Four experiments are reported in which the effects of peripheral cues on visual orienting were investigated. In the luminance condition, the cues consisted of a peripheral change in stimulus luminance. In the isoluminance condition, the cues consisted of an isoluminant color change, using the transient tritanopic technique. In Experiments 1 and 2, it was found that peripheral luminance cues captured attention, whereas peripheral isoluminance cues did not. In Experiments 3 and 4, the participants detected a peripheral target that was also isoluminant with the background. Under these conditions, it was found that both luminance and isoluminance cues captured attention. The results are discussed in terms of the roles of the dorsal and ventral streams in visual orienting, and it is concluded that our findings provide partial support for the contingent involuntary orienting hypothesis of C. Folk and colleagues.