Course 407: Psychology and Investing
Confirmation Bias
In this course
1 Introduction
2 Overconfidence
3 Selective Memory
4 Self-Handicapping
5 Loss Aversion
6 Sunk Costs
7 Anchoring
8 Confirmation Bias
9 Mental Accounting
10 Framing Effect
11 Herding
12 The Bottom Line

Another risk that stems from both overconfidence and anchoring involves how we look at information. Too often we extrapolate our own beliefs without realizing it and engage in confirmation bias, or treating information that supports what we already believe, or want to believe, more favorably.

For instance, if we've had luck owning Honda(HMC) cars, we will likely be more inclined to believe information that supports our own good experience owning them, rather than information to the contrary. If we've purchased a mutual fund concentrated in health-care stocks, we may overemphasize positive information about the sector and discount whatever negative news we hear about how these stocks are expected to perform.

Hindsight bias also plays off of overconfidence and anchoring behavior. This is the tendency to re-evaluate our past behavior surrounding an event or decision knowing the actual outcome. Our judgment of a previous decision becomes biased to accommodate the new information. For example, knowing the outcome of a stock's performance, we may adjust our reasoning for purchasing it in the first place. This type of "knowledge updating" can keep us from viewing past decisions as objectively as we should.

Next: Mental Accounting >>


Search
Print Lesson |Feedback
Del.icio.us Del.icio.us | Digg! digg it
Learn how to invest like a pro with Morningstar’s Investment Workbooks (John Wiley & Sons, 2004, 2005), available at online bookstores.
Copyright 2010 Morningstar, Inc. All rights reserved. Please read our Privacy Policy.
If you have questions or comments please contact Morningstar.