A Developmental Shift in Judgments About Relative Impossibility

• In Event: How Children Judge the Possibility of Improbable and Impossible Events

Abstract

Although people readily distinguish between events that are possible and those which are impossible, they view some impossibilities as more impossible than others. For instance, adults think it is more impossible to levitate a bowling ball than a basketball (Shtulman & Morgan, 2016). When making these judgements, adults may draw on real-world causal knowledge and apply this knowledge (e.g., about physics or biology) to impossible events. However, when children make possibility judgements, they may use a shallower approach based on similarity between the before and after states of the impossible event they are presented with (Goulding & Friedman, 2021). In this research, we provide the first demonstration that young children also distinguish between degrees of impossibility. We also investigate whether children and adults differ in how they assess the relative impossibility of impossible events.

We tested 4–7-year-olds (N = 58 so far) and adults (N =2 11). Participants were told a wizard wanted to turn a target object (e.g., a wall clock) into either of the two related objects: one that matched the perceptual appearance of the object (e.g., a plate) and one that matched the category of the target object (e.g., a grandfather clock). Participants were either asked which spell was easier, or which spell was harder (manipulated between-subjects). This repeated for a total of 4 magical transformation spells: wall clock into a plate (perceptual) or grandfather clock (categorical), a flashlight into a microphone (perceptual) or larger flashlight (categorical), baguette into a baseball bat (perceptual) or sliced bread (categorical), and an apple into a tennis ball (perceptual) or banana (categorical).

Figure 1 shows children’s and adults’ responses to each item. A generalized estimating equation model with the predictors age-group (children, adults), judgement (easy, hard), and item (clock, flashlight, baguette, apple) revealed multiple significant effects including a 3-way interaction between group, condition, and item: F(3) = 4.44, p = 004. To simplify the analysis, we conducted separate age-group x judgement analyses for each item. For all items except the apple, these revealed a significant interaction between age-group and condition: clock, p < .001; flashlight, p = < .001; baguette, p = .030; apple, p = 0.576. The interactions resulted because children were more likely to select the perceptual match when rating the ease of transformation, whereas this effect was either reduced or reversed in adults. That is, children were more likely than adult to base judgments about the relative impossibility of transformations on perceptual similarity.

Together, these findings illustrate a difference between how children and adults make judgements when grading the impossibility of multiple impossible events. Children consistently affirmed that a perceptual transformation was easier, indicating that children are likely comparing the visual similarity of objects and using this information to inform their judgement whereas adults showed a varied pattern of judgments across the different item sets. As such, it is likely that children assessed the relative impossibility of transformations by considering visual similarity, and not by drawing on real-world causal knowledge.

Authors

• Zoe Tipper, University of Waterloo
  Presenting Author

• Ori Friedman, University of Waterloo