Rigorózní práce Behavior and Institutional Change Jaromír Baxa The main aim is to explain, why we can observe strong persistence in human or firm behavior despite substantial change of economic environment and why persistence of informal institutions occurs. During recent two decades there were various trials to provide explanation of persistence of behavior based on presumption of existence of path dependency and increasing returns, reflecting findings of experimental economics with methodological background in bounded rationality or using simulations of interactions or networks. My practice is slightly different as I'm trying to incorporate findings of cognitive psychology and social cognitive learning into economics. Traditional microeconomics relies heavily on simplistic psychological behaviourism, field based on proposition that behaviour can be researched scientifically without recourse to inner mental processes. According to cognitive psychology other notions are relevant for understanding behaviour as memory, attention, perception, knowledge representation, etc. This means that simply not only incentives but also learning, experience, social network, imitation and other phenomenons does matter and that adjustment processes differ through population of agents and they are not straightforward, neither instantaneous nor costless. Cognitive psychology tells us that such routines are based on subjective mental models at the individual level. Evolution of behavior can be now understood as evolution of those routines and mental models, and thanks to their nature routines have high propensity to long persistence despite changing environment. Other reason for persistence of routines is nature of learning process itself. In accordance with psychology I deal with two types of learning, not only with learning-by-doing, which is very often used in economics, but also with so called observational learning – learning according to expectations of future development and learning through imitation. The later prevails in case of risk-averse population and is more common in situations where costs of possible mistakes are to high. So learning depends not only on economic environment but also on social environment, on experience and knowledge how to find what is important and what is not and so learning processes are highly path dependent and everything else than instantaneous. Such knowledge and experience necessarily differ through population as well as available set of information and this leads to divergence in behavioural regularities. If consequent process of adaptation through imitation and learning leads to convergence is not clear and we suppose that no universal law exists. Evolution of behavior can be now understood as evolution of routines and mental models, and thanks to their nature routines have high propensity to long persistence despite changing environment. This approach is applicable to evolution of informal institutions and it allows to explain persistence of them using shared mental models. Then informal institutions are seemed as behavioral regularities used by decisive part of the society and their evolution can be now described as diffusion of new behavioral regularity in the society and modeled using biased transmission approach. Finally formal models of contagion and of cultural transmission are presented and evaluated. As far as path dependent character of institutional change concerns, it seems that from the perspective of cognitive psychology it is only acknowledgement for existence of long adjustment processes. And that no universal factors which can either ease or limit such adjustment can be found and so economists should respect historical and branch specificity. Abstrakt: Hlavním cílem této práce je vysvětlit přetrvávání vzorců chování jednotlivců i firem navzdory významné změně v jejich prostředí a také, proč se objevuje značná setrvačnost v neformálních institucích. V minulých letech zde bylo několik pokusů, počínaje vysvětlením založeným na existenci path dependency, pomocí experimentální ekonomie nebo simulací. Můj přístup je odlišný, snažím se konzistentně pracovat s poznatky kognitivní psychologie a sociálního učení. S pomocí rutinního chování a mentálních modelů jako obrazů reality v hlavách jednotlivců jsem pak vysvětlil existenci institucí jako důsledek sdílených mentálních modelů. Neformální instituce jsou pak považovány za jistý druh ustálených vzorců chování a jejich evoluce pak může být popsána jako difuze nového vzorce chování ve společnosti a modelována pomocí modelů difuze nebo kulturní transmise. English abstract The main aim is to explain, why we can observe strong persistence in human or firm behavior despite substantial change of economic environment and why persistence of informal institutions occurs. During recent two decades there were various trials to provide explanation of persistence of behavior based on presumption of existence of path dependency and increasing returns, reflecting findings of experimental economics with methodological background in bounded rationality or using simulations of interactions or networks. My practice is slightly different as I'm trying to incorporate findings of cognitive psychology and social cognitive learning into economics. Cognitive psychology implies that behavioral regularities, routines, are based on subjective mental models. Evolution of behavior can be now understood as evolution of routines and mental models, and thanks to their nature routines have high propensity to long persistence despite changing environment. This approach is applicable to evolution of informal institutions and it allows to explain persistence of them using shared mental models. Then informal institutions are seemed as behavioral regularities used by decisive part of the society and their evolution can be now described as diffusion of new behavioral regularity in the society and modeled using biased transmission approach. Finally formal models of contagion and of cultural transmission are presented and evaluated.