Stock Market Psychology: Behavioral finance, new research, and beyond

Wednesday, June 11, 2008

Why It's So Hard to Let Go (Hint: It's all in your head)


Another brilliant new study from the SPAN lab at Stanford elegantly describes the neural predictors of the endowment effect. If you recall from some of our past blog posts, the Endowment effect describes the tendency for people to overvalue what they own, and value less what they don't.

A classic example of the Endowment Effect is playing out in the housing market. In a normal housing market, people value their own houses more than is justified by what the market will pay (often about 12% over the market price). During a market downturn, the normal homeowner tries to sell their house for an average of 33% over market value (per Hersh Shefrin on NPR, March 30, 2008).

So what could drive people to cling to what they own and demand a higher price for it? It turns out that we are hardwired for "scarcity," and we don't want to let go of something we already have.

It even appears that we fear losing something we think we are going to get, and we'll chase it with a higher price at an auction (such as Ebay). This is seen in an insightful study by James Heyman, Yesim Orhun, & Dan Ariely called : AUCTION FEVER: THE EFFECT OF OPPONENTS AND QUASI-ENDOWMENT ON PRODUCT VALUATIONS).

Brian Knutson, Elliott Wimmer, Scott Rick, Nick G. Hollon, Drazen Prelec, and George Loewenstein demonstrated in a study published by Neuron tomorrow, called Neural Antecedents of the Endowment Effect, that activation in the anterior insula (appearing in the top image), predicts the strength of the Endowment Effect.

Importantly, there are "individual differences" in the intensity of the Endowment Effect. That is, the activation in any one person's right anterior insula predicted how much value they assigned (and how much money they would demand from a bidder) for a consumer product. Each individual is different in this regard. And I imagine (though I have not seen it shown experimentally) our own propensity to the endowment effect changes over time depending on recent events in our lives.

Remember, the anterior insula often activates when someone is afraid of losing something, when they are in physical (and imagined) pain, and when they are experiencing disgust. So the idea of giving up a product is actually painful, and so we assign a higher value to it - to avoid the pain of loss.

Maybe that's another reason why it's so hard to let go of a sagging stock, especially one with a great story that is a former high-flyer. It's actually painful! More on this study and its implications later...

Happy Investing!

Richard

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Tuesday, October 02, 2007

Neuroeconomics 2007 -- Happenings at the SFN Annual Conference


As if Boston wasn't brainy enough with 51 colleges and universities (see this list), the annual neuroeconomics conference was held there this past weekend. Excellent new neuroscience research gave the audience's grey matter some delightful brain candy to chew on all weekend. I'll just list a few of the fascinating findings below. There are many more that I will not mention for space reasons.

In an effort to break the conference's three days of presented research down into a bullet-point-speckled summary, I'll organize the studies in the three following categories:
1) How people, on average, make personal financial decisions. Such experiments manipulated conditions of risk, reward, punishment, and ambiguity or uncertainty in order to see what types of brain activity correlate with (or even better, predict), not-mathematically-rational financial decisions.
2) How people make social financial decisions. These are often simulated using strategic games played with others (or computers dressed as others) and are relevant to morality in general. Such decisions affect other people (and usually oneself) financially.
3) How people are different from one another in their financial decisions, especially in regards to the brain activity that leads to their different choices under similar conditions.

Under personal financial decisions, Peter Bossaerts excellent (and intricate) study of traders in a simulated market was one of the most fascinating. He found that excellent trading (in this case, based on "tape reading") did not appear correlated with mathematical ability. Rather, it required a unique ability to understand the minds and intentions of others (variously called "theory of mind" or empathy). His study is far too complicated to explain in more detail here.

Researchers at NYU demonstrated the behavioral (and some neural) consequences of loss aversion in an investment-type task. Interestingly, the NYU researchers asked subjects to view all their upcoming "investments" in terms of a portfolio to see if it reduced their loss aversion (it did, but not entirely). They also found that an individual's level of loss aversion correlated with a greater SCR response (arousal) to losses versus gains.

Researchers from the Soochow and National Yang-Ming Universities of Taiwan, in the Soochow Gambling Task, have continued to demonstrate that people prefer small high frequency gains punctuated by occasional large losses (negative overall expected value) to small losses that are occasionally punctuated by a large gain (positive ooverall expected value), even after they are told the odds and probabilities. See my book for more detail about this remarkable result.

Brian Knutson's group at Stanford found that priming subjects with a sexy photograph increased NAcc activation (in the reward system) and increased their willingess to take risky financial gambles, even though finance has nothing to do with seeing a sexy photo (I presume).

In a study at NYU using one of Paul Glimcher's tasks, adolescents were found to be more "ambiguity seeking" than adults, but more "risk-averse" than adults when they knew the odds of the gamble. Per the researchers, perhaps their drive to learn and explore overcomes an aversion to known risks that they might not be skilled enough to handle yet.

In the second category of studies, Paul Zak's group at Claremont Graduate University found that touch (a massage of Player 2) more than tripled the amount that Player 2s (in the Trust Game) gave back to Player 1s. And the amount of $$ returned was correlated with blood oxytocin levels (especially baseline level). Recall that in the Trust Game, Player 2 isn't obligated to give anything back to Player 1, so this is a pretty profound finding. The Trust Game is described in my book in some detail.

In the third caegory, studies on how people make decisions differently, it is clear that there are observable patterns of brain activation, circuitry, underlying personality styles, and patterns of behavior such as:
1) Intuitive versus reasoning problem-solving,
2) Those who succumb to regret aversion (avoiding organizing their finances, for example) versus those who plan for the future,
3) Impusive versus more deliberate decision makers,
4) Maximizing versus satisficing decision makers, and
5) Machiavellian (primarily self-interested) versus more cooperative decision makers.
The first four results (preliminary) were found by Scott Huettel at Duke University's Center for Neuroecnomic Studies.

Other researchers found that the ability to self-reduce one's level of fear (and one's physiological fear-resonse) was correlated with the thickness of a part of the brain (VMPFC) that inhibits the amygdala and appears to generate soothing thoughts. Also, thickness of the insular cortex correlated with an increased sensitivity to aversive (bad) outcomes.

One interesting mention was of prior studies indicating that one's score on a "Private Body Consciousness Scale" (one's degree of somatic preoccupation) correlates with an increased susceptibility to the placebo effect. Now if one supposes that marketing is in some way activating placebo-effect-type brain circuits (people feeling good about themselves for a product purchase or consuming a branded product, for example), then it might be true that brain activity predicting the placebo effect will also predict whether one believes that higher prices denote higher quality (and better taste). According to Hilke Plassmann at Caltech, they do. That is, people who scored highly on body consciousness, when they drank a wine they was priced higher (but identical) to a lower-priced wine, thought it tasted better (and this finding was correlated with specific neural activation).

Other researchers found that individuals' "risk-aversion" to financial gambles appears to have a broad brain ciruit which governs it and indicates a specific personality type.

I hope this laundry list of findings is interesting and useful for all who could not attend!

Cheers,
Richard

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