Psychological factors play a crucial role in shaping investors' decisions. Emotions like fear and greed often drive choices. When fear dominates, investors might panic and sell off their investments, leading to losses. On the other hand, greed can blind individuals, causing them to take excessive risks. Cognitive biases also impact decision-making. Confirmation bias makes investors seek information that confirms their preconceived notions, while anchoring bias leads them to rely heavily on initial information. Herd mentality is another powerful force, as people tend to follow the crowd without questioning their choices. Understanding and managing these psychological factors is essential for successful investing.