A meta-analysis of syntactic priming in language production

We performed an exhaustive meta-analysis of 73 peer-reviewed journal articles on syntactic priming from the seminal Bock (1986) paper through 2013. Extracting the effect size for each experiment and condition, where the effect size is the log odds ratio of the frequency of the primed structure X to the frequency of the unprimed structure Y, we found a robust effect of syntactic priming with an average weighted odds ratio of 1.67 when there is no lexical overlap and 3.26 when there is. That is, a construction X which occurs 50% of the time in the absence of priming would occur 63% if primed without lexical repetition and 77% of the time if primed with lexical repetition. The syntactic priming effect is robust across several different construction types and languages, and we found strong effects of lexical overlap on the size of the priming effect as well as interactions between lexical repetition and temporal lag and between lexical repetition and whether the priming occurred within or across languages. We also analyzed the distribution of p-values across experiments in order to estimate the average statistical power of experiments in our sample and to assess publication bias. Analyzing a subset of experiments in which the primary result of interest is whether a particular structure showed a priming effect, we did not find evidence of major p-hacking and the studies appear to have acceptable statistical power: 82%. However, analyzing a subset of experiments that focus not just on whether syntactic priming exists but on how syntactic priming is moderated by other variables (such as repetition of words in prime and target, the location of the testing room, and the memory of the speaker), we found that such studies are, on average, underpowered with estimated average power of 53%. Using a subset of 45 papers from our sample for which we received raw data, we estimated subject and item variation and give recommendations for appropriate sample size for future syntactic priming studies. (C) 2016 Elsevier Inc. All rights reserved.