Wray Herbert has written about psychological science and mental health for many years.

Malcolm Gladwell has written several best-selling books since “The Tipping Point” in 2000, and by now his method is well known. He begins by translating a body of psychological research into breezy prose, then draws connections to contemporary and historical events that demonstrate the psychological principles in action. Depending on the reader, these connections are either entertaining and insightful or wild and tendentious, even misleading. “Talking to Strangers,” Gladwell’s exploration of deception and misunderstanding in human communication, is sure to find both types of reader.

Gladwell is impressive in his range of historical conundrums. Why, he asks, was British Prime Minister Neville Chamberlain completely bamboozled by Adolf Hitler when, in 1938, the rising German leader assured Chamberlain of his benign intentions in Europe? Why did so many intelligent investors trust their fortunes to scheming financier Bernie Madoff? Why are we so bad at understanding suicidal thinking? How do missed signals about desire and intimacy turn into date rape? Why are highly trained intelligence officers often oblivious to spies in their ranks? And, most compelling to Gladwell, why does community policing so often go awry, leading to tragedy?

These fascinating puzzles, and many others, add up to what Gladwell labels the Stranger Problem. We are constantly interacting with people whom we don’t know well, if at all, and Gladwell believes that our psychological clumsiness in these situations leads to all sorts of misunderstanding and heartache. He devotes fully three chapters to the work of Tim Levine, an expert on deception, to illuminate our ineptitude when encountering strangers. For example, one of the fundamental psychological concepts to emerge from Levine’s deception studies is “default to truth.” Given the choice to believe a stranger or not, humans tend overwhelmingly to believe, to trust, to give the benefit of the doubt. This is counterintuitive. It doesn’t make any sense, from an evolutionary point of view, that the human mind would be biased toward such a generosity of spirit; suspicion and mistrust would seem to be much more adaptive in a dangerous world. Yet Levine’s results, according to Gladwell, are unassailable; everyone from FBI agents to lawyers to intelligence workers opts to believe rather than to question strangers’ claims.

This powerful cognitive bias is reinforced by other psychological tendencies that make it even harder to get a good read on strangers’ intentions. Most notably, the author argues, humans expect strangers to be transparent, to reveal their thoughts and emotions in their demeanor, body language and actions. But they don’t — not reliably. People who are nervous and sweaty and otherwise guilty-looking are just as likely to be telling the truth as they are to be lying. And the cool and collected may simply be good at the confidence game.

This “mismatch” is the source of many misunderstandings. Consider the case of Amanda Knox, an American studying in Italy who was falsely accused of murdering her roommate. She ended up spending six years in prison before being acquitted and released; her only crime was not acting contrite, being too cheerful in the midst of a murder investigation. Or consider Madoff, who had a style that was trustworthy and reassuring, even while he was stealing millions of dollars from investors. His tone and manner were a psychological mismatch with the greedy and felonious mind at work below the surface.

Gladwell is especially interested in the psychology underlying failures of community policing. Indeed, he begins and ends this book with the sad case of Sandra Bland, quoting extensively from the public record to support his analysis. Bland was a young black woman from Chicago who was in Prairie View, Tex., for a job interview when she was pulled over by a white police officer, Brian Encinia, for not signaling a lane change. It was a routine, minor traffic stop, and should have stayed that way, but it escalated and escalated. In the end, Bland was arrested and thrown into jail, where she committed suicide three days later.

Gladwell’s exhaustive analysis of the Bland case is unconvincing and troubling. He wants to link this tragic encounter to Encinia’s paranoid style of policing, a nationwide trend among officers rooted in the cognitive biases he discusses. But in arguing his case so single-mindedly, Gladwell seems naively oblivious to a more obvious reason for this tragic encounter: racism. It’s not that cognitive biases don’t play a part, even an important part, but racist attitudes and practices seem a much more likely explanation for this incident.

Similarly, Gladwell dances around the topic of torture in his chapter on Khalid Sheikh Mohammed, a 9/11 mastermind whose deceptions the CIA uncovered in its interrogations. He presents this case as the “most extreme version of the talking-to-strangers problem: a terrorist who wants to hold on to his secrets, and an interrogator who is willing to go to almost any lengths to pry them free.” Yet in the end, this example has little to do with the stranger problem or psychology, and everything to do with waterboarding and sleep deprivation. He explicitly sidesteps the ethics of torture to keep his analysis tidy, yet in the end his case study is too tidy to ring true.

If Gladwell is right, if we are by nature too naively unquestioning, if that’s the core of the Stranger Problem, what’s the solution? How do we muster a bit more skepticism and keep from being conned? How do we get a proper read on others’ intentions in our myriad daily encounters with strangers? There are no hard lessons here, but the conclusion seems humane. Not by compensating with cynicism and fear, Gladwell says; that only leads to a society of paranoid cynics. Being overly trustful may have unhappy consequences at times, the author concludes, but abandoning trust as a defense against predation and deception is worse.

Talking to Strangers

What We Should Know About the People We Don't Know

By Malcolm Gladwell

Little, Brown.
386 pp. $30