Anticipating an Effect from Predictive Visual Sequences: Development of Infants' Causal Inference from 9 to 18 Months

There has been little research on infants’ development of causal inference in the second year after birth. We report an experiment in which 9to 18-month-old infants viewed visual sequences consisting of three looming shapes, one after another. Half of the sequences (causes) were predictive of an attention-getting reward (effect), and the other half were nonpredictive. The statistical complexity of predictive sequences was varied between conditions. We analyzed latencies of infants’ eye movements toward the reward location. Older infants yielded more anticipatory eye movements in predictive than non-predictive sequences. Effects of both infant age and complexity of causal sequences were observed. To qualitatively account for these findings, we formulated a Bayesian model based on generic priors favoring simple causal events coupled with noisy shape identification.