Subject of this thesis is behavioural economics, new interdiscipliary field of science, which combines elements from fields of psychology and economics. Neoclassical economy assumptions that people are rational and that they make rational decisions when asked to. But throughout the history some anomalies in behaviour were noticed and it has come to conclusion that people are, as a matter of fact, irrational. Daniel Kahneman and Amos Tversky, authors of prospect theory, were two scientists that had a huge impact on development of this new discipline. Their work had a big influence on Richard Thaler, founder of behavioural finances, which are subdiscipline of behavioural economics, and on Herbert Simon who is considered as one of the pioneers in behavioural economics. In this thesis we have explained the application of behavioural economics, with an emphasis on social norms. Also we have conducted an experiment in Department of Economics on University of Zadar, whose settings and results are available in this thesis. Also we have discussed about future of behavioural economics where we talked about neuroeconomics and neuromarketing and also ethical questions which have emerged from these relatively new field in behavioural econom