Date: 2026-08-28 Venue: Annual Conference of Experimental Sociology (ACES 2026) Location: Paris, France
While climate concern is widespread globally, the translation of pro-environmental attitudes into concrete behavioural change remains one of the central puzzles of environmental sociology. This attitude-behaviour gap is well-documented: despite high levels of climate awareness, individual lifestyle changes lag behind what decarbonization pathways require. Existing explanations have focused on individual-level barriers such as cost, convenience, or psychological distance from climate consequences. Yet a growing body of research suggests that behaviour is also shaped by what they perceive others around them to be doing. This study aims to measure network effects in the diffusion of two daily pro-environmental behaviours (PEB): meat consumption and daily use of soft mobility. Indeed, in the context of accelerating temperature increases, public policies aim to promote adaptation through gradual changes in lifestyles. However, while most countries have high levels of climate concern, the translation of these pro-environmental attitudes into behaviours remain largely unexplained. I introduce SEQAMI, a mobile app designed to collect longitudinal behavioural and attitudinal data on PEB over several weeks through a daily logging system. Participants (targeted sample size is N = 800) were randomly assigned to one of four experimental conditions structured along a 2×2 design, crossing network topology (clustered ring lattice vs. random rewired network) with the presence or absence of neighbours' sociodemographic information (gender, age, education level), or to a control group receiving no social information.
Participants in experimental conditions were shown, on a daily basis, how many of their six neighbours had performed each PEB the previous day. This experimental design addresses two theoretically motivated hypotheses: (1) does peer influence increase the probability of PEB adoption in the short and medium term; (2) does network structure moderate diffusion outcomes. By comparing total diffusion between clustered and random networks, the study empirically tests if PEB diffusion follows a complex contagion process. I further test whether demographic homophily between participants and their neighbours moderates these effects, and whether individual-level conditional cooperation scores predict susceptibility to peer influence. [At the time of the communication proposal] Data collection is currently underway. Using multilevel logistic regressions with individual fixed effects and individual-level baselines as within-person counterfactuals, preliminary results show an increase in PEB adoption among participants exposed to descriptive norm information about their peers. This effect is higher in clustered networks than in random networks, suggesting that PEB diffusion may be better conceptualized as a phenomenon of complex contagion. Final results from the completed data collection will be presented at the conference. Pre-registration of the experiment is available here: https://osf.io/wzj9m/overview.