• Program Chair (1990), General Chair (1991)
    Optical Society of America Topical Meeting
    "Noninvasive Assessment of the Visual System"

  • Organizing Committee (1990)
    NATO Scientific Meeting
    "Advances in Understanding Visual Processes.
    Convergence of Neurophysiological
    and Psychophysical Evidence."
    Røros, Norway

  • Technical Program Committee (1992)
    Optical Society of America Topical Meeting
    "Advances in Color Vision"

  • Advisory Committee
    Optical Society of America Topical Meeting
    "Vision Science and its Applications" (1993-1994)

  • Session Organizer, "Human Color Vision"
    Intersociety Color Council Pan-Chromatic Conference
    Williamsburg, VA (1995)

  • International Scientific Program Committee
    l'Association Internationale de la Couleur meeting
    Kyoto, Japan 1997

  • Organizing Committee International Colour Vision Society, XVth Meeting
    Göttingen Germany (1999)

  • Scientific Program Committee
    l'Association Internationale de la Couleur meeting
    Rochester, NY (2001).

Joel and Vivianne with colleagues
from The Netherlands