Can reflective diary-writing increase sufficiency-oriented consumption? A longitudinal intervention addressing the role of basic psychological needs, subjective well-being, and time affluence

Sufficiency is a sustainability strategy aiming for (1) a decrease in absolute resource consumption on individual and societal levels and (2) for socio-ecological justice and the fair distribution of costs and benefits of resource use to meet every human’s basic needs. This study examined a longitudinal intervention to foster individual sufficiency orientation (i.e., a multidimensional construct including both attitudes towards sufficiency sustainability strategy and corresponding behavioral intentions). We recruited N=252 participants who participated in a one-week reflective diary-intervention to increase sufficiency orientation in every-day life and assessed sufficiency orientation, basic psychological need satisfaction, self-reflection, subjective well-being, and time affluence before (T1), directly after (T2), and four weeks after the intervention (T3). Contrary to our predictions, there was no significant difference between the experimental and the control group. Sufficiency orientation increased across groups. Basic psychological need satisfaction was the strongest predictor of sufficiency orientation. There were positive relations with subjective well-being. Targeting basic psychological need satisfaction as a potential underlying driver of sufficiency orientation seems to be a promising avenue for designing interventions. Employing a need-based, humanistic approach to design psychological interventions is in line with the aims of sufficiency to meet every human’s basic needs, in a socio-ecologically just world.