I am broadly interested in understanding the psychological mechanisms underlying large scale socio-cultural phenomena. My work has primarily focused on language as a particularly interesting and important case study of socio-cultural regularities. Using language, I have sought to understand how cognitive and pragmatic pressures can lead to patterns in behavior at the level of individuals, and over time, how these pressures can lead to law-like regularities at the level of social groups. I am also interested in the role of development in these dynamics. Below are more detailed descriptions about four areas of my research (see papers for full publication list).
In my postdoc, I have been working on two projects exploring cross-cultural semantics. In one project with James Evans, I have been exploring word-embeddings from English text written by speakers of non-English first languages. With Gary Lupyan, I have been examining the Google Draw dataset to uncover cross-cultural variability in meaning representations (Lewis & Lupyan, 2018).
Left: The prototypical “bread” drawing by country, calculated as the drawing with the smallest average pairwise distance to other drawings from the same country.
As a case study of how linguistic regularities emerge, I have studied the bias for languages and people to tend to use longer words to refer to more complex concepts, or a "complexity bias" (Lewis & Frank, 2016a; Lewis & Frank, 2016b; Lewis & Frank, 2016c; Lewis & Frank, 2015; Lewis & Frank, 2014).
Left: (a) Schema of word mapping task (b) Artificial “geon” stimuli. (c, d) Experimental results from a task in which participants were asked to map a novel word of varying length to one of two possible referents.
How do children identify the referent of a word in context, and how do they generalize that meaning to new situations (Lewis & Frank, 2013b)? I have been particularly interested in understanding the bias for children to assume a novel word maps onto to a novel concept ("mutual exclusivity" bias; Lewis & Frank, in prep.; Lewis & Frank, 2013a). In another project (Metalab), I have explored how we can use meta-analytic data to develop a meta-theory of language acquistion (Lewis, Braginsky, Tsuji, Bergmann, Piccinini, Cristia, & Frank, M., under review; Bergmann, Tsuji, Piccinini, Lewis, Braginsky, Frank, & Cristia, in press).
Left: Three left panels show three possible systems-level theories of language acquisition. Right panel shows the empirical trajectory of different language skills, as measured through meta-analysis.