Identifying Emotional Bias in Investment

John is a portfolio manager who recently experienced a significant drop in the market that affected his investments. Due to this downturn, he becomes overly cautious and begins to avoid investing in equities, even though his long-term strategy is to maintain a diversified portfolio with a substantial equity component. He is now primarily focused on fixed-income securities, fearing further losses.

This situation illustrates how emotional biases can impact investment decisions. What emotional bias is John most likely exhibiting in this scenario?