Supplementary Methods Weekly Pre-Survey The weekly pre-survey administered to obtain subject team choice and wager prefer- ences consisted of the following questions (with team names and spread appropriate to the upcoming game): S11 1. Based on your own knowledge do you believe that the Seahawks will cover the spread? To cover the spread, the Seahawks must win by at least 9 points. m Yes m No 2. Suppose you have a $7 bonus for donating to charity, with the potential to bet any amount from $0 to $7. Based on your answer to the previous question about which team would cover the spread, how much would you wager that your answer is correct? m $0 – The charity would get $7 regardless of whether Im right or wrong m $1 – If I’m right the charity would get $8, if I’m wrong the charity would get $6 m $2 – If I’m right the charity would get $9, if I’m wrong the charity would get $5 m $3 – If I’m right the charity would get $10, if I’m wrong the charity would get $4 m $4 – If I’m right the charity would get $11, if I’m wrong the charity would get $3 m $5 – If I’m right the charity would get $12, if I’m wrong the charity would get $2 m $6 – If I’m right the charity would get $13, if I’m wrong the charity would get $1 m $7 – If I’m right the charity would get $14, if I’m wrong the charity would get $0