Can infants learn phonology in the lab? A meta-analytic answer

Abstract

Two of the key tasks facing the language-learning infant lie at the level of phonology: establishing which sounds are contrastive in the native inventory, and determining what their possible syllabic positions and permissible combinations (phonotactics) are. In 2002-2003, two theoretical proposals, one bearing on how infants can learn sounds (Maye, Werker, & Gerken, 2002) and the other on phonotactics (K. E. Chambers, Onishi, & Fisher, 2003), were put forward on the pages of Cognition, each supported by two laboratory experiments, wherein a group of infants was briefly exposed to a set of pseudo-words, and plausible phonological generalizations were tested in a subsequent phase. These two papers have received considerable attention from the general scientific community, and inspired a flurry of follow-up work. In the context of questions regarding the replicability of psychological science, the present work uses a meta-analytic approach to appraise extant empirical evidence for infant phonological learning in the laboratory. It is found that neither seminal finding (on learning sounds and learning phonotactics) holds up when close methodological replications are integrated, although less close methodological replications do provide some evidence in favor of the sound learning strand of work. Implications for authors and readers of this literature are drawn out. It would be desirable that additional mechanisms for phonological learning be explored, and that future infant laboratory work should employ paradigms that rely on constrained and unambiguous links between experimental exposure and measured infant behavior.

The profile of abstract rule learning in infancy: Meta‐analytic and experimental evidence

“…We would argue that this combination of approaches provides important benefits. Meta‐analyses, like big data approaches, allow conclusions to be evaluated at scales that cannot be reached in typical lab experiments (Bergmann & Cristia, ; Cristia, ; Tsuji, Bergmann, & Cristia, ), while lab experiments complement the meta‐analyses by permitting direct causal tests of their conclusions. Converging evidence of this type should increasingly be part of the researchers’ arsenal given concerns about replicability and statistical power in psychology, and infant research in particular.…”

“…For the remaining 17 records, we imputed the by‐subject correlation as the mean r , weighted by sample size. The by‐subject correlation was also used to calculate the standard error of each effect size, based on the equation in Cristia (); the standard error is used for weighting observations in meta‐regression analyses.…”

“…We aggregated and evaluated the evidence from 20 papers on how infants learn abstract repetition rules, hewing closely to procedures that have been successfully used to investigate other infant language phenomena (Bergmann & Cristia, ; Bergmann et al., ; Lewis et al., submitted; Tsuji & Cristia, ), including studies on artificial grammar learning (Black & Bergmann, ; Cristia, ). We followed the ‘Preferred Reporting Items for Systematic Reviews and Meta‐Analyses’ (PRISMA) statement (Moher, Liberati, Tetzlaff, Altmann, & PRISMA Group, ) in preparing this meta‐analysis.…”