The Out-of-Sight Mind

By SUSAN PINKER

THE HIDDEN BRAIN

How Our Unconscious Minds Elect Presidents,

Control Markets, Wage Wars, and Save Our Lives

By Shankar Vedantam

270 pp. Spiegel & Grau. $26

Invisible forces that control our behavior have inspired our best storytellers, from Euripides to Steven Spielberg.. Whether we’re yanked around by jealous gods, Oedipal urges or poltergeists, the idea that we feel powerless to direct our own actions has a visceral appeal, one exploited by Shankar Vedantam in “The Hidden Brain,” his exploration of the unconscious mind.

Most previous popular treatments of subliminal forces haven’t been data driven. Vedantam, who until recently wrote the Department of Human Behavior column for The Washington Post, hopes to fill that gap. His entertaining romp through covert influences on human behavior began as a series of columns, and true to its genesis, it reads as vivid reportage overlaid with a sampling of science. Ranging widely from the role of social conformity in violence to snapshots of racial and gender prejudice, Vedantam draws expansive arcs between findings from social psychology and the nation’s sensibilities and voting patterns. “Unconscious bias reaches into every corner of your life,” he writes, thanks to a “hidden brain” generally inaccessible through introspection. As with crop circles, all we see are the traces left by covert attitudes, never the perp at the scene of the crime.

Colorful characters form the backbone of the narrative; we meet a bickering, long-married academic couple, a rapist with great teeth, a woman working the night shift at a tire factory, a woman suffering from a rare form of dementia and a cult member. What binds this motley crew together? All are victims of some form of irrationality — those imperceptible forces that often prompt our actions in the real world, the ones that are at odds with our ideals.

Most of us assume that honesty and generosity are personality traits polished over a lifetime of social interaction. But Vedantam shows how imperceptible social signals determine, for example, how deeply you’ll dig into your pocket. In offices with an honor system for coffee, people are more likely to pay on days when a photograph of human eyes is discreetly posted above the coffee machine, according to one British study. They’re more prone to cheat if a still life of daisies is pasted there instead — even if they say they’re unaware of either picture. Another experiment demonstrates that you’re likely to give a handsome tip to a waiter who repeats your food order verbatim. In fact, you’ll tip an average of 140 percent more than you would if he just paraphrases it. It’s all about social mimicry, apparently, our hidden ability to sync our behavior with the group’s.

While social cues grease the wheels of interaction in subtle ways, they can also create hazards. In a gripping chapter on disasters, Vedantam describes the snap decisions made by employees of one brokerage firm in the south tower of the World Trade Center in the crucial minutes after the first plane hit on Sept. 11. The group on the 89th floor reached the consensus that they were not in danger — and perished. The group on the 88th floor ran for the stairs and survived. While everyone felt they were making autonomous decisions, the decisions were really made by the group. “Group decisions provide us with a signal,” Vedantam writes. “The details about individuals — who did what, who felt what, who thought what — is noise.” He cites another analysis, of response to the 1993 World Trade Center bombing, in which two different groups escaped at different rates. What mattered wasn’t what floor the groups were on but how large they were. “Groups seek to develop a shared narrative as an explanation for what is happening,” Vedantam writes. “The larger the group, the longer it took to arrive at a consensus.” His conclusion? “People can undermine themselves — and reduce the overall survival rate — by trying to help one another.”

The crisis vignettes are skillfully spun out, Grisham style. Vedantam presents a fresh, bracing case for the dangers of group-think. But he sometimes extends his lessons too far. While Vedantam is right that large groups tend to produce fewer good Samaritans, studies of social networks show they can also mobilize quite effectively. After Hurricane Katrina, an impromptu “Cajun navy” rescued thousands of stranded residents. And a number of sociologists have documented how hundreds of thousands of people were evacuated from Lower Manhattan on Sept. 11 by another spontaneous armada.

In a chapter on the psychology of suicide bombers, Vedantam draws parallels among obsessed sports fans, a Jonestown crackpot, violent extremists and striving executives. “The hidden brain’s drive for approval and meaning, and the ability of small groups to confer such approval and meaning, is what is common to the world of” all four, he writes. Social “tunnels,” which block out input from the outside world, direct some people toward public service and heroism, others toward violence.

True, we all want to belong. But the evidence Vedantam offers for his claims is often too scant or streamlined, with contradictory or ambiguous results and dissenting interpretations left out. Meanwhile, the biggest bias of all — confirmation bias, which makes us notice only what supports our own opinions and tune out everything else — hardly gets a mention. All this secret stuff can be very disconcerting. But we need more than we get here to know if it is true.

Susan Pinker is the author of “The Sexual Paradox: Men, Women and the Real Gender Gap.”

http://www.nytimes.com/2010/01/17/books/review/Pinker-t.html?ref=books