I'm a woman in my 20s. Some stuff in my life was going really wrong, and I got depressed. I didn't tell people, but it had to be obvious. I distanced myself from my group of girlfriends, meaning I missed birthday parties, didn't respond to group texts, and was overall not a great friend. Still, I did what I could, like taking a friend for a spa day after missing her birthday the week before. Weeks later, I learned she was still harboring resentment that I had missed her birthday. Don't I deserve a bit of a break?

--Feeling Better Now

On the day of your friend's birthday, you felt like quite the party animal -- if, by "party animal," we mean "rat lying cold and dead in the corner of the cage."

Depression gets a bad rap. It can be a terrible, dysfunctional thing when it's caused by brain abnormalities or persists without end. However, psychiatrist Randolph Nesse explains that human emotions, including the feelbad ones, are psychological programs that evolved to solve recurring mating and survival issues. When you're mired in frustrating, unrewarding endeavors, symptoms of depression like sadness, hopelessness, and fatigue appear to have a function. They slow you down, plant you on the couch, and force you to rethink and change unworkable situations in your life: dump that jerk, stand up to your boss, fake your death and move to Croatia.

Sadness is also a strong social signal. When we see someone's sad, we're motivated to comfort them (or at least cut them some slack). In an ancestral environment, countless centuries before apartments with locking doors, your friends would have noticed you were depressed. In a modern environment, suffering often remains hidden. In other words, it's possible this woman and your other girlfriends assumed you were socially sloppy, inconsiderate, and a bad friend -- instead of understanding that you were a friend in need.

Take stock of the girlfriends around you and figure out whom you can trust to be real friends to you: those you can show who you really are, including all the sobby parts. Friends like that will mop up for you socially (in tactful ways) at times when your answer to, "Hi, how are you?" is likely to be: "Actually, I'm going to die alone, and then nobody will discover the body until the UPS guy comes to the wrong house and nearly keels over from the smell."

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 31-year-old woman, and I recently started dating a guy about my age. We've gone on five dates, but we haven't had sex, as I wanted to take things slowly. He's been okay with that, but I'm quite certain he's sleeping around elsewhere. I hate the idea of him having sex with other women. Still, we aren't at the level of being committed, and I'm not comfortable having sex with him yet. What do you recommend I do?

As you see it, the free-range penis should be more like those factory-farmed chickens.

The "hate" you describe feeling at the idea of him having sex with other women is actually jealousy -- specifically, "sexual jealousy": a stew of dark emotions (including humiliation, rage, despondency, and grief) that gets activated by the perception that a romantic relationship is at risk. Jealousy gets sneered at as some sort of pathetic emotional immaturity that's to be avoided, a la "C'mon...be bigger than that." That advice is like telling the police to ignore alarms going off in banks, which, sure, are sometimes false, but can be a sign there's a cash transfer in progress -- to the duffle bags of three gun-brandishing dudes in Richard Nixon masks.

Like bank alarms, sexual jealousy has a vital function. It triggers "mate-guarding" behavior: tactics to fend off threats "to a valued romantic relationship" that could lead to "infidelity or abandonment," explains evolutionary psychologist David Buss. Mate-guarding tactics frequently used by women include "monopolization" (like bolting oneself to a partner at a party), "appearance enhancement" (hotting up to outdo any lurking competition), and "sexual inducement" (performing "sexual favors" to keep a partner around).

In other words, the discomfort you feel is a call to action loaded into you by evolution. But evolved motivations aren't behavioral mandates. Resolving to just suck up and ride out the discomfort seems the best way to avoid responding in ways potentially damaging to your long-term interests. Letting fear of loss drive you to have sex before you're ready could tag you with an air of desperation and/or cause you to confuse lust with love. Being gnawed by curiosity about the competition sometimes spins even normally stable and levelheaded women into crazycakes stalkers. Tempting as it might be to know whom you're up against, it's best a new fir tree doesn't suddenly appear outside the guy's apartment wearing the same go-go boots you do.

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.

What are your thoughts on women who are involved with much younger men? A friend who's my age, 58, is dating a 23-year-old guy. She started seeing him when he was 18 and refers to him as her "husband." I went on a day trip with the two of them, and it honestly felt like we had a child in tow. He whines and pouts to get his way, feels a need to one-up everybody in conversation, and says and does weirdly inappropriate things (like skipping through a graveyard and talking openly about his sexual prowess). They profess their love to each other often, and I guess if it's working, it's fine, but I just don't get it.

Dating somebody 40 years younger can make for awkward silences at dinner parties, like when somebody asks one's boyfriend, "What were you doing on 9/11?" and he says, "Um, teething?"

Of course, there are some constants in life, and one of them is how men, no matter how old and geezery, are most attracted to women in their early 20s. (Think Hooters hiring pool and 70-something grandpas with self-inflicted whiplash.) Women, on the other hand, tend to go for slightly older men throughout their lives, until they're in their 70s, when they dip down a bit -- though typically a handful of years, not four decades.

However, within every "men tend to" or "women tend to," there are individual differences; for example, a woman bumping up against 60 who's dating a guy who probably remembers preschool like it was yesterday -- because it kinda pretty much was.

Older women who date downward in age eight or more years (or try to) get called "cougars," sneering slang for sexually hungry older women hunting for younger man prey. The term is said to trace back to the Vancouver Canucks hockey team in the '80s: the players' label for older, single, hetero female groupies who frequented their games and tried to score sex with them. However, "cougar" didn't go wide till 2003, when Demi Moore, at 40, started dating the 15-years-her-junior Ashton Kutcher, then 25, whom she later married and divorced. There are now cougar reality shows, dating sites, blogs, and books, and there have even been cougar beauty pageants.

This makes it sound like there are hungry cougar-inas lurking around every corner. However, an analysis of census data by public policy researchers Zoe Lawton and Paul Callister in 2010 suggests the extent of this is "exaggerated by the media." They likewise suspect (and more recent survey data bears out) that the number of these older woman/much-younger man couplings that turn into long‐term relationships is "considerably smaller" than those that wind up as short-term flings.

Younger men are sometimes a workaround for older women experiencing a man famine: a shortage of men close to their age, who tend to date younger women. But a younger man can be (or turn into) a preference -- maybe because he's more fun and makes an older woman feel young again and probably because he's a sex machine that does not require pharmaceuticals or batteries. A much-younger boyfriend is also a status symbol of sorts, showily breaking the mold of being a sexually ignored aging woman. And maybe, just maybe, there's sometimes a connection that makes the guy's age and any related incompatibilities unimportant -- sometimes because an older woman is secure and happy enough on her own that she doesn't require a man to be a human Costco to fill her every need.

Though people point and laugh at older woman/younger man couples, the joke might be on the jokers. Social psychologist Justin Lehmiller surveyed around 200 heterosexual women in relationships: women with male partners close to their age, women significantly younger than their male partners, and women significantly older than their male partners (22 years older on average). He found that women 10 or more years older than their male mate were the happiest: the most satisfied with their relationships and committed to their partners.

The fact that your friend's been with this guy for five years suggests this is more than a Boytoys R Us phase. Ask her what she sees in him, and listen with an open mind. You might find your way to a little more compassion and understanding. That said, it's probably best to avoid being around the two of them and instead see her alone, because, well, adulthood can be overrated -- except when you want to have a conversation. Even if you never quite get what the attraction is, you might just resolve to be happy that she's happy. She's having fun; she's in love at nearly age 60; and sex for her is smokin' -- and not because her partner's pacemaker catches fire midway through.

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.

My girlfriend of a year is beautiful, intelligent, sweet, and loving and the first woman I could see having a future with. Last week, I was told I'm being laid off from my job at a large media conglomerate. I haven't told anyone, but I'm feeling increasingly guilty for keeping it a secret from my girlfriend. The thing is I'm afraid she'll think less of me, even if she pretends not to. To be honest, I'd rather break up with her than tell her.

--Distraught

Ideally, when you propose a date-night activity, it isn't a choice between: "We could go to the grocery store and look at all the food we can't afford to buy" or "to the bank with a sawed-off shotgun and a wheelbarrow."

However, your heartbreaking "I'd rather break up with her than tell her" probably stems from shortsightedness about female mating psychology. Because men and women co-evolved, men are acutely aware that women seek "providers" as partners. But, in ancestral times, when our current mating psychology was shaped, there was no such thing as wealth: assets that could be stashed (or places to stash them). No money, no banks, no corpse-sized freezer to cram 126 bison burgers into. Accordingly, evolutionary psychologist David Buss explains that women gauge a man's mate value by "looking beyond his current position" and evaluating his potential: his ability to acquire status and resources in the future. (Today, Top Ramen. Tomorrow, top surgeon.)

Assuming you didn't get your job because your boss threw darts at LinkedIn and hit you in the neck, you've probably got the smarts, talent, and ambition to get a new gig -- or start a business of your own. And chances are there's more to your relationship than two nice people hooking up on the regular. Cobble together the courage to be vulnerable. Tell your girlfriend what you're going through, including how you feel: perhaps scared, unsure of your value, and maybe like you've let her down. Sure, she might drop you like a hot rock -- but she might instead show you she loves you and believes in you, even when you're having a tough time believing in yourself. There's one way to find out which it is, and it isn't by spending two months keeping mum about the layoff while having pretend work calls on Zoom with your friend's dog.

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 woman in my 20s with a friend who often copies my style. It feels like she's trying to one-up me, but I've tried to ignore it. Well, for years, I've rimmed my lower eye with thick black kohl. She commented on it several weeks ago and then started doing it herself. At lunch yesterday, she said (about my eyeliner): "You started doing that? I've done it forever." This is the third time she's pretended my style she copied was hers first, but I feel petty being upset about it.

--Unflattered

Apparently, there could be two snowflakes that are alike -- from very tiny snow crystals -- but they probably wouldn't show up at the same bar wearing the same dress and eyeliner.

"Monkey see, monkey do" isn't limited to monkeys or stylejacking female friends. Even fruit flies are copycats, spotting an alpha ladyfly getting it on with a particular dudefly and, afterward, engaging in "mate-choice copying": the insect sex version of "I'll have what she's having!" Like fruit flies, we evolved to copy high-status peeps (friends and celebrities) to advance our evolutionary interests: survival, social survival, and our ability to mate and pass on our genes. Accordingly, evolutionary psychologist Abraham Buunk finds that envy is wrongly maligned as a toxic emotion. Sure, some envious people act in destructive ways ("malicious envy"), but simply noticing others outpacing us and feeling bad about it serves as an internal alarm system: "Hey, Slackerella...better catch up!"

We're told "imitation" is some fabulous form of flattery, so it can feel petty to accuse somebody of stealing your look. However, evolutionary psychologist Vladas Griskevicius explains that we try to make ourselves attractive to potential partners by seeming unique and special, standing out from the crowd. So, this woman's ultimately cheating in competing for mates, which is probably why she's "gaslighting" you. Gaslighting is a form of psychological manipulation in which somebody tries to destabilize your grasp on the facts by denying what you know is true, to the point where you might start questioning it yourself. In other words, what's creepy here isn't so much the crime as the cover-up. Probably the only way to stop this is dialing back her presence in your life. You can call the cops if somebody stabs you or steals your TV, but there are no actual fashion police to be dispatched, a la, "911, what is your emergency?" You: "Help! She plagiarized my eyeliner!"

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 girl in my early 20s, and I recently started dating a guy I met in college. I'm very happy, except for one issue: For as long as I've known him, he's followed Instagram accounts of attractive women with provocative photos (ranging from half-naked to entirely naked), and he'll "like" these pics. This really bothers me; however, I don't want to be the overbearing girlfriend. Why does he do this, and does it matter?

--Disturbed

There's a certain kind of man who's drawn to the sight of half-naked pert breasts, and it's the kind whose eyes have yet to be plucked out by crows.

This does not change when a man is in a relationship, even if he really, really loves the woman he's with. But many women believe that the eyes of a man in love wouldn't wander up and down other women and that being in a relationship should limit where eyeballs are allowed to travel: basically, You can't have your cake and look at other cake, too.

Men have perhaps 15 to 20 times the testosterone women do, and this seems to play a major role in how visually powered male sexuality is. An episode of NPR's "This American Life" featured Griffin Hansbury, who was born female and lived as a lesbian and then underwent sex reassignment surgery. Transitioning began with testosterone injections. Before starting testosterone, Hansbury would see a woman on the subway and think: "She's attractive. I'd like to meet her. What's that book she's reading?" With the testosterone injections, even noticing nice ankles on a woman flooded Hansbury's mind "with aggressive pornographic images. ... It was like ... a pornographic movie house in my mind. And I couldn't turn it off."

It's important to note that Hansbury overdid it on the testosterone injections at first, giving himself two to seven times the testosterone of the average male. So, the 24-hour porno mind Hansbury describes is probably seriously extreme compared with what goes through your boyfriend's mind. However, a general idea of what men experience points to why strip clubs for men are big business, while the few strip clubs for women are funny business: places they go not to get turned on but to haze a bride-to-be, laughing in her face at the giant flashing plastic vagina hat they've made her wear.

Ask a man why he eye-humps a woman, and if he's honest, he'll tell you it's because she's hot. But there's an underlying (subconscious) reason: "Evolution makes me do it." Because men only get pregnant in women's revenge fantasies, they evolved not to seek committed "providers" as partners as women do, but to prioritize physical attractiveness. We all like a nice view, but there's more to this preference than aesthetics. The features men find beautiful in women -- youth, smooth skin, pillowy lips, "neotenous" (aka childlike) features like big eyes, and an hourglass figure -- are correlated with fertility and health. In other words, men evolved to be drawn to women who look like really great candidates for passing on their genes.

Men's brains motivate them to stare at sexual eye candy in ways women's brains do not. In brain imaging research by psychiatrist and neuroscientist Hans C. Breiter and his colleagues, heterosexual men viewing attractive female faces showed increased activation in the brain's "reward regions": areas involved in the anticipation of reward (also activated by food, drugs, and money). The message to the man: "That's rewarding! Go get it!"

The good news is we are not mental robots, slaves to our urges. In most men, the brain's "go get it!" message simply leads to more looking, not nooners with the hot-erellas of Instagram. Some women consider looking cheating, and they tell their partner he's not allowed to eyeball other women. Chances are this doesn't stop the looking; it just turns men into sneaks and liars and their partner into the enemy they have to keep secrets from. You don't say that when your boyfriend's with you he goes rude and unloving: stops talking midsentence while his eyes hike up some underdressed woman's boobs. So, maybe you can use the strong biological and physiological basis of men's girl gawking to keep yourself from taking his Instagram sightseeing personally.

Consider that the guy set aside another strong evolved male preference -- the longing for sexual variety -- to be with you. In other words, being with you means a lot to him. Sure, he still spends time browsing in the online mall of naked and half-naked women, but browsing isn't buying. Assess whether he seems to be a good person, a person of character, and a guy who consistently shows you he loves you and has your back. If so, your best bet might be staying out of his browser history and recognizing that a little eye-humping doesn't mean there will be eye-penis coordination.

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.

Whenever I feel like I click with someone, I want to be upfront and tell them I like them right away. My friends all say this is dating suicide (and that's how it's been working out for me). But if I'm looking for emotional honesty in a partner, shouldn't I lead with it?

--Confused

If we're arrested, we have a right to remain silent. Ideally, we don't just confess: "That was me, robbing the 7-Eleven. See -- there on the video -- that's my hair."

Best practices for criminals are also helpful for dating. In short, leaving some mystery as to whether you're all in will make you seem more desirable. Consider that we value things that are hard to get, which is why people spend thousands of dollars on rings with sparkly rocks chipped out of African mines when there are very pretty sparkly pebbles that can be picked up all over suburbia.

Psychologist Robert Cialdini explains that the less available something seems, the more desirable we perceive it to be. This doesn't mean it is more valuable, but fear of losing access to it kicks off a motivational state in us: a drive to get it that we don't feel when we hear, "More where that came from! Our supply's basically on the level of 'plague of locusts.'"

The thing is, you can tell somebody you're into them through how you look at them and touch them. Consider where your longing to be immediately "honest" in spoken-word form might be coming from. Holding back information causes psychological tension, as does the suspense when we're left wondering how another person feels. This tension is uncomfortable, so we long to relieve the pressure, like by exploding our feelz all over the person who inspired them. Tension released! Uh, along with the message that we're probably deeply needy and "not all that."

Try an experiment: With the next three guys you date, make a pact with yourself to tough out the discomfort instead of flapping your lips to make it go away. In practical terms: Don't confess. Just be. You'll ultimately have a better chance of finding the "emotional honesty" you're looking for than if you try to rush the process -- like by calling the guy up and blurting out, "Hi...I really love you!" A strangely familiar male voice responds: "I'm sorry, Ma'am. This is the gas company."

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 33-year-old woman with a male partner in his late 30s. We eventually want children, and I've been considering having my eggs frozen. My doctor suggested my boyfriend should consider freezing his sperm. He is a "manly man" type, and his masculinity is a strong part of his identity. How can I keep him from being insulted and angry if I suggest he look into sperm freezing?

--Aspiring Mom

Unfortunately, the men with the healthiest sperm are the 20-somethings who have trouble sustaining adult relationships -- but no problem, because they'll just have their mom call to tell you it's over.

We tend to have a weirdly one-sided view of fertility issues, as if a man's only role in babymaking is the fun part, and never mind whether Daddy's 27 or 70 at the time of conception. Meanwhile, women in their late 30s and their 40s get treated like they have dinosaur eggs. Having a bun in the oven at age 35 or older is referred to as a "geriatric pregnancy" or, less mortifyingly, being of "advanced maternal age." It's associated with increased risk of miscarriage and birth defects, as well as diabetes and high blood pressure in a woman during her pregnancy.

There's little understanding that aging sperm can be a problem, too. Researchers are still squabbling about when men hit "advanced paternal age," but there's general agreement that after age 40, sperm exhibit damage that can make it more difficult for a man to get a woman pregnant and are associated with greater miscarriage rates. There's also an increased risk of having children who develop schizophrenia and autism spectrum disorders. OB-GYN researcher Dr. Nancy A. Phillips and her colleagues suggest that men "bank sperm before their 35th or, at least, their 45th birthday" to limit the risks to the mother, fetus, and child from aging sperm.

In presenting this to your boyfriend, consider that how you frame a story changes the story that gets told. Make this a story not of elderly sperm but of the very manly act of protecting the woman he loves from harm (along with any baby who might enter the picture). Chances are he'll see looking into sperm-freezing as a positive thing: a way he can preserve his he-man-liest sperm -- instead of waiting till his varsity swimmers are more like old dudes floating on water wings in the condo pool.

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.