I am currently a Distinguished Professor of the Graduate School in the Berkeley School of Education at the University of California, Berkeley. My research focuses on the interplay between cultural and cognitive processes in the reproduction and alteration of ideas in human communities. Using mathematics as an illustrative domain for inquiry, I have situated my work in the collective practices of daily life in remote parts of Papua New Guinea (economic exchange, schooling), urban and rural areas of northeastern Brazil (candy selling, straw weaving), and elementary and middle school classrooms in the United States (most recently collective practices in classroom communities). My prior book and monograph include Culture and Cognitive Development: Studies in Mathematical Understanding (1991), Social Processes in Early Number Development (with S. Guberman and M. Gearhart, 1987). My recent book, for which this website provides visual support, is Cultural Development of Mathematical Ideas: Papua New Guinea Studies (2012). Some of the publications linked to these and other of my projects can be downloaded from the publications page.

Acknowledgements. In my work in Oksapmin communities in Papua New Guinea on which the book is based (three visits in 1978, 1980, 2001), I've benefitted from the help and support of many people and institutions. Many are from Oksapmin communities, and many of their images are captured in the Photo Gallery and Videos pages. Other people that supported my work in Oksapmin included colleagues (the late Tom Moylan (in 1978, 1980) and Virginia Guilford (in 1978)), former graduate students (Indigo Esmonde and Cliff McIntosh in 2001), my son Josh (in 2001), and Maryl Gearhart, my partner in life (in 1980). In 1978 and 1980, David Lancy (1978) and Randy Souviney (1980) were Principal Research Officers linked to the PNG Ministry of Education, and they facilitated my visits during those years. In 2001, the late Rex Matang and Wilfred Kaleva had established the Glen Lean Ethnomatematics Centre at the University of Goroka, and they faciltated my 2001 visit. Funding for the fieldwork over the years of fieldwork and support while writing has come from The Spencer Foundation, the former National Institute of Education, the Center for Advanced Studies in the Behavioral Sciences, the Bellagio Center (the Rockefeller Foundation), and Wenner-Gren. The book that this website supports could not have been completed without the support and help of so many.

A more recent visit and current work. In June, 2014, eighteen months after the book was first published, I returned to Oksapmin with my son, Josh (now a senior computer scientist at Meta), and Kenton de Kirby, a former PhD student working with me at UC Berkeley (who completed his dissertation (2017)). In addition to visiting, we conducted pilot projects that included a follow-up study on the use of the 27-body part counting system in schools as well as an analysis of a One Laptop per Child Program first implemented in 2011 (I'm grateful to David Leeming for support information and contacts he provided that facilitated the OLPC project). With Kenton, I completed an analysis of the OLPC project that appeared in Anthropology & Education Quarterly (see Publication Page), and we're now working on a follow-up to the use of the body system (in schools). Josh is now (2020) chief research scientist at Sophos, engaged with research that advances the use of machine learning to support malware detection.