I'm a single man in my 30s, and I don't want a relationship right now. I keep meeting women online who say they only want something casual. Then, on the first or second date, it becomes obvious that they want a relationship, not just fun and sex. What's with the bait and switch?

--Annoyed

Nothing like arriving for your reservation at a steak house only to be told, "We're out of a few things tonight -- everything made of cow. But good news! We've still got carrot kebabs, cauliflower schnitzel, and kelp stroganoff!"

Women who bait and switch like this -- revealing their relationshippy intentions between the appetizers and the end of date two -- are reflecting what evolutionary psychologists David Buss and David Schmitt call men's and women's conflicting "sexual strategies." These are best summed up as "happily ever after" for women versus "hookupily ever after" for men.

These differences in sexual strategy trace to differences in "obligatory parental investment." This refers to how a man can bolt after sex -- "Thanks, but I'll pass on doing the dad thing!" -- while a woman can get pregnant and stuck with a kid to drag around and feed.

Accordingly, Buss and Schmitt explain that women typically benefit most from a "long-term sexual strategy," vetting men to see whether they'd commit, meaning stick around to invest in any children that might come out of sex. Men, however, benefit most (that is, leave more descendants carrying their genes) from a "short-term sexual strategy" -- having casual sex with a variety of hot-erellas.

This doesn't mean that men never want to commit or that women never want to hook up. They do this when circumstances make it in their best interest. But because men and women coevolved, they are at least subconsciously aware of each other's intentions and shade the truth to put themselves in the most "marketable" light. So, men often act more interested in commitment than they actually are (in hopes of getting sex) and women often act less interested, in hopes of ensnaring Harry Hookup and turning him into Harry the Husband.

It probably makes sense to err on the side of assuming a woman will want commitment, whether she knows or articulates that or not. Opt for my "cheap, short, and local" advice for first and second dates: Meet for happy hour drinks or coffee for an hour or two, max. You still might get women who said they just want casual fun going gooey on you at the end of date two. At least you won't have shelled out for filet mignon and fine wine only to hear the no-strings-attached sex version of "First 100 callers get a free TV!" ... "Oh, sorry, sir...you're caller 101."

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 girlfriends are all writing out their visions for a partner, as if they've met him already ("Thank you, universe, for bringing me this man..."). They claim they've gotten boyfriends because of it. Is this just New Age crap, or is there something to writing down what you want?

--Boyfriend-Seeking

This apparently is a thing, women writing a letter about the man of their dreams and then feeling like they ordered online from the universe: "My man's on his way. Just waiting for the tracking number!"

Once they get a boyfriend, the belief that their letter writing made it happen comes out of a common cognitive bias -- a hiccup in rational thinking -- called the "illusion of control." This term, coined by psychologist Ellen Langer, describes people's tendency to believe they have control over outcomes that they obviously do not. An example of this is gamblers blowing on dice -- and not because the dice have complained bitterly that they are freezing to death and left their tiny square cardigans at home.

Ironically, the fact that it's irrational to do this doesn't mean it's unhelpful. Research by psychologists Michael I. Norton and Francesca Gino finds that a ritual, a "symbolic activity" a person performs in hopes of making something happen, tends to increase their "feelings of control" over situations in which outcomes are uncertain. This, in turn, decreases the stress they feel.

In other words, it's possible that the ceremonial act of writing a "Dear Santa" letter to the universe could make a woman more appealing to men by calming her down and getting her to act less crazy and desperate. It's like putting in an order at a restaurant. You have faith your dinner is coming; you don't stalk the waiter on Instagram and text him 30 times, alternating pictures of your boobs with plaintive questions and abuse: "Is the chef okay? ... Are you on a smoke break? ... I bet you gave my steak to a prettier girl. ... You're a terrible waiter. ... I hate you."

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.

About six weeks ago, I started dating the nicest guy. I have some intimacy issues (basically, fear of abandonment), and having somebody be nice to me is new and uncomfortable. I freaked out one night and had sex with somebody else. I know this guy I'm dating isn't sleeping with other women, but we haven't had the official talk. I don't plan on doing this again, but I really want to confess. The guilt is terrible.

--Disgusted With Myself

The only man in your life with whom you should be discussing your recent sexual history is Dr. Maury Finkelbaum, your 7,000-year-old gynecologist.

You and Neighbordude might be all kinds of fond of each other, but you have no agreement for sexual exclusivity, and you can't violate a treaty that doesn't actually exist. Still, assuming that he isn't getting it on with anyone else, it's natural that you'd feel guilty about an apparent asymmetry in sexual grazing.

Human psychology evolved to have a sort of inner accounting staff monitoring the fairness level of our behavior -- calculating whether we're giving as much as we're getting. However, unlike everybody's grandma, evolution doesn't care whether we're nice people. It just wants us to survive so we can pass on our genes. Accordingly, this fairness monitoring system safeguards our physical survival through safeguarding our social survival. (In ancestral times, slackers or freeloaders booted from the ancestral band markedly increased their chances of becoming some sharp-fanged thing's Sunday brunch entree.)

Even today, when we perceive that we're getting more than our fair share of something -- whether it's cake or sex with hot strangers -- our behavioral accounts payable team pings us in the form of feelbad: the noxious, gut-churning feeling of guilt (and/or its poisonous BFF, shame).

Research by evolutionary psychologist Daniel Sznycer and his colleagues deems guilt a "recalibrational emotion." Translated from the Professorese, this means that our wanting to stop the feelbad from guilt motivates us to even the balance between ourselves and somebody we've shorted in some way.

The thing is, emotion, which rises up automatically, with no effort from us, needs to be fact-checked by reason. Unfortunately, reason has to be dragged out of bed and forced to work. And that's what you need to do with yours. Again, remember that you and this guy had no exclusivity agreement that would have barred you from venturing into other men's beds, back seats, or sex dungeons.

Also, let's get real on why you're longing to tell. It isn't to make the guy feel better but to make yourself feel better -- to rid yourself of the psychological tension that comes from holding back information. (It's basically the emotional version of a really bad need to pee.)

Next, consider the view from psychiatrist and evolutionary researcher Randolph Nesse that painful emotions are important motivational tools -- just like physical pain, when you, say, lean back at a party, all apex of cool, and rest your palm on a hot stove. Just as the searing pain gets you to lift your hand pronto, you can use your guilt-induced discomfort in a positive way: as reinforcement against your stepping out on the guy once you two do have a relationship.

Other helpful insight comes from research on "attachment." The "attachment behavioral system," explain social scientists Mario Mikulencer and Philip Shaver, motivates human beings, from infancy on, "to seek proximity to significant others (attachment figures) in times of need." A person's "attachment style" indicates the degree to which a person "worries that a partner will not be responsive in times of need" (including the worry that one's partner will flee the relationship entirely).

However, Mikulencer and Shaver note that "a growing body of research shows that attachment style can change, subtly or dramatically." One way to change it is through asking your partner to be very physically and emotionally expressive with you in loving, cuddly-wuddly ways. Research by psychologist Brooke C. Feeney finds that the more an insecurely attached person sees their partner is there for them -- like with touch that "conveys acceptance, warmth, and intimacy" -- the more independent (that is, the less clingoramous) they can be.

Finally, there's something you can do to help yourself feel more secure, per Mikulencer and Shaver's research: Turn on the TV in your head and run helpful programming -- mental video of warm, fuzzy "attachment figures." The researchers explain that "thoughts of an available and supportive attachment figure" lead people with a lot of attachment insecurities "to behave more like secure people." Or, putting this another way, your response to a man being really loving to you would be to give love in return -- as opposed to giving excuses like "I was so freaked out by how nice you were to me that I tripped and fell on somebody else's penis."

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 in a weird place in my life: My work situation's up in the air, and there's a lot of uncertainty in my romantic life and my living situation. Friends are telling me to be patient and live in the moment, but I'm finding all of this not knowing extremely upsetting. Is there anything I can do to feel less anxious?

--Distressed

When everything seems uncertain, it's easy to go really dark: "Please forward my mail to the refrigerator box in the underpass where I'll soon be living with my fiance, the cat."

Decision researchers have consistently found that we humans have a strong "ambiguity aversion" or "uncertainty aversion." We get seriously unsettled by the big foggy monster of the unknown: not knowing what's going to happen or not having enough information or expertise to reasonably predict it.

As for what's going on under the hood, brain imaging research by neuroeconomist Ming Hsu and his colleagues found that the amygdala -- an area of the brain tasked with spotting threats and mobilizing our response to them -- was more activated in response to "ambiguity" (that is, when research participants asked to make decisions had information withheld from them).

This freakout by our brain's Department of Homeland Security would have been a good fit in the ancestral times in which it evolved. Back then, an uncertain world was an especially life-threatening world, because there were no antibiotics, fire departments, or rubber-soled shoes. These days, however, we're living in a world vastly safer than the one our psychology is adapted for. This one's got countless cushions which make disasters go down less, well...disastrously.

To tamp down the queasiness of uncertainty, verbalize your fears. Research by neuroscientist Matthew Lieberman suggests this depowers the amygdala by putting the prefrontal cortex, the brain's reasoning center, to work. Tell the story of your worst fear in each of your uncertain situations: Your boss not only fires you but chases you out of the building with a broom. Then, carrying a box of your stuff, you come home to your roommate in bed with your boyfriend. Then you go out for a beer, only to return to a smoking pile of ash where your apartment used to be.

Obviously, you'd prefer that none of this happen. However, you aren't unemployable or unloveable, and you have friends with couches, and there's Airbnb. (Worst-case scenario -- and of course, I'm not actually advising this -- you go to the hospital and tell them George Washington is talking to you through your eyeglasses and get three hots and a cot for 72 hours.)

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 in my late 40s. I've noticed many of my friends reconnecting with and marrying people they knew years ago -- sometimes friends, sometimes exes. Is everybody just desperate, or is dating all about timing?

--Wondering

In your early 20s, you know what's vitally important in a partner: that he doesn't have "weird nostrils" or wear a belt buckle with his own name on it.

Then you do some living and maybe get shredded by a relationship or two, and your preferences change. In short, context matters. Context is simply your personal circumstances, and it includes factors like your own mate value, the man-woman ratio where you are (or the availability of same-sex partners if you're gay), and whether you're in a hurry to have a baby before your ovaries retire to a cabin.

It turns out that when looking for partners, we have a budget. It works like it does at the supermarket. You can buy the finest steak and lobster and then starve for the rest of the month, or you can shop more in the Top Ramen and lunchmeat arena and keep yourself consistently fed.

Evolutionary psychologist Norman Li applied this budgetary approach in researching partner preferences. Prior research had poor methodology, simply asking, "Hey, what do you want in a partner?" Well, if somebody asks you that -- sky's the limit! -- what's your answer? "Um, is Chris Hemsworth available? How 'bout Liam?" But when you're constrained, you have to make tradeoffs. You have to "buy" the important qualities first -- "necessities" versus "luxuries," as Li put it. When research participants were most constrained, intelligence and kindness were major priorities for both sexes. When budgets expanded, there was more "spending" in other areas, like creativity.

This might explain why people in their 40s suddenly see something in people they tossed aside years ago or maybe just never thought of as partner material. Basically, at a certain point, many people give up on finding the exact right person and look for a right enough person. For some former sticklers, there comes a point when they're all, "I'm game!" if a guy's address isn't WHX134 (his car's license plate) and he doesn't have multiple wives (two or three of whom he's still married to).

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.

A friend agreed to dogsit while I flew up to visit my ailing dad. She bailed at 7 p.m. the night before I flew out, saying she needed three days to pack for a vacation. She never even apologized. I don't want to be friends anymore. She said, "You're throwing a friend away over not watching your dog." But it's not that. It's that she broke her word and left me in a huge bind. Still, I feel bad about cutting her out of my life, as we've been friends a long time. Thoughts?

--Disgusted

This is like that game Trust, where you let yourself fall backward in the belief that somebody will be there to catch you. In this case, your catcher ran off last minute for a mani-pedi, and you woke up in the ER getting the crack in your head stapled shut by four surgical residents.

At least your anger hasn't deserted you. Maybe that sounds odd, given that anger gets a bad rap as a "destructive" emotion. But anger actually has an important function. It's a "recalibrational emotion," one of a few emotions -- along with shame and embarrassment -- that evolutionary scientist Aaron Sell explains evolved to regulate our own behavior as well as someone else's.

Sell writes that anger arises in a person in response to their perception that another person "does not value their interests highly enough." This motivates the angry person to push for better treatment. There are two tactics for this: inflicting costs (sometimes simply through the scary ugliness of aggression) or withdrawing benefits.

The function of these two tactics, Sell explains, is to show the other person (the slacking offender) that they will be worse off if they keep neglecting the angry person's interests. Interestingly, in research across six cultures -- including Shuar hunter-horticulturalists in the Amazon -- Sell and his colleagues found that people were "less angry when harmed for a large benefit compared to a small benefit."

Accordingly, chances are you'd be less angry and less motivated to retire this woman as a friend if she'd bailed after being hit by some big emergency. Instead, it seems she just wanted to spend three days packing for her trip unimpeded by the slightest bit of doggie care. That desire in and of itself isn't wrong, but being friends with someone (and getting the benefits) can involve some inconveniences from time to time -- putting yourself out to make things better for a person you care about.

What's more, this woman never apologized. So, your anger -- your imposing a cost on her -- did not motivate her to feel remorse or show you that your needs and feelings mean something to her. Yes, it's good to keep friends -- if they actually act like friends. Otherwise, you should probably treat them like a broken vacuum cleaner. Correct me if I'm wrong, but you probably wouldn't keep it "for old time's sake!" after it starts to smoke, blow big dust clouds, and scream like 20 goats being slaughtered in your living room.

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 should you do when a man you've been dating stops texting or otherwise responding? We had an amazing time when we were last together. I can't believe he just isn't interested. Should I call? Drop by? What do you suggest?
--Hurt

As a woman, there's sometimes good reason for you to chase a man, like that he's good-looking and funny and has also stolen your wallet.

A man who's interested in you will not need chasing. In fact, if he's really into you, he will chase you like a dog chases a squirrel...a squirrel wearing a tiny jumpsuit made entirely out of bacon. Unfortunately, human psychology is particularly bad at helping us detach from lost causes, motivating us to lead with our ego and emotion rather than reason. For example, we're prone to keep putting time, energy, and and/or money into something based on what we've already invested -- what we've already "sunk" into it. This is called the sunk cost fallacy, and it's irrational behavior because our initial outlay is gone. The rational approach is to base any further investment on how likely the thing is to pay off in the future.

Cut your losses. Come up with an ego-soothing explanation for his disappearance -- like that he was kidnapped from the mall parking lot and never seen again. Crazy as that advice might sound, research on memory by psychologist Elizabeth Loftus actually finds we are quick to turn our malarkey, especially our repeated malarkey, into our reality, i.e., what we believe. Also, quite frankly, there's a good chance he actually was kidnapped -- though probably just by some other woman's butt cleavage.

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.