I broke up with a guy I was dating after discovering he'd lied about his age on the dating app we'd met on. (He's 48, not "39.") I'd told him honesty's a big deal for me. He claimed he's honest with those he cares about and at work and argued that everybody lies on dating sites. I'm not buying that. Isn't someone either honest or not?

--Skeptical

There's that saying, "act your age," and he is -- as a guy cresting 50 who wants a girlfriend who still sometimes gets carded.

Chances are you consider yourself an honest person. But you're not. None of us is. In the words of TV's Dr. House, "Everybody lies." Social psychologist Bella DePaulo concurs. In her research on lying, she explains that people can't be "tossed into one of two moral bins, one for the people who are honest and the other for the liars."

In fact, we all lie in ways we don't even recognize as lies. Do you wear control-top tights or Spanx? A push-up bra or a squish-you-down bra? How about under-eye concealer? (Note that it isn't called under-eye revealer: "All the better to show off my ginormous, dark, puffy eyebags!")

These less-than-truthful forms of self-presentation are a lighter shade of the lie this guy told: an "instrumental" lie -- a lie used as an "instrument" to get others to give us "material rewards or other personal pleasures or advantages" they wouldn't if we told the truth.

But consider that people who don't lie their way through life might see lies in an online dating profile as sort of Spanx-type fibbies: a way to game an unfair system, a la, "I'm so much younger than my real age, and the hot young women I want would see that -- uh, if only I could get around their searches where they cut out my age group."

Getting a realistic sense of a man's true character probably takes listening and watching over time, especially when he doesn't know you're doing it. That should help you avoid missing out on good guys who occasionally retrofit the truth with a little Spandex. And you'll know to ditch those who are ethically iffy -- or worse: for example, some other 48-year-old dude who has the firm body of a man half his age -- and if he keeps it in his basement freezer, no one will be the wiser.

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.

I'm a senior in college, and the woman I recently started seeing is a sophomore. My buddies told me she has a "reputation," as in, she's hooked up with half the men's soccer team. She's beautiful and intelligent, and I don't understand why she has the low self-esteem to behave that way.

--Rethinking Our Relationship

Turn the tables, and imagine a guy who's hooked up with half the cheerleading squad. Your first thought: "Dude must have a huge..." (and correct me if I'm wrong) "...set of mommy issues."

There's a pervasive stereotype (held by both men and women) that women who engage in casual sex have low self-esteem, explains evolutionary social psychologist Jaimie Arona Krems. The underlying assumption: Women who have casual sex don't really want it; they're just settling for it. However, Krems and her colleagues find that this insulting stereotype persists even when women are "explicitly described as choosing to have casual sex."

The researchers surveyed participants (about their own self-esteem and their perception of others') using the generally accepted definition of self-esteem: "feeling good about oneself and having a solid sense of one's self-worth." The stereotype -- that women have casual sex because their self-worth is in the dumpster -- "appears to be unfounded." (Women's "sexual behavior was not significantly correlated with their self-esteem.")

They speculate that the stereotype might stem from evolutionary "mismatch": our living in a modern world with a sometimes-outdated psychological operating system. The psychology guiding us today evolved back when locked knees were the only reliable birth control. It would've served ancestral women with high mate value -- those with their pick of men -- to hold out for commitment before having sex (and possibly offspring) with a man. Thus, we might have "default assumptions that women pursue casual sex only when committed sex is unavailable to them." (In simple terms, despite all the birth control technology of today, the dial of human psychology is still set to "slut shaming.")

As for your situation, assuming the rumors aren't just "guy-perbole," maybe your girlfriend worked her way through the soccer boys not because she's a human broken toy but because she's hot, enjoys sex, and wanted some naked fun while looking for her Mr. Boyfriend. What does this say about her? Well, after the initial steamy phase of the relationship, the sort of animal she's most like in bed probably won't be shrink-wrapped supermarket salmon.

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.

I'm a guy in my senior year of college. I cannot figure out how my roommate gets all the women he does. He's a huge jerk to everyone, including women -- the typical "bad boy." He breaks any rule or law he can, doesn't care who he hurts, and makes very little effort with women, yet all my female friends go for him. A good friend (sleeping over, as it got really late) even left my bed in the middle of the night to get into his! Why?!!

--Nice Guy

Women -- especially in their 20s -- will blather on about how they want a nice, reliable guy. Then they find one and immediately despise him for how nice and reliable he is: like how he always calls when he says he will -- usually to the minute! -- and there's never that recorded voice on the line first, "Will you accept a collect call from prison?"

Reading between the lines of your email, you seem to have the same question cognitive scientist Scott Barry Kaufman asked: Basically, do you have to be a jerk to get the girl? To answer that, Kaufman explored bad boys' appeal. He observes that bad boys tend to have big helpings of "dark triad" personality traits. Dark triad sounds like the name for three ne'er-do-well superheroes, but it's actually the term for three malevolent personality traits with some ugly similarities: Machiavellianism, psychopathy, and narcissism.

Machiavellianism, named for 16th-century Italian political adviser (aka tyrant whisperer) Niccolo Machiavelli, plays out in ruthless scheming, callousness, and self-interest. Psychopathy shows itself in callous detachment, poor impulse control, and a lack of empathy and remorse. Narcissism is reflected in egotism, an extra-large sense of entitlement, a lack of empathy, and "grandiosity": an inflated sense of one's greatness in contrast with all the rest of the human worms.

This is quite the personality poison pack, yet -- in research mirroring your experience -- evolutionary psychologist Peter K. Jonason found that dark triad traits were correlated with having more sex partners (as well as more of a desire for hookups).

Obviously, the dark triad traits themselves -- essentially heartless, exploitative user-ishness -- make exactly no one in their right mind go, "Wow, where do I sign up for somebody with all that?!" However, Kaufman observes that dark triad "bad boys tend to have lots of positive traits that come along for the ride (with) the badness," such as confidence, assertiveness, and fearlessness, along with creativity, humor, charisma, and high energy -- "all things women find attractive."

I think two types of women are particularly drawn to bad boys: hookuperellas -- women who just want casual sex -- and "sensation-seeking" excitement junkies. Sensation seeking is a personality trait that psychologist Marvin Zuckerman finds plays out in a craving for novel, varied, intense sensations and experiences and a willingness to take risks to get them.

There's a clue in all of this for the dismayed nice guy who can't understand why women seem to fall out of the trees into bed with the jerk. Even women who aren't danger-and-excitement junkies are drawn to men who are a consistent source of "novel" experiences: that is, who never stop surprising them (though playfully rather than evilly!).

Also, consider that what drives away women isn't so much being a nice guy but an overly nice guy: a guy who comes off needy, tentative, and desperate to be wanted. Now, maybe you feel needy, tentative, and desperate -- at least to some degree. (Who doesn't?!) The thing is there's no mandate for you to act the way you feel. That said, I explain in "Unf*ckology" that "fake it till you make it" is actually a bust, because you typically succumb to "cognitive overload": you have so many things to remember (to come off confident, surprising, fun, etc.) that you end up getting overwhelmed and falling apart.

I instead advise that you "impersonate your way" into the new confident you: basically, borrow a confident, easygoing, fun guy's persona -- meaning, secretly "be" him (like an actor playing a role) when, say, talking to a new woman in a coffee shop. Do this repeatedly, and you should see that women treat you very differently.

There are sure to be some hiccups, but you should eventually feel ready to do this confident, easygoing thing as you: a nice guy who's trained himself into having the good parts of bad-boy mojo. By the way, you should have an easier time with the ladies as you approach your 30s because many women will have been jerk-burned at least once and learned their lesson. They want a guy who can hold their attention for hours with his wit and good nature -- as opposed to the dude who seems destined to hold off the cops for hours by shouting demands from inside the 7-Eleven.

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.

I'm envious of a friend whose boyfriend frequently does nice things for her: bringing her soup when she's sick and surprising her with a weekend getaway and a pricey handbag she'd been coveting. My boyfriend is a nice, reliable, loving guy. I'd considered myself lucky to have him, but now I'm worried my "good-boyfriend" standard is too low.

--Comparison Shopping

A woman feels loved when the man she's with does those little things that say "thinking of you" -- as opposed to "spent all day forgetting I had a girlfriend."

Not surprisingly, you envy your girlfriend who gets those little (and bigger) signs. Envy gets a bum rap as a toxic emotion. (It can have toxic effects when the envious try to even things out by sabotaging those doing better.) However, evolutionary social psychologist Bram Buunk's research suggests envy is actually "adaptive": functional -- a sort of alarm clock for yearning and ambition, alerting us to others' higher achievements (or groovier stuff) and motivating us to nab the same (or more) for ourselves.

Men are not cryptographers, and they are particularly bad at translating women's nonverbal signals like pouting -- if they notice them at all. Tell your boyfriend what you want -- sweetly, not scoldingly -- in the context of "what would make me really happy." Chances are you'll need to tell him a few times to get him to come around. When he does, reinforce future come-arounds by telling him how happy he's made you, how much it means to you. (Doing this while tearing off his clothes, if you're so inspired, should make an even stronger impression.)

But say, even with reminders, your boyfriend drops by with soup or a latte just once and then forgets the whole deal. Sure, you could put him out with the recycling for some woman with lower "good-boyfriend standards" to pick up. However, you might reflect on ways he shows he cares: maybe giving you his coat when you're cold or fixing your car so you won't die in a fiery wreck. You might also consider that some men's apparent generosity reflects not love but the sense they're out of their league. If that's the case with your friend's boyfriend, the stream of soup, swag, and trips is just a campaign to delight-slash-distract her from dumping him -- a la, "Never put off till tomorrow goods-and-services-izing what could be in some other dude's arms two Thursdays from now!"

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.

I had a nice first-date dinner with a guy I met on a dating app. Afterward, he said he had something to show me, pulled up his pant leg, and revealed an ankle monitor! He said he hadn't wanted to put it on his dating profile, and "It was just white-collar." (I Googled. Embezzling money. He's on "supervised release" -- apparently with some range beyond house arrest.) This situation bothered me, but I accepted his invitation for a second date, given our chemistry.

Ideally, if a man wears "statement jewelry," the statement it's making isn't: "I'm in constant communication with my parole officer."

A guy who embezzles money -- assuming there's no "my brain tumor made me do it!" -- is likely low on the personality trait of conscientiousness. Someone high in conscientiousness is disciplined, dependable, organized, and shows concern for others' needs and feelings. In contrast, those short on conscientiousness are unreliable, careless, impulsive, and poor at delaying gratification. (They probably see little reason to do it, as they also have an "eh, whatevs!" attitude about their effect on others.)

Personality traits tend to be pretty stable over time and in various situations -- though research by psychologists Nathan Hudson and R. Chris Fraley suggests people can work to change their personality by repeatedly changing their typical behavior. For example, a usually inconsiderate guy could act like a person high in conscientiousness, starting in small ways, like making the bed every morning instead of leaving it for the girlfriend-slash-housekeeper to do. That said, lasting change might not be possible without strong motivation to mend one's ways -- like feeling deep remorse at all the people one hurt. (Remorse at getting caught doesn't count!)

This guy's "it was just white collar!" is not exactly dripping with contrition. You could get him on the phone before your date to probe further into what he did and his current perspective on it. Is he passionate about turning over a new leaf, driven to be honest -- or just to seem honest? As for your "chemistry!" argument for seeing him again, consider that you get the whole dude, not just the hot parts. Wanting to see the best in somebody doesn't make the worst in them disappear. It just might be a while before you arrive home early and spot it -- in bed with your best friend, your sister, and the UPS lady.

For pages and pages of "science-help" from me, buy my latest book, "Unf*ckology: A Field Guide to Living with Guts and Confidence." It lays out the PROCESS of transforming to live w/confidence.