Whether it's getting your partner to do more housework or making your colleagues back your latest idea, we all end up spending a considerable amount of time trying to persuade or even manipulate others.
So can science offer any clever tricks to get people to do what we want, without resorting to bullying them? It's complicated, but some 30 years of psychological research suggest there might just be a few methods that are worth a try.
Use a person's body against them
Got a date coming up? Maybe you should consider taking them to see a horror movie. "Misattribution of arousal" is a popular theory in social psychology that suggests people sometimes mislabel feelings from their body.
For example, you experience an elevated heart rate when you are anxious, but also when you are excited.
Psychologists have therefore been experimenting on whether it is possible to use this idea to manipulate individuals into thinking they are experiencing particular emotions, such as believing they are attracted when they're actually scared.
In one such study, an "attractive female interviewer" asked male passers-by to complete a questionnaire while standing on a rickety suspension bridge that hung high above a gorge.
She also asked another set of men to complete the questionnaire on a sturdy, low-hanging bridge (not likely to evoke fear). She told them they could call her afterwards if they wanted more details on the study.
Amusingly, significantly more men called the interviewer if they had met her on the fear-inducing bridge.
Similar studies have found that men also rate women as more attractive if they have had an injection of adrenaline (that they were told was vitamins), been startled, doing exercise or listening to a taped story designed to cause shock.
Most of these studies looked at men's reaction to women, but the effect seems to hold true for women too.
It was first thought that this happens because participants experienced arousal from an unclear source, and looked to the situation they were in to provide context.
Later reviews have suggested that, while it may not – in fact – be possible to implant an emotion through suggestion, it is possible to intensify pre-existing feelings in this way.
A compulsion for reciprocity
Somewhat counter-intuitively, if you want to get something from someone – you should give them something yourself.
The "reciprocity norm" describes the way people feel (often strongly) indebted to a person who has bestowed a gift or favour upon them until they repay in kind.
Charities have been using this principle to increase donations for decades: providing an unconditional gift before a donation (even a humble paperclip) can increase the amount given by up to 75 percent, as it unconsciously obliges the individual to give back.
However, one must be careful using this strategy. Providing external incentives (like a gift) when trying to get something, can actually decrease giving in certain situations – particularly with respect to charitable giving.
This is because getting a reward can undermine the intrinsic altruistic motivations for giving (making it more like getting repaid for your charity).
Or, because it takes away another strong motivator for giving: looking generous in the eyes of others (taking a gift could make you look less "pure").
Use clever language
Another way to beguile someone involves picking your words to help you maximise your chances in a very subtle way. For instance, in an argument, your choice of pronouns can surprisingly affect how people react to what you say.
Using statements beginning with "you" ("you should have finished that report") will evoke more antagonism in the recipient as opposed to statements beginning with "I" ("I am stressed because the report is not done").
This is because removing the "you" removes the accusatory element.
Another linguistic trick is to use nouns rather than verbs when discussing an outcome you want to happen.
In one study people were asked "how important is it to you to be a voter in tomorrow's election?" versus "how important is it to you to vote in tomorrow's election?" When people were asked about "being a voter", this primed their self-identity as a person who votes.
The people who were asked about being a "voter" were 11 percent more likely to vote in a state election the next day, compared to those who were asked about "voting".
There are also various other body and language tricks you can employ that have been shown to increase people's liking or trust in you, such as subtly mimicking people's body posture, looking people in the eye more frequently and saying their name more often.
Use rewards and punishments variably
Does your loved one need some "behaviour shaping"? Maybe a bit more hanging up the bathmat, and a bit less using your toothbrush?
We all know that you can increase the likelihood that someone will do something by rewarding it, and decrease it through punishment.
So if you want someone to keep doing something (or to stop doing something), you can simply alter the schedule by which you dole out rewards or punishments to maximise their compliance.
A variable reinforcement schedule like this works by the slightly creepy "will they, won't they" principle – where the uncertainty makes people learn faster and maintain a behaviour longer once the reward or punishment is removed.
In the same way, not knowing how many more plays you need before you win is part of what makes gambling and the lottery so addictive.
Ask for something you don't want
A large body of popular research suggests that if you are trying to get something, you may help your case by also asking for something you don't want.
The "foot-in-the-door method" refers to the fact that, once a person has agreed to a very small request, they are more likely to agree to another, much larger request – significantly more so than if they were only posed with the large request.
It was first suggested this must occur because people use their own behaviour as a cue to their internal attitudes.
Since they were not pressured externally into agreeing, the person unconsciously infers their acquiescence is due to a positive attitude towards the asker or the issue.
The effect seems to hold even when the second request is a completely different type, or when made by a different person.
Given this, it was thought that perhaps the first "yes" changes the individual's own disposition towards saying yes to things in general ("I am clearly such a yes man").
On the flip side, if you ask for something outrageously large that a person would never agree to, you actually raise your chances of agreement to a second smaller request.
This may also be a form of reciprocity effect: the person being asked is compelled to make a compromise, in response to the asker making a concession.
In sum, social psychology may not change your life … but it may just help you get the last biscuit.