontal bars indicate means.

Figure 4

Infants’ rates of (A) attempts, (B) prospective turning, and (C) approaching in entrapment (filled circles) and falling (open squares) conditions. Vertical dashed line in (A) represents each infant’s success threshold. Negative numbers on the x-axis denote impossible openings; positive numbers indicate possible openings.