He pursued post-doctoral work at the University of Tübingen, Germany from which he obtained a Habilitation in 1986.

He then undertook further work with Serge Moscovici (in Paris) and Wolfgang Stroebe (in Tübingen).

He has been a Fellow at the Center for Advanced Study in the Behavioral Sciences, Stanford University.

He has published widely in the field of experimental social psychology.

His major topics of research have been: attribution theory, social cognition, social influence, stereotyping and intergroup relations, and intergroup conflict.