Adults recognize that if event A predicts event B, intervening on A might generate B. Research suggests that although preschoolers draw this inference much like adults, toddlers do not (Bonawitz et. al, 2010). Here we look at whether toddlers ’ failure is domain-general (i.e., they lack an adultlike concept of causality that integrates prediction, intervention, and agency) or domain-specific (i.e., toddlers have trouble recognizing some physical processes as causal but might succeed with psychological events). We showed toddlers (24 months) a block moving into a base, after which an effect occurred; we then gave children the block and asked them to generate the effect. Toddlers performed the intervention and predicted the outcome when the effect was psychological (a puppet laughing) but, replicating previous studies, not when the effect was physical (a toy activating). Experiment 2 showed that this was not due to the relative saliency of the psychological effect.

Causation by omission is instantiated when an effect occurs from an absence, as in The absence of nicotine causes withdrawal or Not watering the plant caused it to wilt. The phenomenon has been viewed as an insurmountable problem for process theories of causation, which specify causation in terms of conserved quantities, like force, but not for theories that specify causation in terms of statistical or counterfactual dependencies. A new account of causation challenges these assumptions. According to the force theory, absences are causal when the removal of a force leads to an effect. Evidence in support of this account was found in 3 experiments in which people classified animations of complex causal chains involving force removal, as well as chains involving virtual forces, that is, forces that were anticipated but never realized. In a 4th experiment, the force theory’s ability to predict synonymy relationships between different types of causal expressions provided further evidence for this theory over dependency theories. The findings show not only how causation by omission can be grounded in the physical world but also why only certain absences, among the potentially infinite number of absences, are causal.

Meaning postulates and deference ∗