The study looked at how internal factors like financial knowledge, fear of losing money, and overconfidence affect how investors make decisions. They surveyed investors in Central Java, Indonesia, and found that being financially literate helps investors make better choices. However, being afraid of losing money can lead to poorer decisions. Surprisingly, being overconfident doesn't seem to have a big impact on decision-making. This suggests that understanding investors' behaviors can help predict stock market movements and improve overall market performance.