Table A1.

Derivation of the predicted relative acquisition frequencies.

Reason	Reading phase	Choice phase				Choice and reading phases
		Priority heuristic			Expectation model	Priority heuristic						Expectation model
		r = 1	r = 2	r = 3		r = 1		r = 2		r = 3
						No.	%	No.	%	No.	%	No.	%
Minimum outcome	2	2	2	2	2	4	40	4	33.3	4	28.6	4	25
Maximum outcome	2	0	0	2	2	2	20	2	16.7	4	28.6	4	25
Probability of minimum outcome	2	0	2	2	2	2	20	4	33.3	4	28.6	4	25
Probability of maximum outcome	2	0	0	0	2	2	20	2	16.7	2	14.3	4	25
Total number of acquisitions	8	2	4	6	8	10		12		14		16

Example: There are eight acquisitions (two for each reason) in the reading phase. In the choice phase, for r = 1, the priority heuristic predicts two further acquisitions, of the minimum outcomes. Thus, across the reading and choice phases, there are a total of 10 acquisitions, in four of which minimum outcomes are examined. r = 1, one-reason choices; r = 2, two-reason choices; r = 3, three-reason choices.