Several occupations rely upon the ability to accurately and efficiently perform visual search. For example, radiologists must successfully identify abnormalities, and airport luggage screeners must recognize threatening items. By investigating various aspects of such searches, psychological research can reveal ways to improve search performance. We (Fleck, Samei, & Mitroff, in press) have recently focused on one specific influence that had previously been explored almost exclusively within the study of radiology: Satisfaction of Search (SOS), wherein the successful detection of one target can reduce detection of a second target in the same search array. To eliminate SOS errors, we must delineate the sources of the errors. Combined with our prior work, here we examine the specific roles of target heterogeneity and the decision-making component of target-distractor discrimination (i.e., how easy it is to determine whether a stimulus is a target or a distractor). In the current experiments, subjects searched arrays of line-drawn objects for targets of two different categories (tools and bottles) amongst several categories of distractor objects. On any given trial, there could be no targets, one target (either a tool or bottle), or two targets (both a tool and a bottle). The relative occurrence of these trial types varied across experiments. Compared to previous experiments that employed homogeneous targets and that required effortful evaluation to discriminate targets from distractors, the SOS effect was reduced here. That is, search accuracy for easily discriminable, heterogeneous objects was no worse for dual-target trials than for single-target trials. These results suggest that target heterogeneity and target-distractor discriminability may both play key roles in multiple target search accuracy.