Why are some people more motivated (积极的) to handle difficult things? And is there a way to make doing difficult things easy? To answer this question, we need to look at this: dopamine (多巴胺). Dopamine is often considered a pleasure molecule (分子). But that’s not quite what it does. Dopamine is what makes us desire things. And it’s that desire that gives us the motivation to get up and do things.

In fact, your brain considers something more important than others mainly depending on how much dopamine it’s expecting to get. If an activity releases too little dopamine, you won’t have much motivation to do it. But if an activity releases a lot of dopamine, you’ll be motivated to repeat it, over and over. So which behavior releases dopamine? Any activity where you expect there’s a possible reward releases it.

And in today’s digital society, we are flooding our brains with unnaturally high amounts of dopamine on a daily basis, even if we don’t know it. Some examples of high dopamine behavior include: visiting social media websites, playing video games, etc.

And you might think, “Oh so what? It’s not like it’s harming me in any way.” But you’d be wrong. Our bodies have a biological system called homeostasis (体内动态平衡). Whenever an imbalance occurs, our body adapts to it. Basically your brain gets used to having high levels of dopamine and those levels become your new normal. Thus you develop a dopamine tolerance. This can be a huge problem because the things that don’t give you as much dopamine don’t interest you any longer. That’s why people tend to prefer playing video games or surfing the Internet, compared to studying or working on their business.

But it is possible to make doing difficult things feel easier. Separate yourself from the unnaturally high amounts of dopamine, or at least expose yourself to it far less frequently. Only then will normal, everyday, low dopamine activities become exciting again and you’ll be able to do them for longer. That’s why you might want to limit your phone and computer usage, along with other high dopamine-releasing behavior.

We are all dopamine addicts (入迷的人) to a certain extent. And that’s a good thing because dopamine motivates us to achieve our goals and improve ourselves. But it’s up to you to decide where you’re going to get your dopamine. Are you going to get it from things that don’t benefit you? Or are you going to get it from working on your long-term goals? The choice is yours.

Dieting is often doomed to failure．The problem is, we don't follow the rules we learn．No carbs after 6pm？No problem-until we're out for dinner, on our second glass of wine and reaching for the bread basket．Everyone has a flash point that makes it hard to say no, but ultimately, resisting temptation is the key to successful weight loss．

Now research from leading psychologists has identified the parts of the brain involved in resisting temptation, and how we can use them to stop reaching for chocolate cake．Leading the charge is Professor Walter Mischel, the psychologist who developed the ‘marshmallow test', which demonstrated that if children were able to delay gratification（满足感）, they would be more successful in later life．Mischel’s research has shown that to resist temptation, we have to shift activity away from the ‘hot’ parts of our brain to the ‘cool’ parts．The mind brain has two systems：one is cool, slow and deliberate, and allows for self-control, goal-setting and willpower-the ‘no’ system, if you like．The other is hot, emotional and instinctual, and present from birth-the ‘go’ system．

So when you see a chocolate cake, the ‘hot’ part of your brain reacts to thoughts of the delicious taste, and the sugar rush that you have learnt a slice will give you．Instead of giving in, what you need to do is to activate the ‘cool’ part of your brain by thinking about your goals and practicing far-sightedness．Imagine the sense of satisfaction you'd get, from fitting into your favorite dress in a couple of weeks’ time, say, or from losing your unsightly tummy bulge before you go sunbathing this summer．It's a simple strategy, but experiments have shown it is highly effective．

Perception is also important．Feasting your eyes on desirable food activates the hot system in the brain, which explains what we know instinctively：putting biscuits out of sight in a cupboard will mean you eat fewer of them．"The problem with diets is they are also full of pictures of delicious diet food； and all of this is just activating the hot system, "Mischel says．

Stress is another key issue．It has been shown to switch on the hot part of the brain and cause us to overeat．The first thing to do is to be aware of how stress changes your behavior．Then develop an action plan to deal with it．This might involve taking healthy snacks to work or finding ways to cope better with your time and emotions．

Brain scans have also shown that memory plays a significant role in overeating．If you habitually eat chocolate, for instance, then every time you see it, you remember the high．So the research is clear：if you want to be slim, fit and healthy, it's time to take control of your mind．

It's common knowledge that the woman in Leonardo da Vinci's most famous painting seems to look back at observers, following them with her eyes no matter where they stand in the room. But this common knowledge turns out wrong.

A new study finds that the woman in the painting is actually looking out at an angle that’s 15. 4 degrees off to the observer's right-well outside of the range that people normally believe when they think someone is looking right at them. In other words, said the study author, Horstmann, "She’s not looking at you. " This is somewhat ironic, because the entire phenomenon of a person's gaze( 凝视) in a photograph or painting seeming to follow the viewer is called the "Mona Lisa effect". That effect is absolutely real, Horstmann said. If a person is illustrated or photographed looking straight ahead, even people viewing the portrait from an angle will feel they are being looked at. As long as the angle of the person's gaze is no more than about 5 degrees off to either side, the Mona Lisa effect occurs.

Horstmann and his co-author were studying this effect for its application in the creation of artificial-intelligence avatars (虚拟头像) when Horstmann took a long look at the ”Mona Lisa" and realized she wasn't looking at him. To make sure it wasn't just him, the researchers asked 24 people to view images of the “ Mona Lisa" on a computer screen They set a ruler between the viewer and the screen and asked the participants to note which number on the ruler intersected Mona Lisa’s gaze. To calculate the angle of Mona Lisa’s gaze as she looked at the viewer, they moved the ruler farther from or closer to the screen during the study. Consistently, the researchers found, participants judged that?the woman in the “Mona Lisa” portrait was not looking straight at them, but slightly off to their right.

So why do people repeat the belief that her eyes seem to follow the viewer? Horstmann isn’t sure. It’s possible, he said, that people have the desire to be looked at, so they think the woman is looking straight at them. Or maybe the people who first coined the term “Mona Lisa effect” just thought it was a cool name..

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