What causes patterns of functional specialization in the human brain? Are such responses built into our genetic inheritance, or do they arise through learning and experience with environmental structure? The nature and extent of diversity in human cognition hinges upon answers to these questions. I will discuss new work suggesting that the functional profiles of different cortical regions are jointly constrained by their long-range anatomical connectivity and by learning and experience. At a coarse scale this arrangement produces homologies across individuals with little effect of experience, but at a finer scale, substantial individual variability can be observed. I will support these arguments with reference to new brain imaging, computational modeling, and patient studies of semantic memory—the form of memory that supports knowledge about the meanings of words and objects. The convergence of methods suggests a new account of semantic representation that reconciles long-standing theoretical disputes.
Psychology suffers from the problem of studying a narrow database: most research is conducted on samples that are from Western, Educated, Industrialized, Rich, and Democratic societies. The problem is both that many psychological phenomena appear differently across cultures, and that WEIRD samples are psychological outliers on many dimensions. I will review some evidence that reveals the extent of cultural diversity in various psychological processes, and will discuss some implications. In particular, the WEIRD people problem intersects with a recent concern of a replicability crisis in psychology because failed replications conducted in other cultures might indicate boundary conditions for an effect, rather than a problem with internal validity. Moreover, as one solution to the replicability crisis is to collect larger sample sizes this has the unwanted consequence of further incentivizing the reliance on cheap convenience samples, which would exacerbate the WEIRD people problem. Implications and recommendations will be discussed.