New large hydroelectricity (hydro) power plants have been characterised as an essential component for Chile's economic development. Rivers are the only locally available natural resource from which a sufficient energy output for the growing national demand can be provided with currently existing technology; additionally, hydro is argued to be comparatively low in terms of economic and environmental costs. In recent years, the development of new hydro dams has faced increasing opposition from diverse ethnic, environmental, and political groups. Local opposition could be explained in terms of the environmental and societal costs that it bears upon the residents who live near to projects. Additionally, the construction of dams has been previously linked to irregularities prompted by the national government and companies. In a complex socio-political scenario, opposition to hydro has grown to become a national-scale phenomenon. The aim of this thesis was to provide insights to better understand how people form their views regarding hydro and technologies alike. Previous advances in socio-psychological research and theory, pointed towards three variables to be considered as potential explanations to account for the levels of acceptance of new power plants: perceived consequences, trust in stakeholders, and identification with contextually relevant groups. These issues were examined in four studies: (1) through a thematic analysis of articles in Chilean newspapers; (2) through a correlational assessment of the variables of interest, using a survey focused on the public views on electricity generation; (3) through an experimental study focused on the relationship between identification with groups and trust; and (4) through integrative theoretical models, using competing structural models. Results from these studies support the central proposition that people form their views on hydro based on the levels of trust that they hold towards stakeholders, and that levels of trust are influenced by people's identification with dominant and subordinate national groups. Moreover, it is proposed that people adopt prototypical anti or pro-hydro norms from the groups they feel more identified with.