Poster #11 - The Role of Counterexamples in Judgments About Generic Statements

• In Event: Poster Session 07

Abstract

Generic statements (e.g., “Ducks lay eggs”) provide generalizations about kinds and can remain true, even in the face of exceptions (e.g., male ducks don’t lay eggs). Although past research has focused on the positive evidence that justifies a generic, little work has explored the role of counterevidence—that is, category members that are exceptions. In a series of 6 experiments, this work aims to understand how different types of counterexamples may differentially influence whether generic statements are accepted. In Studies 1-5, adults (n=678) and children ages 5-11 (n=113) were asked to judge the truth of generic statements about a series of different fictitious animal kinds (e.g., “Feps have round ears”). Accompanying each statement was a set of 6 kind members, some of which displayed the target property (e.g., round ears), and others of which displayed either an alternative property (e.g., pointy ears), or an absence of the property (e.g., no ears). Based on theoretical claims by Leslie (2008), we hypothesized that counterexamples with an alternative property would undermine support for the generic, as compared to counterexamples with the absence of a property.

Studies 1-4 found that adults were significantly less likely to endorse generic statements when counterexamples displayed an alternative property than when they displayed an absence of the property. This result was obtained whether alternative properties were salient or non-salient (Figure 1). Importantly, Study 5 revealed comparable findings with children ages 5-11, who endorsed generic statements more often when presented absence counterexamples (M=0.56) than either low salience (M=0.47; p=.002) or high salience alternative properties (M=0.46; p<.001). These findings provide the first evidence that children and adults attend to counterexamples when making judgments about generic statements, interpret alternative counterexamples to be stronger counterevidence than absence counterexamples, and do not use the salience of alternative properties to determine the strength of alternative counterexamples.

Study 6 was a forced-choice task, providing a direct contrast between different kinds of counterexamples. On a series of 14 trials, adults (n=120) were presented with a generic statement (e.g., “Wugs have blue horns”) and were asked to select which of two animal kinds was referenced. Six animals were provided for each category, with a set number displaying the target property for each. For one sample, the counterexamples displayed an alternative to the target property (e.g., red horns instead of blue horns); for the other, the counterexamples displayed an absence of the target property (e.g., no horns instead of blue horns) (Figure 2). Adults were significantly more likely to select the samples with absence than alternative counterexamples (94% vs. 6% of trials; p<.001). In an ongoing study (n=90 participants, with 3 participants needed to reach desired n in each order), children ages 5-10 are also more likely to select animal samples with absence than alternative counterexamples (75% vs. 25% of trials), with this pattern strengthening with age (p<.001).

These findings suggest that harmful generalizations expressed with generics may be best counteracted by counterexamples that display an alternative property instead of the mere absence of the target property.

Authors

• Ella Genevieve Simmons, University of Michigan - Ann Arbor
  Presenting Author

• Susan A Gelman, University of Michigan - Ann Arbor