This volume is the third volume of papers originating from the European Mathematical Psychology Group. Earlier volumes were: E. Degreef & J. van Buggenhaut (Eds.), Trends In Mathematical Psychology, Amsterdam, North-Holland Publ. Cy., 1984, and E.E. Roskam & R. Suck (Eds.), Progress in Mathematical Psychology, Amsterdam: Elsevier Science Publ. As the title indicates, this volume presents work in progress, which was reported in one of the recent annual meetings of the European Mathematical Psychology Group. The Group finds it worthwhile to disseminate this work, using a review process which is...