Showing posts with label experiment. Show all posts
Showing posts with label experiment. Show all posts

Monday, January 12, 2009

Why you can't always make good decisions

We all make bad decisions sometimes. In some contexts, to a certain extent, psychologists know why.
Much research on the subject was done by Daniel Kahneman and Amos Tversky, who shared the 2002 Nobel Prize in Economics for their models of how intuitive reasoning is flawed in predictable ways. Kahneman is now professor emeritus at Princeton University, and Tversky died in 1996.

But other researchers are working on showing that, when it comes to more basic judgments, we're not so bad.

Research in the current issue of the journal Neuron offers a mathematical model for how people make decisions about visual stimuli on a computer screen. They found that humans make accurate judgments about cues they can see.

"We're discovering that humans aren't so stupid after all," said Alexandre Pouget, co-author of the study and associate professor of brain and cognitive sciences at the University of Rochester in New York.

Participants were asked to look at moving dots on a screen. Many of the dots moved randomly, but some moved in one clear direction. Researchers found that people very quickly realized which way the non-random dots were going.

The work complements that of Kahneman and Tversky in that it shows humans are good at lower-level, nonlinguistic tasks, while perhaps not so good at higher-level probability problems involving words, he said.

"In simple perceptual decisions -- you have a visual stimulus on the screen and you have to make decisions about it -- it looks like you do accumulate the evidence optimally, given that uncertainty," Pouget said.

Psychologists believe the human mind has two systems for decision-making: intuitive and reasoning. The intuitive system is emotional, fast, automatic but slow-learning, while the reasoning system is emotionally-neutral, slow, controlled, and rule-governed. Neither, of course, is always right, but there are certain simple problems that reveal flaws in intuition.

A classic example that Kahneman has often used in lectures is this math problem: A bat and a ball together cost $1.10. The bat costs a dollar more than the ball. How much does the ball cost?

Your intuitive system may quickly tell you that the ball costs 10 cents. That would be an easy solution, but it would also be incorrect.

In fact, if the ball costs 10 cents, that would mean the bat costs $1.10, so the two together would be $1.20 -- violating the first piece of information you had. A little algebra, or a little more thought, reveals that the ball must have cost 5 cents. Oops!!.

Now, think about tossing a coin six times. Which is more likely: heads-heads-heads-tails-tails-tails or tails-tails-heads-heads-tails-heads?

You might think that the second one seems more random, so it's more likely. That error would fall into what Kahneman and Tversky would call the representativeness heuristic or, more specifically, the misconception of chance -- in other words, we tend to go on our intuitive notions of what an unrigged coin toss should look like rather than actually calculating.

If you think about the probabilities of each, you'll realize the two combinations are equally likely.

A related concept is called fundamental attribution error, demonstrated by Edward Jones and Victor Harris in 1967. The researchers gave people texts, some of which opposed Fidel Castro and some of which supported him. Most subjects said the writers held the beliefs expressed in the essay, even after the experimenters told them that an instructor or experimenter had previously dictated the essay's stance to the writer. The point is that the subjects did not take into the account all of the situational factors when making a decision about the writers' attitudes.

Intuition is not always wrong. Expert chess players, for example, develop extraordinary speed in making moves, and learn to instantly recognize the available moves and strategies based on the board. Team sports players operate in much the same way.

There are, however, limits to what intuition can offer. Experts say it's important to distinguish between decisions that should be made by intuition and those that require careful calculation.

"With respect to accuracy, it all depends on the nature of the decision. I would not rely on my gut judgment when picking stock options for my retirement portfolio, for example," said Alexander Todorov, assistant professor of psychology and public affairs at Princeton University.

Some of the most remarkable mental feats are done entirely without awareness, such as color vision, said Eldar Shafir, professor of psychology and public affairs at Princeton University. Other tasks require more effort, with less impressive results -- for example, humans can't navigate as well as a honeybee, which has a brain the size of the head of a pin.

Todorov and Shafir both said the conclusions of Pouget's moving dot study -- that people make good decisions about certain perceptual problems -- make sense.

"We -- like every other biological organism -- do some things remarkably well, and often unbeknownst to us. Other things, we do remarkably badly, even if we might think -- sometimes with great confidence -- otherwise," Shafir said.


Saturday, January 10, 2009

Are you racist?

Reactions to racism not as strong as we think, study finds
While most people believe they would not tolerate a racist act, a new study from Canadian and U.S. researchers found test subjects in an experiment reacted with indifference when exposed to one.

Researchers in Toronto recruited 120 non-black York University students for what they said was a psychology study.

Half of the students were each put in a room with two actors - one white and one black - posing as other participants of the study.

The black actor then left the room to retrieve a cellphone, lightly bumping the other actor on the way out.
The white actor then responded in one of three ways:

- saying nothing
- saying the phrase "I hate when black people do that" or
- uttering an offensive racial slur.

When the black actor returned, study participants were asked to fill out a questionnaire rating their emotional mood and then were asked to choose a partner for what they thought was the actual test.

The researchers found that in cases where the white actor made a racist comment, participants did not speak out, did not report any emotional distress and actually chose the white actor as a partner more often than they did the black actor.

These results stood in stark contrast to a second group of respondents who were asked who they would choose as a partner after having the situation described to them.

These respondents overwhelmingly chose not to work with the white actor when a racist statement was uttered.

Lead researcher Kerry Kawakami, a psychology professor at York University, said the study raises awareness that even people who consciously condemn racism might harbour implicit biases. (CBC radio's Quirks and Quarks will have an interview with the study's lead author today, Jan. 10th)

"People should be aware that maybe they have this duality inside themselves," Kawakami told CBC News. "They think they're egalitarian, they think they're fair, they think they'll react in negative ways towards racism, but that might not actually be the case."

In an accompanying analysis in Science, psychologists Eliot R. Smith from Indiana University and Diane Mackie from the University of California, Santa Barbara, suggest another reason the participants may have reacted to the incident with indifference.

Since they were knowingly participating in a test, they behaved in manner previous research has suggested experiment participants often do: that is, constraining normal impulses in an effort to be helpful and focused on what they believe to be the task.

Smith said the study illustrates that in certain social contexts, it may be easy for people to dismiss a racist remark as an oddity. Those social contexts extend beyond the role of experiment participant.

I'd like to get the thoughts of my readers on this study...what are your opinions on the findings?

"The failure of people to confront or do anything about racist comments is pretty widespread in the real world," said Smith. "People may feel uncomfortable if someone makes a remark like this, but it's rare they will actually confront them."

Researchers from the University of British Columbia and Yale University also co-authored the study.