*2.4. External Contexts*

External contexts refer to individuals' objective factors when adopting a particular behavior [59]. Specifically, external contexts include advertising, government regulations, legal and institutional factors, material incentives and costs, technological constraints and the availability of infrastructure to support the behavior [60,61]. The external contexts, as the external environment faced by individual psychological factors, can create opportunities and generate constraints for forming personal attitudes and behaviors [19]. Many scholars found in their practical studies that external contexts play a significant role in promoting or hindering the implementation of SCB [19,62]. According to the promotion and inhibition of external contexts on individual behavior, this study divided the external contexts into positive contexts and negative contexts [21].
