I. JUDGMENT and DECISION BIASES In the first section of the survey, psychological effects which are relevant for securities markets are defined. These effects mostly derive from common roots. Since it is almost impossible to analyze all the given data, rules of thumbs are preferred such as algorithmic, heuristics and mental modules. Heuristics must be applied to appropriate problems and cases so that they can be effective. There have been debates between both economists and psychologists on how heuristics do. Most of the economists believe in the fact that errors are independent across individual investors. The idea ends up with the equilibrium point and correction. However people mostly share similar heuristics gained from experience. Human mind is not designed solely to make good decisions but also to experience pleasantness. Individuals believe that they are better than they actually are. Also decisions are affected by feelings and mood of decision maker individuals. People can learn from past experiences and failures. However learning is hard and self-deception makes people realize their success more than failures and losses. Many (though not all) of the cognitive biases are stronger for individuals with low cognitive ability or skills than for those with high ability or skills, consistent with biases being genuine errors. A. Heuristic Simplification
A.1 Attention/Memory/Ease-of-processing effects Lack of full attention, limitations on memory and processing capacities of individuals forces them to create a selective focus. Psychology of investors is affected from those limitations during decision process. If information is able to attract the individual because of any personal or social reasons –past events, background, emotional life etc. - the information becomes more obvious than the rest. People are not usually able to