Objects with emotional or motivational value are thought to benefit from facilitated perceptual processing. However, previous studies that have combined emotional variables with perceptual tests generally have relied on stimuli with well-established emotional value (e.g., expressive and neutral faces), ensuring that the manipulation of emotional value was accompanied by a change in perceptual content. This dissertation contains a set of experiments that combine an aversive conditioning paradigm with tests of perceptual detection and discrimination, so the perceptual characteristics of the emotional and non-emotional stimuli can be controlled and counterbalanced. Moreover, the stimulus space is designed to allow the effects of emotional value and emotional ambiguity to be deconfounded. Behavioral results indicate that perceptual detection and discrimination abilities are improved for stimuli with emotional value, however the effect has a delayed onset and only appears in the second half of the experiment. Emotional value is associated with a decreased amplitude for early visually-evoked ERPs (P1 window), and sLORETA source-estimation suggests that this P1 amplitude reduction is caused by increased activity in orbitofrontal cortex and ventromedial PFC. The P1 effect occurs in the first half of the experiment, but not the second, suggesting that it may be a reinforcement learning signal used to drive perceptual reorganization. The final experiment explores whether conditioning-induced changes to target detection would generalize to novel stimuli and how the categorical structure of the stimulus space can impact the effects of emotion.