Abstract: The effect of reference point on individual and group decision - making under risk were studied based on prospect theory and social decision scheme. 300 subjects were asked to make choice among bets which were different in risk, and then to discuss with others in a three - person group until reaching a consensus . The results showed that, 1) subjects who had recent loss or even experiences prefered riskier bets than those who experienced recent gains in individual decision situation, but there was no difference between GAIN subjects 'preference and EVEN , s, 2) social context had significant effect only on the GAIN subject , s decision, 3) reference point effects were not found in group choice, but majority principle took a role instead.

Key words: reference point, risk decision -making, social decision scheme, majority principle