Cultural norms vary dramatically across social groups. Herewe use large scale data to examine the extent to which languageplays a role in shaping one such norm—the gender norm to as-sociate men with careers and women with family. We measurecross-cultural variability in this gender bias using previously-collected estimates from the Implicit Association Task (IAT; N= 663,709). We then try to predict bias variability by the waythat gender is encoded in language semantics and grammar.We quantify gender bias in semantics using word-embeddingmodels trained on different languages. Our data suggest thatthe linguistic encoding of gender predicts the degree of speak-ers’ gender bias in the IAT, pointing to a causal role for lan-guage in shaping gender norms.

What accounts for the vast diversity in the world’s languages?We explore one possibility: languages adapt to their linguis-tic environment (Linguistic Niche Hypothesis; Lupyan & Dale,2010). Recent studies have found support for this hypothesisthrough correlations between aspects of the environment andlinguistic structure. We synthesize this previous work and findthat languages spoken in cold, small regions tend to be morecomplex across a range of linguistic features. We also testa novel prediction of the Linguistic Niche Hypothesis by ex-amining the learnability of languages for first-language, childlearners.

Although natural languages are generally arbitrary in their mapping of forms to meanings, there are some detectable biases in these mappings. For example, longer words tend to refer to meanings that are more conceptually complex (what we refer to as a complexity bias; Lewis, Sugarman, & Frank, 2014). The origins of this bias remain an open question, however. One hypothesis is that this lexical regularity is the product of a complexity bias in individual speakers, and that it emerges in the lexicon over the course of language evolution. In the present work, we use an iterated learning paradigm to explore this proposal. Speakers learned labels of varying lengths for objects of varying complexity, and then were asked to recall the learned labels. We then presented the labels that participants produced to a new set of speakers, iterating this procedure across generations. The results suggest the presence of a complexity bias that guides language change but that interacts with pressures for simplicity

Does knowing certain words help children learn other words? We hypothesized that knowledge of more general (more superordinate) words at time1 would lead to faster vocabulary growth as measured through vocabulary checklists administered at later timepoints. We find that this is indeed the case. Children who have similar vocabularies at time1 , but differ in their productive knowledge of more general words such as “animal,” “picture,” and “get” go on to have different rates of word learning. Knowledge of more general words is associated with faster vocabulary growth, particularly of words semantically related to the superordinate terms they are reported to produce. This positive relationship between knowledge of more general words and word learning remains even when controlling for measures of verbal and nonverbal intelligence.

Young children acquire a wide range of linguistic and cognitive skills in the first three years of life. Decades of experimental work have established a solid empirical foundation for our understanding of cognitive development. But most experimental studies are limited in statistical power and focus on specific psychological constructs, thus making them unsuitable for describing developmental growth at scale. Here, we turned to meta-analyses of experimental research. We conducted a meta-meta-analysis to consolidate and integrate 23 meta-analyses compiled on MetaLab, a community-augmented meta-analysis platform. We found that most datasets can not meaningfully distinguish different functional forms for developmental change, but in those that could, there is great diversity in the best-fitting functional forms of the age model. We also evaluated the impact of a range of methodological factors. Overall, our work sheds light on the heterogeneous nature of developmental trajectories and the subtle interactions between research methods and experimental outcomes.

The study of mental representations of concepts has historically focused on the representations of the “average” person. Here, we shift away from this aggregate view and examine the principles of variability across people in conceptual representations. Using a database of millions of sketches by people worldwide, we ask what predicts whether people converge or diverge in their representations of a specific concept, and which kinds of concepts tend to be more or less variable. We find that larger and more dense populations tend to have less variable representations, and concepts high in valence and arousal tend to be less variable across people. Further, two countries tend to have people with more similar conceptual representations when they are linguistically, geographically, and culturally similar. Our work provides the first characterization of the principles of variability in shared meaning across a large, diverse sample of participants.

The emergence of language around a child’s first birthday isone of the greatest transformations in human development.Does this transition require a fundamental shift in the child’sknowledge or beliefs, or could it instead be attributable to moregradual changes in processing abilities? We present a simplemodel of cognitive performance that supports the second con-clusion. The premise of this model is that any cognitive op-eration requires multiple steps, each of which require sometime to complete and have some probability of failure. Weuse meta-analysis to estimate these parameters for two com-ponents of simple ostensive word learning: social cue use andword recognition. When combined in our model, these esti-mates suggest that learning should be very difficult for chil-dren younger than around a year, especially with gaze alone.This model takes a first step towards quantifying performancelimitations for cognitive development and may be broadly ap-plicable to other developmental changes.