<p>Characterized by heightened sensitivity to subtle stimuli and linked to brain regions involved in visual and attentional processing, the influence of sensory processing sensitivity (SPS) on perceptual performance remains unclear. This study investigated how SPS influences visual perception and metacognitive awareness using an orientation discrimination task. After an initial staircase procedure to determine individual thresholds, participants categorized upright stimuli and tilted stimuli which near the customized thresholds. SPS and Neuroticism were assessed through questionnaires, with Neuroticism as a confounding variable. Data analyses were carried out on a final sample of 118 participants. Results showed no correlation between SPS and orientation discrimination threshold. Nevertheless, individuals with higher SPS, likely due to high levels of Neuroticism, demonstrated reduced accuracy for upright stimuli. Additionally, high SPS was associated with slower responses when misidentifying upright stimuli as tilted, even after controlling for Neuroticism, suggesting heightened cautious and deliberate processing under uncertainty. Furthermore, higher SPS predicted reduced metacognitive awareness of errors, suggesting overconfidence in accuracy after deliberation, while Neuroticism showed no such effect. These findings suggest that caution should be exercised when linking higher SPS to general superior perceptual discrimination abilities and highlight the distinct influences of SPS and Neuroticism on visual perception and metacognitive awareness.</p>