The men who robbed her likely chose Lisa because she unknowingly sent out signals that marked her as a "soft" target. Alone and encumbered by a backpack, she appeared to be a vulnerable person who could be easily controlled. "Some of these guys concentrate on people who are easy to overcome," says Volkan Topalli, a psychologist and at Georgia State University. "They'll target females, they'll target older people, but they're also looking for cues of weakness or ."

Criminals, like their victims, come in all varieties, but researchers have found that they don't choose their victims randomly. There's a reason FBI agents begin crime investigations by creating profiles of victims. It's because the of victims—particularly if there are several victims with differing characteristics—helps investigators determine whether a criminal is targeting a specific kind of person or choosing victims opportunistically.

In the field of victimology, one of the central concepts is that of the "risk continuum"—there are degrees of risk for a type of crime based on your , lifestyle, relationships, movements, and even , aspects of which are manifest in your behavior and demeanor. Some factors that make people potential victims are obvious—flashing wads of cash, wearing expensive jewelry, walking alone on back streets. Others are subtler, including posture, walking style, even the ability to read facial expressions.

The cues add up to what David Buss terms "exploitability." An evolutionary psychologist at the University of Texas, Buss is examining a catalogue of traits that seem to invite some people to exploit others. There's cheatability (cues you can be duped in social exchange), sexual-exploitability (cues you can be sexually manipulated), as well as mugability, robability, killability, stalkability, and even sexual-assaultability. "As adaptations for exploitation evolved, so did defenses to prevent being exploited—wariness toward strangers, cheater-detection sensitivities, and possibly anti-rape defenses," explains Buss. "These defenses, in turn, created selection pressure for additional adaptations for exploitation designed to circumvent victim defenses. This co-evolutionary arms race can continue indefinitely."

Nowhere does victimology imply that people who stand out as easy targets are to blame for becoming victims. Predators bear sole responsibility for the crimes they commit—and should be held accountable and punished accordingly. Moreover, many attacks are random, and no amount of vigilance could deter them. Whether victims are selected randomly or targeted because of specific characteristics, they bear no responsibility for crimes against them. But by being aware of which cues criminals look for, we can reduce the risk of becoming targets ourselves.

What You Don't Know Can Hurt You

In a classic study, researchers Betty Grayson and Morris I. Stein asked convicted criminals to view a video of pedestrians walking down a busy New York City sidewalk, unaware they were being taped. The convicts had been to prison for violent offenses such as armed robbery, rape, and murder.

Within a few seconds, the convicts identified which pedestrians they would have been likely to target. What startled the researchers was that there was a clear consensus among the criminals about whom they would have picked as victims—and their choices were not based on , race, or age. Some petite, physically slight women were not selected as potential victims, while some large men were.

The researchers realized the criminals were assessing the ease with which they could overpower the targets based on several nonverbal signals—posture, , pace of walking, length of stride, and awareness of environment. Neither criminals nor victims were consciously aware of these cues. They are what psychologists call "precipitators," personal attributes that increase a person's likelihood of being criminally victimized.

The researchers analyzed the body language of the people on the tape, and identified several aspects of demeanor that marked potential victims as good targets. One of the main precipitators is a walking style that lacks "interactional synchrony" and "wholeness." Perpetrators notice a person whose walk lacks organized movement and flowing motion. Criminals view such people as less self-confident—perhaps because their walk suggests they are less and fit—and are much more likely to exploit them.

Just like predators in the wild, armed robbers often attack the slowest in the herd. People who drag their feet, shuffle along, or exhibit other unusual gaits are targeted more often than people who walk fast and fluidly.

That criminals are attuned to cues of vulnerability makes sense given that most criminals, especially murderers, are looking for people who will be easy to control. Even rape is motivated less by and more by the desire for control and power.

Sexual predators in particular look for people they can easily overpower. "The rapist is going to go after somebody who's not paying , who looks like they're not going to put up a fight, who's in a location that's going to make this more convenient," says Tod Burke, a criminologist at Radford University in Virginia.

"If I had the slightest inkling that a woman wasn't someone I could easily handle, then I would pass right on by. Or if I thought I couldn't control the situation, then I wouldn't even mess with the house, much less attempt a rape there," says Brad Morrison, a convicted sex offender who raped 75 women in 11 states and who's quoted in Predators: Who They Are and How to Stop Them, by Gregory M. Cooper, Michael R. King, and Thomas McHoes.

"Like, if they had a dog, then forget it. Even a small one makes too much noise. If I saw a pair of construction boots, for example, out on the porch or on the landing, I walked right on by. In fact, I think if women who live alone would put a pair of old construction boots—or something that makes it look like a physically fit manly-type of guy lives with them—out in front of their door, most rapists or even burglars wouldn't even think about trying to get into their home."

Distraction is another cue criminals look for. Some people think talking on a cell phone enhances their safety because the other person can always summon help if there's trouble—but experts disagree. Talking on a phone or listening to an iPod is a distraction, and armed robbers are casting about for distracted victims. "Not paying attention, looking like a tourist—having the map out, looking confused—absolutely makes people more vulnerable," Burke says.

Being aware of your surroundings, however, may not help much if you don't know what to pay attention to. James Giannini of Ohio State University discovered something shocking: Women who are the victims of rape tend to be less able than average to interpret nonverbal facial cues—which may render them oblivious to the warning signs of hostile intent and more likely to enter or stay in dangerous situations.

The same team also found that rapists tend to be more able than average to interpret facial cues, such as a downward gaze or a fearful expression. It's possible this skill makes rapists especially able to spot passive, submissive women. One study even showed that rapists are more toward women than other criminals—although they have a distinct empathy gap when it comes to their own victims. A highly attuned rapist and a woman who's oblivious to hostile body language make a dangerous combination.

Even personality plays a role. Conventional holds that women who dress provocatively draw attention and put themselves at risk of . But studies show that it is women with passive, submissive personalities who are most likely to be raped—and that they tend to wear body-concealing clothing, such as high necklines, long pants and sleeves, and multiple layers. Predatory men can accurately identify submissive women just by their style of dress and other aspects of appearance. The hallmarks of submissive body language, such as downward gaze and slumped posture, may even be misinterpreted by rapists as .

Drinking and drug use, not surprisingly, also mark a person as a potential victim. "It's a robber's dream to knock a drunk down and take what they've got," says former Ohio detective Stacy Dittrich.

That goes double for sexual assault. Drunken people not only appear more vulnerable, they're also especially likely to place themselves in dangerous situations. decreases people's ability to evaluate the consequences of their actions and distorts their ability to predict how others perceive them. And women who are intoxicated, studies show, tend to be animated, giving off signals sexual offenders may misinterpret as sexual interest.

The Resentment Motive

Many armed robbers have a chip on their shoulders and view life as inherently unfair, says criminologist Richard Wright, a professor at the University of Missouri at St. Louis and co-author of Armed Robbers in Action: Stickups and Street Culture. As a result, they often see someone else's success as a reminder of their own failure and inferiority. Worse still, they interpret outward signs of another's prosperity as a personal affront. "When they see people flaunting their wealth or driving fancy cars, they see that as an attempt to put them down," Wright says.

For this reason, robbers are especially apt to target people who are flaunting material possessions or even just displaying a cocky, superior attitude. Street predators have their own word for such behavior—"flossing"—and it infuriates them. "It's a very visible reminder of their situation," Wright adds, "of being poor, that they've got nothing in their pockets."

From the perspective of the perpetrator, the robbery balances the scales, at least temporarily. "It's a restoration of justice," Wright explains. "'You were putting me down. Now guess what? I'm going to put you down. You've got all that. I'm going to take it away.'"

Sometimes, however, indignation may be just moral flimflam robbers use to justify their own behavior. "In some cases, offenders need to manufacture to commit the crime," Topalli says. Somehow, they need to justify their actions. "It's better to rob people who deserve it."

In the inverted universe that resentment builds in the brain, many armed robbers view themselves as the real victims in the world, a world in which the rich take their wealth from the poor.

Reducing the Risk

Grayson, co-author of the classic study on body language and exploitability, believes people can be taught how to walk in a confident way that reduces their risk of assault. To reduce the chances of becoming a victim, you can't look like a victim. "Walk in an alert fashion, walk with purpose, with your shoulders held back," advises Topalli.

Even better, avoid placing yourself in dangerous situations and stay aware of your surroundings at all times. Location is a key factor in street crime, particularly in cases of sexual assault. Criminals prefer sites that are likely to serve up few witnesses and little chance of being caught. Plan routes that avoid such locations.

And while you're at it, don't even talk to strangers on the street in isolated locations. One warning sign that you may be about to be robbed or attacked is the approach of a stranger on the street. The person may try to engage you in conversation. He may ask for the time, directions, bus fare, or try to tell you about a nice club or restaurant just around the corner.

Calvin Donaldson, who's been in prison in Louisiana for the last 28 years after robbing a couple in the French Quarter who asked him for directions, offers some advice: "Once you stop and let this guy engage you in conversation, you're opening yourself up," he says. "Some people you don't talk to. You just keep going."

How do you survive unharmed if you find yourself targeted? Cooperate. "They're not going to hurt you unless they need to," says New Orleans Police Department psychologist James Arey. Convicted armed robber Darryl Falls, who admits to committing more than 100 robberies, agrees. "The quicker you comply and give them your goods," he says, "the quicker they're out of your face."

Some of Falls' victims tried to conceal jewelry to which they had an emotional —wedding rings, for example. "I understand the sentimental value," he says. "But you can get that back. You can't get your life back."