The ultimate goal of social sciences theories is the empirical proof of structural and analytic theories. Investors usually make investment decisions using fundamental, technical and judgmental analysis (market sentiment). Since the investors are regret aversion, in order to evaluate and prove the various models of decision making by them, we can use the amount and intensity of regret of investors after making decisions based on the above mentioned patterns. So, in the present study, we first studied the effect of the regret aversion on applying different patterns of decision making by individual investors in order to determine the dominant pattern in the capital market of Iran and then the empirical proof of this pattern based on the amount and severity of regret after adoption of decision in 2017. Data were collected using questionnaires in two stages. The findings of the research showed that there is merely a positive and significant correlation between regret aversion bias and the decision making model of individual investors based on judgmental analysis (market sentiment). Therefore, it can be concluded that decision-making based on market sentiment is the dominant model of decision making by individual investors in Iran's capital market. However, the dominant decision-making pattern chosen by individual regret aversion investors has more amount and intensity of regret after adoption of decision. Therefore, regret aversion concept isn’t confirmed empirically (that is, having a lower sense of regret after decision-making based on the dominant model).