Figure 1.

The within-subjects endowment effect task. The diagram represents schematically all the different conditions used in the scanning phase. Note that all the conditions were pseudorandomly intermixed. You_Sell condition (1st display): assign a minimum selling price for your £10 ticket (minimum payoff £0/maximum payoff £10; ticket EV £5). You_Buy condition (2nd display): assign a maximum buying price for £28 (minimum payoff £0/maximum payoff £28; ticket EV £14) ticket from the other deck. You_Evaluate condition (3rd display): state the price that this £10 ticket (minimum payoff £0/maximum payoff £10; ticket EV £5) is worth; this ticket will be not included in any transaction. Computer_Sells condition (4th display): the computer assigns on your behalf a minimum selling price for your £18 ticket (minimum payoff £0/maximum payoff £18; ticket EV £9). Computer_Buys condition (5th display): the computer assigns on your behalf a maximum buying price for £28 (minimum payoff £0/maximum payoff £28; ticket EV £14) ticket from the other deck. Subjects stated their prices by moving a cursor on a bar below the ticket. In the computer conditions a yellow box on the bar showed the computer prices and subjects were required to move the cursor inside the box. Note that the bar in the original experiment had a finer grained scale (5 ticks).