Behavioral economics is a fairly new field within science economics, which attempts to explain human behavior from the point of view of social preferences and heuristics. He bases his study on the processes of taking of decision by an individual, but unlike the model of homo oeconomicus (an expression formulated by John Stuart Mill in the mid-19th century as a useful idealization for the economic discipline) starts from a conception of rationality limited individual (fallible and biased decisions). Advances in this discipline. They are essentially nourished by field work and experiments in laboratories, as well as well as the advances of other sister disciplines such as psychology, neuroscience, cognitive science, etc. Behavioral and experimental economics were Nobel laureates in economics in 2002 awarded ex aequo to Daniel Kahneman and to Vernon Smith. Smith's experiments have focused on the recreation of artificial markets with the participation of students demonstrating that prices in these fictitious markets converge towards equilibrium. These experiments focus currently on phenomena of collective irrationality, such as the formation of bubbles. Kahneman has focused his studies on these phenomena, developing, together with Amos Tversky the prospect theory, where the decision framework exerts an impact on the assessment of potential gains and losses.

In the analysis of financial time series, the Autoregressive models with Conditional Heteroskedasticity (ARCH) and their generalization, the GARCH models, have been widely used, demonstrating their good qualities for modeling the volatilities typical of this type of series. As an alternative, Switching Markov models have emerged that allow the inclusion of random phenomena as possible structural changes in the mean or variance process. This paper aims to demonstrate the best suitability of these regime-switching processes for modeling the conditional variance of the IBEX-35 Index returns.