Laura Molteni

Background: Contemporary society faces significant challenges that can lead to stress-induced tunnel vision. Positive affect can counteract these effects by expanding humans’ attentional scope, potentially promoting resilience and creativity. This preregistered triple-blind study investigated the role of endogenous opioids in mediating attentional broadening following reward receipt. Methods: Using a placebo-controlled crossover design, 40 volunteers underwent two sessions separated by at least 1 week, receiving either 50 mg of naltrexone or a placebo. Participants completed a Navon letters task designed to contrast the effects of reward receipt versus reward anticipation on attentional scope. Results: As predicted, our results show that the attentional broadening observed after reward receipt under placebo was eliminated when opioid receptors were blocked. Naltrexone did not result in blunted reward anticipation effects on task performance or attentional narrowing. Conclusions: This study highlights the role of endogenous opioids in attentional breadth and their potential for cognitive flexibility and resilience through natural positive experiences, with potential implications for mental health and stress management.