I specialize in semantic typology, the crosslinguistic study of universals and variation in semantic categorization. Semantic typologists investigate how languages vary and resemble one another in how they represent reality. I have conducted extensive research on the semantic typology of representations of space, time, events, and causality and on the Linguistic Relativity Hypothesis, according to which language-specificity in semantics may be a shaping factor in culture-specificity in nonverbal cognition.
Since 2007, I have been directing three large-scale collaborative research projects on these topics with the support of the National Science Foundation. Cumulatively, these projects have brought together some 60 researchers from around the world to date collecting data and jointly advancing analyses. I also founded the Semantic Typology Lab at the University at Buffalo, which has been a forum and incubator for student and faculty research since 2008. The Semantic Typology Lab has to date been the home to nine past and present doctoral dissertation research projects and has contributed to others beside these. Five of these projects have been supported by Doctoral Dissertation Research Improvement Grants awarded by the National Science Foundation. Of these, four have involved field research on indigenous languages of Mexico. I'm also a Mesoamericanist myself and have been conducting field research on Yucatec Maya since 1991.
An overarching theme in my research is the role of culture in cognition. I view this interest as part of a broader empiricist turn in the cognitive sciences. This paradigm shift or paradigm maturation process has been leading the field slowly away from its rationalist beginnings, which were heavily invested in assumptions of innateness, symbolic encoding, and modularity, toward a "Cognitive Science 2.0" that embraces individual and cultural variation and brain plasticity. A closely related line of inquiry, which I have been pursuing since the days of my own doctoral research, is the emergence of functional categories in the languages of the world. Across space and time, unrelated languages have been evolving similar functional categories. Yet, the amount of observable crosslinguistic variation in the grammaticalization of such categories discourages simplistic innatist explanations. I have been developing an evolutionary approach that attributes crosslinguistic similarities in functional category systems to processes of cultural evolution responding to pressures of optimizing communication.