Table 2. Effect of Set Size on Response Time and Sensitivity (d′) in Visual Search.

Task	Independent Variable	Log Transformed RT	d'
Conjunction Search	10	2.83±.02 [676 ms]	3.32±.03
	20	2.87±.02 [741 ms]	3.36±.03
	30	2.90±.02 [794 ms]	3.31±.03
	40	2.92±.02 [832 ms]	3.29±.03
	Set Size Effect	F(3,2003) = 165.72; p<.001	F(3.51) = 1.39; p>.05
	Target x Set Size Interaction	F(3,2003) = 33.5; p<.001
Spatial Configuration Search
	10	3.09±.03 [1230 ms]	3.32±.03
	20	3.20±.03 [1584 ms]	3.16±.03
	30	3.26±.03 [1820 ms]	3.12±.03
	40	3.29±.03 [1950 ms]	2.93±.04
	Set Size Effect	F(3,1571) = 399.55; p<.001	F(3,51) = 17.01; p<.001
	Target x Set Size Interaction	F(3,1571) = 9.91; p<.001

This table represents the main effect of set size from the ANOVA—a standard effect in visual search representing an increase in RT and a decrease in d′ with set size, which is an index of search difficulty. The effect of set size on RT was greater with the target absent than with the target present trials in both search tasks as indicated by the target x set size interaction. There was an effect of set size on d′ in the spatial configuration search task, but not in the conjunction search task, reflecting that the conjunction search task is an easier search than the spatial configuration search.