Preference reversals between joint and separate evaluations of options: A review and theoretical analysis
Psychological Bulletin (1999) - Comment
doi: 10.1037/0033-2909.125.5.576  issn: 0033-2909  issn: 1939-1455 

Chrisopher K. Hsee, George F. Loewenstein, Sally Blount, Max H. Bazerman