The aviation industry is a growing contributor to climate change, yet frequent flying has become a normalized behavior even among environmentally conscious individuals. This paradox, characterized by the attitude–behavior gap, reveals how social norms and cognitive dissonance sustain unsustainable travel practices. This thesis investigates how social norm interventions can be strategically designed to disrupt these dynamics and encourage sustainable alternatives among young professionals.
The research adopts a mixed-methods approach. Study 1 employed qualitative interviews to explore how individuals negotiate social expectations, experience conflicting emotions, and rationalize frequent flying. Findings highlighted the powerful influence of peer validation, the tension between environmental values and travel choices, and coping strategies such as justification and moral licensing. Study 2 tested these insights through a quantitative experiment with a between-subjects design, examining the effects of different social norm framings on emotional responses, perceived environmental impact, purchase intentions, and travel mode selection. Results showed that unsustainable static norm + unsustainable dynamic norm framings increased participants’ purchase intentions to choose trains over planes, triggers the negative feelings such as guilty, anxiety, frustration etc.
By integrating qualitative and quantitative evidence, this thesis demonstrates that how social norms can be reframed to shift travel choices. The findings advance understanding of how social norm reinforce the attitude–behavior gap and provide actionable insights for policymakers, organizations, and designers aiming to foster more sustainable mobility practices.

The fast fashion industry poses severe ethical and environmental challenges, yet consumer participation in this sector remains high. This thesis introduces the ‘stop and rethink’ mechanism as a novel behavioral intervention, grounded in dual-processing theory, which aims to disrupt automatic fast fashion consumption habits by leveraging the emotion of disgust. Across two studies, an online study (N=205) and a lab-study (N=200) participants were exposed to either ethically or environmentally disgusting fast fashion production narratives designed to elicit disgust and encourage reflective thinking. Results showed that both narrative types significantly increased negative emotional responses (e.g., disgust, fear, shame) and attention compared to a control narrative, indicating successful activation of a ‘stop’ response. In study 1, these narratives also triggered higher curiosity levels, suggesting activation of reflective, ‘rethink’ processes. However, study 2 revealed no significant changes in reflective thinking and no significant changes in sustainable behavior (e.g., reduced shopping, preference for slow fashion), highlighting the persistence of the intention-behavior gap. Thematic analyses revealed that narratives featuring post-production issues, such as overproduction, waste dumping, and harm to biodiversity, were most impactful in terms of attention. These findings suggest that while disgust can effectively interrupt fast fashion consumption at an emotional and cognitive level, additional strategies may be needed to translate this disruption into sustainable behavioral change.