Using a simulation experiment, the authors show that investors react to short-term feedback. Both near-term and cumulative poor performance drive investors to spend more time evaluating their portfolios. The authors find that investors are more likely to tolerate underperforming investments during periods of good overall portfolio performance.

An investor’s behavior depends on his or her investment style (growth, value, judgmental, or technical). The authors find significant differences within investment styles regarding the amount of search effort during uptrending versus downtrending markets. Across each style classification except value, search and exploration activity varies according to market conditions (e.g., an uptrending or downtrending market). Value investors generate significantly fewer transactions. Technical investors exhibit the most reactionary behavior. The authors find that investors diversify their research efforts largely during times of uncertainty or negative returns regardless of whether the investors’ approach is technical or fundamental.

The majority of sales in the study’s data involve stocks with larger-than-average losses or underperformance, which is contrary to the “disposition effect.” The authors also observe this effect among value investors, suggesting that this style is not immune to price patterns, particularly in times of market stress. By shedding further light on behavioral biases in various market environments, the authors’ results are useful for investment professionals.

The authors conduct an experiment with 57 subjects participating in a computer simulation. All participants have some experience with and an above-average interest in financial markets.

The authors use a 12-month period (May 2010–April 2011) to conduct the three-hour simulation, with 98 large-cap S&P 500 Index stocks composing the investment universe. Participants are informed that all stocks in their universe are large cap and liquid, but the company names are anonymous. Sector classifications are made known to the participants, who can (but are not required to) evaluate and make changes to their portfolio holdings in five-day intervals.

Participants are asked to define their investment style as either growth, value, technical, or judgmental. Both technical and fundamental indicators are made available to the participants to drive portfolio decision making. No short selling or leverage is allowed. Participants are unaware of the performance of other participants.

The authors hypothesize that feedback on performance will trigger reactionary behavior among the participants when the feedback involves unusually large market moves. Assuming that the recent volatile environment will reinforce these effects, the authors expect to observe significant differences with respect to gains and losses.

The authors capture the participants’ behavior via mouse clicks and keyboard strokes. The results of the study strongly support the authors’ hypothesis of reactionary behavior in response to feedback, particularly when losses occur. This finding is consistent across all styles, although the intensity of the behavior varies across investment styles.

The authors shed additional light on investor behavioral biases. Understanding these biases is crucial for traders and analysts seeking to gauge current market sentiment as well as for advisers seeking to explain existing market dynamics to their clients. The investor behaviors the authors identify are consistent with traits identified in prior market behavior studies (e.g., anchoring under uncertainty, prospect theory, loss aversion, and status quo bias). The authors’ evidence is compelling; however, several factors are worth keeping in mind when evaluating the results.

The data contain two distinct phases: a correction followed by either a choppy rally phase or a relatively steady rally phase. The nature of the trading environment could have an impact on style-related behavior. The lack of “avoidance” from value investors may be because of the stronger overall performance of value that occurred in the experiment’s timespan rather than any inherent bias with that style.

Participants may have changed their style throughout the experiment in a reactionary manner. If so, it would be difficult to make conclusions regarding reaction by style. The strong performance of the S&P 500 over the course of the study (13.9%) could also have affected the results. A future study in which both market conditions and overall index performance are reversed would be insightful.

Finally, participants had no prior knowledge of the market environment that preceded the beginning of the study. Thus, participants’ views were framed only by the real-time data generated over the course of the experiment, which is unrealistic.