Purpose. Although most people perform around the level of chance in making credibility judgments, some researchers have hypothesized that high motivation and the provision of accurate feedback could lead to a higher accuracy rate. This study examined the influence of these factors on judgment accuracy and whether any improvement following feedback was related to social facilitation, a gradual incorporation of successful assessment strategies, or a re-evaluation of ‘tunnel vision’ decision-making.

Methods. Participants (N = 151) were randomly assigned to conditions according to motivation level (high/low) and feedback (accurate, inaccurate or none). They then judged the credibility of 12 videotaped speakers either lying or telling the truth about a personal experience.

Results. Highly motivated observers performed less accurately (M = 46.0%), but more confidently, than those in the low-motivation condition (M = 60.0%). Although there was no main effect of feedback, the provision of any feedback (accurate or inaccurate) served to diminish the motivational impairment effect. Further, high motivation was associated with a relatively low ‘hit’ rate and high ‘false-alarm’ rate. This suggested that in the absence of feedback the judgments of highly motivated participants were made through tunnel vision.

Conclusions. The results suggest that it is important for lie-catchers to monitor their motivation level to ensure that over-enthusiasm is not clouding their judgments. It may be useful for professionals engaged in deception detection to regularly discuss their judgments with colleagues as a form of feedback in order to re-evaluate their own decision-making strategies.