Logic in Infants The ability of infants to perform disjunctive syllogism Allison Hyland, 2012 Supervised by Dr. Susan Carey and Shilpa Mody

Presentation Overview Description of Disjunctive Syllogism Review of previous studies Methods of our study Results Implications Potential future studies Questions

Implications of this research Chrysippus Dog Anecdote How can we do this? What kinds of symbols are available in the mind? What computational tools and devices do we have access to?

Disjunctive Syllogism Simple argument form Process of elimination ◦ A or B ◦ Not B ◦ Must be A Also called modus tollendo ponens Mutually Exclusive (only one possibility can be correct)

Previous Studies Halberda, 2003: The development of a word-learning strategy Looking time study

Results

Still leaves the question: ◦ Did the infants use Disjunctive Syllogism (logic) or simply match novel to novel without performing logic (N3C) ◦ Why did 14 month olds exhibit opposite behavior?

Previous Studies Halberda, 2006: Is this a dax which I see before me? In response to unaddressed issues of previous study Another looking time study with more stringent statistical techniques Done first on adults to indicate if his procedure was efficient

Results: General task success

Results: double checks

Halberda, 2006-cont. Did similar procedure with preschool- aged children Preferential pointing method and quantitative evaluation of number of double-checks

Results: general task success

Results: double checking success

Previous Studies Disjunctive syllogism just for word-learning? Or domain general? Waxman & Booth, 2000: Principles that are invoked during the acquisition of words but not facts Tested whether children can map novel words to novel objects/novel facts to novel objects AND whether they could extend the significance of these novel objects to similar objects in each case

Results

Previous Studies Domain Specificity? Spiegel, Yamaguchi, Heverly-Fitt, Halberda, 2009: Children’s use of logical inference in mapping novel voices to novel characters Preferential pointing technique in children

Results

Still leaves the question: ◦ When do children develop the ability to perform disjunctive syllogism in simple, A or B situations?

Our Study We are investigating whether infants can reason about possibilities using the process of elimination. They will see that a toy is being hidden in one of two locations, but will not know which one it is in. Can they use visual or verbal information about where the object is not to determine where it is? How will we do this?

Methods: Based on Previous Study Call, 2004: Inferences about the location of food in the great apes 2 variables: ◦ Visual clue as to location of where food was/was not ◦ Auditory clue as to location of where food was/was not

Results suggests inferential reasoning

Our Methods and Procedure Subject Physical set up 2 Practice Trials 4 Test Trials Types of Evidence Counterbalancing of Conditions: ◦ PL, PR, VL, VR

What does this look like?

Results

Results

Conclusions so far Not very many children Tentatively our data supports that children aged between 23 and 24 months can successfully perform disjunctive syllogism

Implications Results at 23 months Baseline and definitive age at which children can perform this simple logic

Potential Future Studies Younger Children Verbal Cues

Questions?

References Call, Josep. (2004). Inferences about the location of food in the great apes (pan paniscus, pan troglodytes, gorilla gorilla, and pongo pygmaeus). Journal of Comparative Psychology, 118(2), Halberda, Justin. (2003). The development of a word-learning strategy. Cognition, 87(2003), B23-B34. Halberda, Justin. (2006). Is this a dax which I see before me? Use of the logical argument disjunctive syllogism supports word-learning in children and adults. Cognitive Psychology, 53(2006), Spiegel, Chad A., Yamaguchi, Mariko, Heverly-Fitt, Sara & Halberda, Justin. (2009). Children’s use of logical inference in mapping novel voices to novel characters. Poster presented at Society for Research in Child Development, Denver, CO. Waxman, S. & Booth, A. (2000). Principals that are invoked during the acquisition of words but not facts. Cognition, 77(2),