Doctoral dissertation deals with the stabilization function of fiscal policy in a rather new way, by including the behavioural component in the economic model. Instead of investigating the widely researched direct effect of fiscal policy on macroeconomic activity through a fiscal multiplier, it is examined whether fiscal authorities could act indirectly and increase the effectiveness of implemented measures by influencing consumer optimism. Panel data analysis examines the effects of changes in different categories of government spending and taxation on consumer confidence in the EU member states. It is also scrutinised whether consumers react to fiscal changes differently depending on the phase of the business cycle, or in other words, whether there is an asymmetry in the perception of the economic environment in the presence of extraordinary circumstances such as crises. The results show that consumers negatively perceive the increase of government spending and taxation for almost all observed categories, while in the downward stages of the business cycle, when there is greater economic uncertainty, consumers become more pessimistic due to the same fiscal changes. Economic policymakers should take this into account when designing policy measures. It is recommended that in order to stabilize the business cycle, in a situation of low public indebtedness, fiscal expansion is carried out by reducing the tax burden on labour and capital. In the presence of high public indebtedness (debt crisis), fiscal austerity is advised by reducing government spending in sectors suffering from severe inefficiencies.