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개인 투자 행동은 금융 서비스가 서비스 경제에서 점차 중요해지면서 최근 경제학, 심리학 및 마케팅 분야의 연구자들로부터 많은 주목을 끌고 있다. 금융 상품은 투자자의 재무 상태에 중대한 영향을 미치는 중요한 의사결정 영역임에도 투자자들은 심리적, 인지적 편향에서 자유롭지 못해 중요한 의사결정에서 최적의 결과에 이르지 못한다. 과잉확신의 편향은 자아에 대한 과도한 예측이나 확신으로 인해, 랜덤한 사건의 트렌드를 자신의 신념을 강화하는 쪽으로 해석하여 손실이 일정기간 반복되면 이제 이익이 날 것으로 예측하는 갬블러의 오류를 더 범하게 한다. 본 연구는 손실 영역을 대상으로 자아 판단의 편향이 불확실성하의 의사결정에서 제한된 과거 정보에 기반 한 미래사건 예측 시 어떠한 오류를 범하게 되는 지, 그 결과 의사결정의 성과에 어떤 영향을 미치는 지를 분석하였다. 본 연구 결과, 과잉확신의 소비자는 반복 손실에서 주가 상승에 대한 예상으로 손실 주식을 손절매하지 못하고 오히려 더 매수함으로써 투자 성과를 악화시키고 있었다. 과잉확신 소비자는 주식 투자를 관리 가능하다고 지각하고 비이성적으로 행동할 위험이 있다는 점에서 갬블러와 닮아 있으며, 투자에 대한 접근 방식에 있어 갬블러의 오류를 범할 가능성이 높다고 할 수 있다. 본 연구는 투자 행동을 대상으로 중요한 두 가지 바이어스의 관계를 밝혔으며, 이들 바이어스가 의사결정 과정 및 성과에 미치는 영향을 제시하였다는 점에 그 공헌이 있다.
Individual investment behavior attracts a great deal of attention from researchers in the fields of economics, psychology, and marketing, as the financial industry has become increasingly important in a service economy. Financial investment is one of the most important decision-making areas, since it can have crucial consequences for investor welfare. However, consumers are not free from psychological biases in their decision-making processes, and these powerful biases often hinder sound performance. People use heuristics to solve complicated and difficult problems under uncertainty. However, due to limited intelligence or lack of information, heuristics often lead to serious and systematic errors. When a random sequence shows a pattern, consumers assign meaning to it. They integrate it into their preexisting theories, thus biasing the evaluation of new information in the direction of their initial belief, resulting in an incorrect probability judgment. The Gambler’s Fallacy is that most people erroneously believe that black is now due after observing a long run of red on the roulette wheel, presumably because the occurrence of black will result in a more representative sequence than the occurrence of an additional red. In the investment area, consumers may also commit the Gambler’s Fallacy by expecting a stock price to increase after experiencing a repeated decrease in stock prices. The Gambler’s Fallacy explains the disposition effect (i.e., the tendency to hold on to losing stocks and to short-sell winning stocks), which is identified as one of the principal causes of poor investment performance. According to this theory, consumers experience the disposition effect by holding (selling) stocks when they believe that a price increase (decrease) is now due after observing a long run of losses (gains). Meanwhile, prior studies in the field of behavioral finance have shown that overconfidence is a common trait among many investors. Social scientists agree that there is a motivation in us to master our environment and to “beat the odds” (Langer, 1975), even though the phrase is an oxymoron. Nevertheless, people will continue to attempt to control chance events. Further, it has been shown paradoxically that more difficult problems elicit greater feelings of confidence in being able to solve them (Langer, 1975). The greatest satisfaction would therefore result from being able to control the seemingly uncontrollable. Researchers find that the tasks likely to give rise to overconfidence are those that are purely random, personally important (Frank, 1935), difficult (Odean, 1998b), and require a high level of involvement (Langer, 1975). In many ways, stock investment corresponds to these characteristics, as it is unpredictable, uncontrollable, complex, and difficult. Thus, individuals may more easily fall into overconfidence bias in stock investment compared to other areas. Due to an inflated estimation of their valuation, overconfident consumers are inclined to more easily commit errors and show erroneous stronger beliefs in a probability judgment based on limited past information compared to less overconfident consumers. While favorable signals (recent price increases) are interpreted as confirmation of their prior beliefs and actions, unfavorable signals (recent price declines) are discounted. As a result, they show a stronger belief in mean reversion. In this paper, we show the relationship between overconfidence and misconceptions of chance in the loss condition. We examine how bias in self judgments leads to bias in probability judgments in investment decision making and consequential influence on performance. In survey experiment, we examined the influence of overconfidence on the estimation of future occurrence and degree of confidence in their estimation during the roulette and coin toss games. In another experiment, we developed a computer-based mock stock investment game in which we manipulated repeated losses, measured overconfidence of real world investors, and examined how gambler’s expectation of overconfident consumers is reflected in buying and selling behaviors. The result of the survey experiment indicated that more overconfident individuals anticipated greater mean reversion than less overconfident individuals and showed a stronger confidence level in their anticipation. The result of the mock stock game revealed that more overconfident investors bought more losing stocks than less overconfident investors, exposing themselves to greater risk due to greater expectations of price increases, which leads to a poor investment performance. Overconfident consumers seem to resemble gamblers in that they have the illusion of control on stocks, behave irrationally, and are likely to fall prey to the Gambler’s Fallacy in their approach to investing. This study makes the following theoretical contribution: it examines the relationship of two important biases in decision making and analyzes their influence on the decision-making process and consequent effect on performance. Previous studies demonstrated that overconfidence leads to poor performance through increased trading and earlier selling in a gain. Our study complemented previous literature by showing that overconfidence leads to more buying and holding in a repeated loss condition, thereby resulting in a poor performance.
키워드열기/닫기 버튼
Decision-making, Overconfidence, Gambler’s Fallacy, Heuristics, Performance, Investment Behavior
