Other evidence suggests that two aspects of a discriminatory experience that can affect its stressfulness are the degree of ambiguity of the situation and the identity of the perpetrator. Limited evidence from the discrimination literature indicates that characteristics of the perpetrator can predict the degree of adverse impact with the effects being more negative when the perpetrator belongs to the same racial group as the target (Mays et al. 2007). The ambiguity surrounding an experience of discrimination can also be a determinant of its stressfulness, and greater attention should be given to assessing attributional ambiguity (Carter 2007). Several recent studies have noted stronger, more negative effects from subtle or ambiguous racial encounters than from blatant ones (Bennett et al. 2005; Stetler et al. 2006; Merritt et al. 2006). There may also be racial differences in the effects of ambiguity. A recent study of university students found that blacks experienced greater impairment in cognitive functioning when faced with ambiguous evidence of prejudice than when exposed to blatant prejudice (Salvatore and Shelton 2007). The opposite pattern was evident for whites. It may
