Roy D'Andrade (1995) sees the history of cognitive anthropology proper as divisible into four phases. The first began in the 1950s with the explicit formulation of culture as knowledge by anthropologists such as Ward Goodenough and Anthony Wallace. From the late 1950s through the mid-1960s, attention focused on categorization, componential analysis (a technique borrowed from structuralist linguistics), and native or folk systems of knowledge (ethnoscience e.g., ethnobotany, ethnolinguistics and so on), as well as discoveries in patterns of color naming by Brent Berlin and Paul Kay. During the 1950s and 1960s, most of the work in cognitive anthropology was carried out at Yale, University of Pennsylvania, Stanford, Berkeley, University of California, Irvine, and the Harvard Department of Social Relations. The third phase looked at types of categories (Eleanor Rosch) and cultural models, drawing on schema theory, linguistic work on metaphor (George Lakoff, Mark Johnson). The current phase, beginning in the 1990s, has seen more focus on the problem of how cultural models are shared and distributed, as well as on motivation, with significant work taking place at UC San Diego, UCLA, UC Berkeley, University of Connecticut, and Australian National University, among others.