Using an Eye Tracker to Examine Behavioral Biases in Investment Tasks: An Experimental Study.

Contrary to the premise of rational models, which suggests that investors' aggregate portfolios are the appropriate informational asset for evaluating a file performance, we find, using an eye tracker, that investors spend more time looking at performances of an individual asset than at the performances of the overall aggregated portfolio and at the net value change more than the assets' final value. We also find that investors look at the monetary value change longer than at change in percentages. Specifically, participants look longer at the value change of gaining assets than at the value change of losing assets. We propose the possibility that investors are not only engaged in judgment when evaluating their portfolio (leading to loss aversion and mental accounting) but may also be predisposed to looking for reassuring elements within it. Thus, it may be that humans use mental accounting by nature and not necessarily by judgment.