PhD ceremony Ms. E. van der Werff: Growing environmental self-identity

PhD ceremony: Ms. E. van der Werff, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Growing environmental self-identity

Promotor(s): prof. E.M. Steg

Faculty: Behavioural and Social Sciences

Environmental problems are caused by human behaviour. Therefore, we need to understand which factors influence environmental behaviour. In this dissertation we studied whether environmental self-identity, that is, the extent to which you see yourself as an environmentally-friendly person, is an important predictor of environmental behaviour.

We found that the environmental self-identity predicts a wide range of pro-environmental actions, including different types of energy use and preference for sustainable products. As expected, the environmental self-identity was influenced by one’s biospheric values, and is therefore stable to some extent. Biospheric values even predicted environmental self-identity at a later moment in time and after manipulating environmental self-identity. Based on self-perception theory, we expected that the environmental self-identity can also be changed to some extent. Indeed, environmental self-identity changed when reminding people of their past environmental behaviour. When people realized that they often acted environmentally-friendly in the past, their environmental self-identity was strengthened which in turn promoted pro-environmental actions. When people realized they rarely acted environmentally-friendly in the past, their environmental self-identity was weakened and they were less likely to act pro-environmental. However, past behaviour only influenced environmental self-identity when the signaling strength of this behaviour was high, that is, when it concerned a range of rather different behaviours or when the behaviour was difficult and unique.

Finally, we found that people with a strong environmental self-identity are intrinsically motivated to act pro-environmental. A strong environmental self-identity resulted in a stronger obligation-based intrinsic motivation to act environmentally-friendly, which in turn encouraged pro-environmental actions.