Table 1.

Conditions, analyses, individual oranges sizes, and group average sizes from two hypothetical trials in Experiment 1. In each trial of each condition, a separate group of eight oranges was generated for the left and right tree. For simplicity in this table, the sizes (diameter, in pixels) of the oranges in each tree are listed in order from smallest to largest. In the group condition, in which all eight oranges were presented and visible in each tree, we analyzed how well children and adults evaluated the average size in each tree—the group-via-group analysis. In this trial of the group condition, the right tree happens to have the larger average orange size (80 pixels). Note, however, that the largest orange in the left tree was larger than the smallest orange in the right tree. This illustrates how comparing a random pair of oranges in each tree would not always lead to a correct response about the groups. In the single condition, eight oranges were again generated for each tree, but only one randomly selected orange (in bold) was visible in each tree. The rest of the oranges (in italics) were not presented. We conducted two analyses—the single-via-single analysis and the group-via-subset analysis—on the same data from the single condition. The single-via-single analysis allowed us to evaluate sensitivity for comparing individual oranges. Here, the orange in the right tree (92 pixels) is the largest, and selecting the right tree leads to a correct answer in the single-via-single analysis. The group-via-subset analysis allowed us to determine what performance in the group condition would have been like had observers based their estimates on a single randomly selected orange in each tree. Here, accurately comparing this randomly selected pair of oranges would not have led to a correct response about the groups. Better performance in the group condition relative to this simulated performance in the group-via-subset analysis would mean that observers’ did not simply compare random pairs of oranges in the group condition

Condition	Analysis		Tree	Orange sizes (1–8)								Group Avg
GROUP	Group-via-group		L	68	68	72	72	76	76	82	82	74
			R	74	74	78	78	82	82	86	86	80
SINGLE	Single-via-Single	Group-via-Subset	L	86	86	90	90	94	94	98	98	92
			R	80	80	84	84	88	88	92	92	86