We investigate the effects of decision aid reliability and pressure to perform on decision aid reliance. A total of 403 students took part in a four (pressures to perform: one through four) by five (decision aid reliability: 50%, 60%, 70%, 80% and 90%) between-participants experiment. We test two competing models of decision aid reliance behavior: pressure-induced rationality and pressure arousal theory. Additionally, we introduce a general model of reliance on a decision aid. We find that pressure arousal theory predominantly explains decision aid reliance behavior at all but the highest level of decision aid reliability tested in this study (90%). Our results indicate that there are reliance peaks across the reliability levels as more pressure to perform is applied, and that continually increasing pressures can eventually lead to decreased, rather than increased, reliance.