Affective factors such as anxiety, confidence, and motivation impair and enhance mental rotation performance. Yet how these variables affect visualization, manipulation, and decision making on mental rotation tasks remains largely unknown, perhaps in part because analyses are generally concerned with overall accuracy and reaction time (RT) without decomposing the stages of processing. Here we extend existing research by using drift diffusion modeling (DDM) to decompose performance on a mental rotation task (MRT) into separate processing components (i.e., encoding, rotation, and decision making). 100 adult participants performed a 2AFC MRT “as quickly and as accurately as possible” (96 trials). Throughout the task, participants rated their levels of state anxiety, confidence, and motivation associated with the previous trial. In the primary analyses, we were interested in the dissociation between rotational and decision stage processes. We regressed drift rates (‘v’ – the speed of information processing of MRT stimuli) and decision thresholds (‘a’ – the amount of evidence accumulated before committing to a same/different decision) onto participants’ ratings of state anxiety, confidence, and motivation (controlling for trait anxiety). These analyses revealed that whereas higher state anxiety was associated with decreased drift rates, higher confidence and motivation were associated with increased drift rates. Moreover, higher confidence was associated with increased decision thresholds. These findings suggest that although all affective factors impacted the speed of information processing, only confidence affected the amount of evidence accumulation. Our findings are in line with others who have argued that state anxiety disrupts information processing during mental rotation. Our findings also demonstrate that confidence and motivation, typically overlooked in the literature, may play a similar role in affecting information processing efficiency. Finally, our findings point to a specific role for confidence in determining the amount of effort contributed to the decision stage processes in mental rotation.