In the current investigation, we modified the high Go low No-Go Sustained Attention to Response Task (SART) by replacing the single response on Go trials with a dual response (dual response SART or DR SART). In three experiments a total of 80 participants completed the SART and versions of the DR SART in which response probabilities varied from 50-50, through 70-30 to 90-10. The probability of No-Go withhold stimuli was .11 in all experiments. Using a dynamic utility based model proposed by Peebles and Bothell (2004) we predicted that the 50-50 DR-SART would dramatically reduce commission errors. Additionally, the model predicted that the probability of commission errors to be an increasing function of response frequency. Both predictions were confirmed. Although the increasing rate of commission errors with response probability can also be accommodated by the rationale originally proposed for the SART by its creators (Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) the fact that the current DR SART results and SART findings in general can be accommodated by a utility model without need for any attention processes is a challenge to views that ascribe commission errors to lapses of sustained attention.