Towards a biased mindset: An extended Theory of Planned Behaviour framework to predict farmers' intention to adopt a sustainable mange control approach.

Resistance against macrocyclic lactones is emerging in Psoroptes ovis mites, the cause of psoroptic mange in sheep and cattle. Therefore, sustainable mange control approaches should be implemented to prevent or slow down resistance. To ensure a proper implementation of such approaches, it is crucial to understand the factors that may impede or facilitate adoption of these practices among farmers. A conceptual model that combines insights from the Theory of Planned Behaviour (TPB, Ajzen, 1991) - a theory that predicts human behaviour -, with insights from behavioural economics (Camerer, 2004; Samson, 2016) - a theory that assumes that behavioural biases or reasoning errors are pervasive in decision-making -, was developed to predict farmers' adoption intention. In particular, this paper examines how behavioural economics can influence farmers' beliefs related to sustainable mange control and through which pathways these biased beliefs can predict adoption intention. A cross-sectional survey study amongst 174 Belgian Blue cattle farmers has been conducted and Structural Equation Modelling was used for analyses. In particular, the model shows that farmers' positive attitudes towards a sustainable mange control method (attitude) and their perceptions of how others evaluate the sustainable control methods (subjective norms) more strongly predict adoption intention than perceived behavioural control. Additionally, the model shows that adoption intention is explained by the bandwagon bias -the belief that other farmers have a positive opinion about the control method-, and availability bias - farmers who have the belief that mange occurs often on their farm - through the determinants of TPB. Although this bandwagon bias influences farmers adoption intention, the rather low presence of availability bias might explain why adoption intention of a sustainable mange control method is limited. Next, retaining to the default treatment (default bias) influences farmers' belief that they are capable of implementing control methods on their farm (perceived behavioural control), while the belief that implementing a control method is perceived as a cost for their farm rather than being beneficial (loss aversion bias) negatively influences attitude and perceived behavioural control. We further discuss important implications that can incite farmers' adoption intention.