It has been shown that optimists tend to rely more on their prior expectations than sensory input when making decisions of an intense nature (Geers & Lassiter, 2002). We investigated the degree to which this tendency persists over a range of discrepancies between prior cues and actual stimuli. Eighty-seven participants were shown a subset of happy, sad and fearful pictures drawn from the Ekman facial expressions of emotion (Ekman & Oster, 1979). Each picture was preceded by a verbal cue indicating the impending emotional expression and intensity. The displayed pictures were either in agreement, slightly discrepant or very discrepant with the cue. Participants rated the extent to which they agreed/disagreed with the expectation cue. Probit signal detection models were used to produce acquiescence for each subject at each level of discrepancy. Correlation analysis was performed on acquiescence and dispositional optimism scores. There was a significant correlation between all acquiescence scores for levels of discrepancies and dispositional optimism. Optimism appears to be a trait associated with acquiescence. The apparent tendency of optimists to comply may be due to a cognitive style that relies on expectations, such that it takes them longer to recognise the extent of discrepancy between expectations and incoming information. Copyright © 2010 John Wiley & Sons, Ltd.