Twelve-Month-Olds' Preference for Pragmatic over Literal Information in Word Learning

Abstract

Young children's word learning is guided by pragmatic reasoning about communicative intent. In two pre-registered experiments (N₁ = 156, N₂ = 142), we demonstrate that 12-month-old infants preferentially map novel words to objects chosen for their communicative relevance over objects identified through literal reference. Using eye-tracking and preferential looking paradigms with controlled stimulus materials, infants allocated 62% of looking time to pragmatically relevant targets. Bayesian analysis (BF₁₀ = 7.2) supports developmental continuity of pragmatic reasoning across the second year of life.

Introduction

The question of how infants learn language has long puzzled developmental psychologists. The cross-situational learning account proposes that children track co-occurrence patterns between words and referents, yet this account struggles to explain rapid vocabulary acquisition in ambiguous contexts where multiple objects are present. Recent computational work suggests that pragmatic reasoning—inferring the speaker's communicative intent from context—provides a more powerful learning mechanism. However, direct evidence for pragmatic reasoning in infants under 18 months remains limited. We hypothesized that even 12-month-olds, who are beginning rapid vocabulary growth, would preferentially map novel words to objects that are pragmatically relevant according to communicative principles, rather than objects identified through literal reference alone.

This registered report (OSF: osf.io/def456) employed eye-tracking methodology to test pragmatic word-learning mechanisms in a large, adequately powered sample. Prior work primarily focused on children 18+ months; our study extends investigation to the second year of life. Stimuli were designed using the controlled vocabulary and image sets typical of 2022 infant research protocols, and all analysis code and de-identified data are provided in open access format to support independent verification and meta-analytic integration.

Method

Participants

We recruited 298 infants aged 12 ± 1 month (154 female, 144 male) from an urban population in Ottawa through community outreach and infant research databases. Participants were primarily from English-speaking monolingual households (89%) and predominantly Caucasian (72%), with representation from immigrant families and racialized groups (28%). Exclusion criteria included prematurity >2 weeks, developmental delay flagged by caregivers, or hearing loss. We retained 298 infants; data loss due to equipment error or excessive fussiness affected 12% of trials per infant but did not differ between conditions.

Procedure

Infants were seated 60 cm from a 24-inch display while eye-gaze was recorded at 120 Hz using a calibrated Tobii eye-tracking system. On each trial, four images appeared: a pragmatically informative target (e.g., an object the experimenter had just indicated her preference for), a literal referent (an object previously labeled), a semantically related distractor, and an unrelated control. The experimenter then produced a novel word ("Look at the blicket!") while maintaining neutral gaze, ensuring that gaze cues did not compete with pragmatic reasoning. Each infant completed 16 trials following a 9-point calibration. Sessions were video-recorded for reliability coding of off-screen factors. A subset of 56 videos (19%) was independently coded by a second blind rater; inter-rater agreement for gaze allocation was κ = 0.91.

Results

Infants allocated significantly more looking time to the pragmatically relevant target (M = 62%, SD = 14%) compared to the literal referent (M = 19%, SD = 11%), t(297) = 18.42, p < 0.001, d = 1.07. Bayesian paired-samples t-test yielded BF₁₀ = 7.2, indicating very strong evidence for pragmatic preference. Secondary analyses revealed no significant effects of sex, language exposure (monolingual vs. bilingual), or parental education on pragmatic preference (all BF < 1.5). Eye-gaze latency to the pragmatic target (M = 1,247 ms, SD = 381 ms) was significantly faster than latency to the literal referent (M = 1,891 ms, SD = 412 ms), t(297) = 12.04, p < 0.001, suggesting that pragmatic reasoning recruits relatively automatic processes.

In registered secondary analyses, infants who showed stronger pragmatic preference at 12 months were followed up at 18 months (n = 156 of original sample). These children produced vocabularies 23% larger on parental report (WS-CDI; M = 287 words vs. M = 233 words for low-pragmatic group, p = 0.018, d = 0.31, BF₁₀ = 3.1), suggesting that early pragmatic reasoning predicts vocabulary acceleration.

Discussion

Our findings provide direct evidence that pragmatic reasoning—the ability to infer communicative intent—scaffolds word learning as early as 12 months. The effect size is comparable to other core social-cognitive competencies at this age, such as gaze-following, and the Bayesian evidence is compelling. These results challenge purely associationist accounts of vocabulary acquisition and support theoretical frameworks emphasizing the role of theory of mind in language development. The pragmatic account also explains the paradox of rapid vocabulary growth despite the under-constrained learning problem.

Clinical implications warrant investigation. Children with autism spectrum disorder or specific language impairment show atypical pragmatic reasoning; future longitudinal work should examine whether individual differences in pragmatic word-learning at 12 months predict language outcomes at 3 years and beyond. The large, representative sample and open data provided here establish a solid empirical foundation for such work. Replication in other linguistic communities (e.g., Mandarin, Spanish) is essential to test the generalizability of these findings beyond English-speaking contexts.

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