Mark is a seasoned investor who has successfully managed his own portfolio for over two decades. However, recently he has shown a troubling tendency to react emotionally to market fluctuations. For example, after a significant market downturn, he sold off many of his equity positions at a loss, citing a feeling of panic and a fear that the market would continue to decline.
Behavioral finance posits that such emotional responses can lead to suboptimal investment decisions. In Mark's case, his emotional reaction is largely driven by a specific emotional bias that affects his risk perception and decision-making process.
Which of the following emotional biases most accurately describes Mark's behavior?