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Resist!
Resist!
Every day we battle to defeat temptation and make the best long-term choices. Helen Phillips learns the art of self-control
●
WALTER MISCHEL can predict the future using a bag of marshmallows. In experiments he started in the 1960s at Stanford University, he discovered that if 4-year-olds could resist eating a marshmallow while he briefly left the room – for the promise of two marshmallows on his return – they were more likely to have higher university entrance exam scores later on, better paid jobs, successful marriages and better health. In this, the longest-running study of self-control, Mischel, a psychologist now at Columbia University in New York, has tested the willpower of more than 650 pre-school children, and followed many of them as they have grown up and had children of their own. His finding, that some people have stronger willpower than others, will come as no surprise to those struggling to give up
Animal urges Animals are generally thought to act largely on impulse or instinct, but experiments designed to test the patience of rats, pigeons, chimps and monkeys have shown that they can all exert a level of self-control. Pigeons, for example, can resist an immediate small treat to wait for a bigger food reward, but only for a few seconds. Monkeys will wait a minute or two at most to get a better reward, while apes will give up less-preferred food easily for a favourite, waiting 20 minutes or longer. However, chimps show some real qualitative differences,
40 | NewScientist | 13 September 2008
according to Michael Beran, of Georgia State University in Atlanta. They deliberately distract themselves and genuinely seem to anticipate a better future, he says. Surprisingly, humans are actually less patient when waiting for a food reward than chimps, suggests a recent study by Alexandra Rosati from Duke University in Durham, North Carolina, and colleagues. They also showed that people will readily wait longer for money than food, suggesting that selfcontrol varies according to a species’ most pressing priorities.
smoking or stick to a diet. More intriguingly, though, he has found that how well we control our impulses is determined early in life. Not only that, self-control plays a key role in our lifelong health and happiness. The good news is that if you’re not naturally blessed with self-control, there are some ways to improve it. As you might expect, the difficulty in resisting a treat or to getting on with a chore depends largely on how it compares with what else is on offer. In Mischel’s tests, for example, the ability of children to wait for a better treat depended on the desirability of the treat, how long he asked them to wait, and whether they were looking at or thinking about the reward while waiting. Yet even controlling for all these factors, some children were simply good at controlling their impulses. So why are some people better able to control themselves then others? Socio-economic factors may play a role. Further studies with the Stanford volunteers have shown that better off and more intelligent children, particularly those with a high verbal IQ, are slightly less impulsive on average. There is more to it than intelligence and upbringing, though, says Ozlem Ayduk at the University of California, Berkeley. Ayduk suggests that smarter kids can handle the delay better by using deliberate tricks to keep the immediate reward from their mind and avoid temptation. However, “even when the studies control for intelligence, some kids are better at deploying their attention”, she says. Ayduk is now looking at the offspring of the original Stanford volunteers to try to discover if the skill is inherited, though there are no early signs www.newscientist.com
GRAHAM RAWLE
of a strong link. She has also teamed up with a group of neuroscientists to see if they can find any differences between the brains of the impulsive and restrained members in the original volunteers. This will not be easy. Functional brain imaging studies have revealed that a complex circuit of brain regions are involved in keeping us on track. The exact areas used vary depending on the task – whether people are controlling an impulse to do something, trying to stick to a task, or suppressing emotions, for example. Nevertheless, much of the activity seems to be centred on the frontal lobes of the brain, particularly on the right side, says neuroscientist Hugh Garavan from Trinity College in Dublin, Ireland. When these right frontal lobe regions are temporarily, and harmlessly, disrupted by a non-invasive technique called transcranial magnetic stimulation, Garavan found that people become worse at computer tasks testing impulse control. For example, knocking out these areas made people perform worse than they normally would when asked to press a key on seeing an image, but to resist pressing www.newscientist.com
“Self-control is key to our lifelong
health and happiness. The good news is you can improve it“ the key if a specific picture appeared. These brain regions overlap with the areas that handle our working memory – where we hold information from moment to moment. Studies show that taxing our working memory also makes self-control harder, suggesting that the two processes are somehow linked. While it’s hard to define precisely what makes a person impulsive or restrained by looking at their brain, there are changes with age that give some clues. The frontal lobes are the last parts of the brain to mature, and are still growing and changing well into our twenties. This could explain why teens tend to be less well disciplined and more prone to thrill-seeking than other age groups. Teenagers experience pleasure and reward in the same way as an adult,
says Garavan, but their ability to control their basic urges is different. The elderly too have a reputation for being uninhibited, though it’s more a tendency to express uncensored opinions then a return to the recklessness of youth. Brain imaging studies show that as we age, the impulsecontrol network recruits more areas of the brain for the task, suggesting that it becomes less efficient. Perhaps restraint takes more effort as we get older. Gender may also play a part. Males, in general, seem to be less able to control their impulses than females, with the difference being evident in 4-year-olds. This could perhaps be due to social expectations which may make young girls more obedient and eager to please than boys. However, males are more likely to suffer from impulse control 13 September 2008 | NewScientist | 41
GRAHAM RAWLE
problems such as rage, attention-deficit hyperactivity disorder (ADHD), drug use and antisocial personality disorders, suggesting they may be naturally less able to hold back. The differences could be partly down to the effects of sex hormones on the brain, Garavan suggests. A woman’s impulse control can certainly change with her menstrual cycle, he has shown. While there may well be differences in the brain that predispose us to good or poor self-control, some researchers believe exercising willpower has not just a neurological basis, but a physiological one too. Suzanne Segerstrom, a psychologist at the University of Kentucky in Lexington, says that we undergo subtle physiological changes as we use our willpower. In experiments she monitored “heart rate variability” (HRV), tiny variations in heart rate from beat to beat, as people ate carrots and resisted cookies. HRV is known to vary with emotional and mental state as we adapt to changing stresses. Segerstrom found that people who were most able to resist temptation had a temporary increase in HRV as they used their willpower, followed by a temporary drop (Psychological Science, vol 18, p275). She believes that this subtle change in heart rate is an indicator of a physiological “pause and plan” response as we try to ignore what we want and focus on what we know is good for us. Since people with a naturally high HRV were more able to resist temptation than others, this is further evidence that some people have an in-built advantage when it
Get a grip on yourself CHOOSE YOUR BATTLES Willpower is a limited resource, so use it wisely. Making big decisions, resisting temptation or controlling your emotions can all deplete willpower. MAKE A PLAN Writing a clear plan about your intentions to do something, including full details of how, when and where, makes it much more likely you’ll get the job done. BOOST YOUR ENERGY Exercising willpower depletes energy levels, in the form of blood glucose, just like physical exercise. No wonder those chocolate biscuits are so tempting while working. PRACTISE Like strengthening a muscle, you can strengthen your willpower by training.
42 | NewScientist | 13 September 2008
Sticking to a plan to go to the gym or exercising other forms of self-control can, over time, boost your resolve in other domains. GET INTO THE HABIT Set up an external trigger for what you want to do, for example going to the gym at 5pm every Tuesday. Removing the conscious decision and making a mental connection will make it easier to get started, and will turn it into a habit. BE SPECIFIC If your goal is specific, rather than vague or general, you are more likely to succeed. THINK POSITIVE Focusing on a positive goal can sometimes be more successful than avoiding a negative one. Aim to win, rather than fear losing.
comes to resisting temptation. But everyone’s inner resolve is occasionally stretched to the limit. Roy Baumeister, a social psychologist at Florida State University in Tallahassee, believes this is because willpower is more than just a metaphor. Self-control requires inner strength and effort, he says, and that means you can use it up. He and Mark Muraven, now at the State University of New York, Albany, demonstrated this in 1998 by asking volunteers to resist eating either radishes or freshly baked cookies. After about 5 minutes they were given a test consisting of impossible puzzles, with each group being monitored to see how long they persisted at trying to solve them. People who had resisted cookies, which everyone found harder then resisting radishes, had less sticking power at the puzzles (Journal of Personality and Social Psychology, vol 74, p 1252). Baumeister believes this is because we use up a store of willpower resources every time we make the effort to hold back or do something we don’t want to do. Exercising willpower is like exercising a muscle, he says, and it takes time for the resources used to be www.newscientist.com
Just say “no” Anti-drug messages that tell people to “just say no” may be missing an important point, according to Hugh Garavan of Trinity College in Dublin, Ireland. Some people may simply not be able to. Garavan has recently discovered that in cocaine addicts a network of frontal lobe regions involved in impulse control seem less active than normal. The ability to hold back all kinds of impulses was impaired, not just the desire to take drugs. When addicts took cocaine, though, it raised their brain activity and performance to normal levels. Until now, addiction research has focused
replenished. Making difficult decisions and coping with stress may deplete the same resources, also sapping willpower. He has since suggested that blood glucose levels are the key to keeping our willpower strong. By giving people a sugary lemonade drink before they completed a willpower exercise, he found that subsequent selfcontrol was not depleted in the same way as in those who had no drink or an artificially sweetened lemonade (Psychological Science, vol 19, p 255). “Conscious, effortful control uses energy,” he concludes. This could explain why all-encompassing health drives so often fail. Kicking the cigarettes may take all your available willpower, leaving little in the tank to fuel the new exercise regime and healthyeating plan. Given all this evidence that our ability to control ourselves is determined by biology, there may seem little point trying to change our ways. There are a few tricks, though, that
on reward and pleasure circuits, Garavan points out. What’s clear is that not only is the desire altered, but the impulse control too. What’s not clear is whether the damage is done by drugs, or whether those with impaired control are more likely to use them. Either way, there is evidence that even drugs that may be relatively benign in adults could be toxic to developing brain tissue. Since the impulse control networks continue to mature throughout adolescence, there’s now a physical reason to be concerned that drug exposure during the teens could increase the risk of lifelong addiction.
can help you improve it (see “Get a grip on yourself”, opposite) Brain imaging experiments by Garavan and colleagues have shown that practise can boost self-control in tests. This training seems to have the opposite effect to the ageing process – the areas of the brain involved seem to become more efficient with use, and less of the brain is called into action. However, Torkel Klingberg of the Karolinska Institute in Stockholm, Sweden, who has had some success with training working memory, has not found any evidence that self-control training effects last for the long term or outside the trained setting, at least not in young children. “Despite improvements on the trained task we did not find any transfer after training in 4 to 5-year-old children,” he says. Nevertheless, Baumeister has found that working on your self-control in one area of life can have a positive impact elsewhere. When he asked people to concentrate on correcting their posture every time they thought of it for a period of two weeks, he found that persistence in puzzle solving and other tests of self-control improved. Similar effects were seen when he asked people to adhere to a programme of exercise, suggesting that it doesn’t matter what routine you stick to, just sticking to something can improve your overall self-control. Clearly, though, improving your willpower the Baumeister way requires a certain amount to self-control to stick to the programme in the first place. However, according to psychologist Peter Gollwitzer of New York University and the University of Konstanz in Germany, there is another way to stay on track. Gollwitzer has come up with a method that will help even the worst procrastinator
to achieve a higher level of self-control. He stumbled across the idea while studying people’s states of mind during different stages of motivation and action. As part of an experiment, he asked some participants to write out exactly how they would complete a task, giving as much detail as possible about when and where they planned to do it. In subsequent studies he found that people who go through the trouble of making “when-where-and-how” plans were about three times more likely to actually act on their goals. He has since studied the effects of planning on all kinds of intentions and found that it works in almost every domain – from initiating actions and activities where there is an initial reluctance to get started, to altering emotional responses, controlling violence and overcoming stereotypes and phobias (Psicothema, vol 19, p 280). His methods have even improved impulse control in children with ADHD, and he plans to try them more extensively on drug addicts and people with other impulse control problems. According to Gollwitzer, planning works because it takes away some of the conscious mental effort. Even something as simple as saying you will go to the gym at 5pm on a specific day is a more successful strategy than intending to exercise once a week. Planning can turn a difficult conscious decision into an unconscious habit, which makes the whole process faster and more efficient without depleting energy levels. So it seems that, at last, the ultimate healthy, happy and successful lifestyle is in reach. All you have to do is make a watertight plan, keep your blood sugar up and then, as the saying goes, just do it. ●
www.newscientist.com/channel/being-human www.newscientist.com
13 September 2008 | NewScientist | 43
Every day we battle to defeat temptation and make the best long-term choices. Helen Phillips learns the art of self-control
●
WALTER MISCHEL can predict the future using a bag of marshmallows. In experiments he started in the 1960s at Stanford University, he discovered that if 4-year-olds could resist eating a marshmallow while he briefly left the room – for the promise of two marshmallows on his return – they were more likely to have higher university entrance exam scores later on, better paid jobs, successful marriages and better health. In this, the longest-running study of self-control, Mischel, a psychologist now at Columbia University in New York, has tested the willpower of more than 650 pre-school children, and followed many of them as they have grown up and had children of their own. His finding, that some people have stronger willpower than others, will come as no surprise to those struggling to give up
Animal urges Animals are generally thought to act largely on impulse or instinct, but experiments designed to test the patience of rats, pigeons, chimps and monkeys have shown that they can all exert a level of self-control. Pigeons, for example, can resist an immediate small treat to wait for a bigger food reward, but only for a few seconds. Monkeys will wait a minute or two at most to get a better reward, while apes will give up less-preferred food easily for a favourite, waiting 20 minutes or longer. However, chimps show some real qualitative differences,
40 | NewScientist | 13 September 2008
according to Michael Beran, of Georgia State University in Atlanta. They deliberately distract themselves and genuinely seem to anticipate a better future, he says. Surprisingly, humans are actually less patient when waiting for a food reward than chimps, suggests a recent study by Alexandra Rosati from Duke University in Durham, North Carolina, and colleagues. They also showed that people will readily wait longer for money than food, suggesting that selfcontrol varies according to a species’ most pressing priorities.
smoking or stick to a diet. More intriguingly, though, he has found that how well we control our impulses is determined early in life. Not only that, self-control plays a key role in our lifelong health and happiness. The good news is that if you’re not naturally blessed with self-control, there are some ways to improve it. As you might expect, the difficulty in resisting a treat or to getting on with a chore depends largely on how it compares with what else is on offer. In Mischel’s tests, for example, the ability of children to wait for a better treat depended on the desirability of the treat, how long he asked them to wait, and whether they were looking at or thinking about the reward while waiting. Yet even controlling for all these factors, some children were simply good at controlling their impulses. So why are some people better able to control themselves then others? Socio-economic factors may play a role. Further studies with the Stanford volunteers have shown that better off and more intelligent children, particularly those with a high verbal IQ, are slightly less impulsive on average. There is more to it than intelligence and upbringing, though, says Ozlem Ayduk at the University of California, Berkeley. Ayduk suggests that smarter kids can handle the delay better by using deliberate tricks to keep the immediate reward from their mind and avoid temptation. However, “even when the studies control for intelligence, some kids are better at deploying their attention”, she says. Ayduk is now looking at the offspring of the original Stanford volunteers to try to discover if the skill is inherited, though there are no early signs www.newscientist.com
GRAHAM RAWLE
of a strong link. She has also teamed up with a group of neuroscientists to see if they can find any differences between the brains of the impulsive and restrained members in the original volunteers. This will not be easy. Functional brain imaging studies have revealed that a complex circuit of brain regions are involved in keeping us on track. The exact areas used vary depending on the task – whether people are controlling an impulse to do something, trying to stick to a task, or suppressing emotions, for example. Nevertheless, much of the activity seems to be centred on the frontal lobes of the brain, particularly on the right side, says neuroscientist Hugh Garavan from Trinity College in Dublin, Ireland. When these right frontal lobe regions are temporarily, and harmlessly, disrupted by a non-invasive technique called transcranial magnetic stimulation, Garavan found that people become worse at computer tasks testing impulse control. For example, knocking out these areas made people perform worse than they normally would when asked to press a key on seeing an image, but to resist pressing www.newscientist.com
“Self-control is key to our lifelong
health and happiness. The good news is you can improve it“ the key if a specific picture appeared. These brain regions overlap with the areas that handle our working memory – where we hold information from moment to moment. Studies show that taxing our working memory also makes self-control harder, suggesting that the two processes are somehow linked. While it’s hard to define precisely what makes a person impulsive or restrained by looking at their brain, there are changes with age that give some clues. The frontal lobes are the last parts of the brain to mature, and are still growing and changing well into our twenties. This could explain why teens tend to be less well disciplined and more prone to thrill-seeking than other age groups. Teenagers experience pleasure and reward in the same way as an adult,
says Garavan, but their ability to control their basic urges is different. The elderly too have a reputation for being uninhibited, though it’s more a tendency to express uncensored opinions then a return to the recklessness of youth. Brain imaging studies show that as we age, the impulsecontrol network recruits more areas of the brain for the task, suggesting that it becomes less efficient. Perhaps restraint takes more effort as we get older. Gender may also play a part. Males, in general, seem to be less able to control their impulses than females, with the difference being evident in 4-year-olds. This could perhaps be due to social expectations which may make young girls more obedient and eager to please than boys. However, males are more likely to suffer from impulse control 13 September 2008 | NewScientist | 41
GRAHAM RAWLE
problems such as rage, attention-deficit hyperactivity disorder (ADHD), drug use and antisocial personality disorders, suggesting they may be naturally less able to hold back. The differences could be partly down to the effects of sex hormones on the brain, Garavan suggests. A woman’s impulse control can certainly change with her menstrual cycle, he has shown. While there may well be differences in the brain that predispose us to good or poor self-control, some researchers believe exercising willpower has not just a neurological basis, but a physiological one too. Suzanne Segerstrom, a psychologist at the University of Kentucky in Lexington, says that we undergo subtle physiological changes as we use our willpower. In experiments she monitored “heart rate variability” (HRV), tiny variations in heart rate from beat to beat, as people ate carrots and resisted cookies. HRV is known to vary with emotional and mental state as we adapt to changing stresses. Segerstrom found that people who were most able to resist temptation had a temporary increase in HRV as they used their willpower, followed by a temporary drop (Psychological Science, vol 18, p275). She believes that this subtle change in heart rate is an indicator of a physiological “pause and plan” response as we try to ignore what we want and focus on what we know is good for us. Since people with a naturally high HRV were more able to resist temptation than others, this is further evidence that some people have an in-built advantage when it
Get a grip on yourself CHOOSE YOUR BATTLES Willpower is a limited resource, so use it wisely. Making big decisions, resisting temptation or controlling your emotions can all deplete willpower. MAKE A PLAN Writing a clear plan about your intentions to do something, including full details of how, when and where, makes it much more likely you’ll get the job done. BOOST YOUR ENERGY Exercising willpower depletes energy levels, in the form of blood glucose, just like physical exercise. No wonder those chocolate biscuits are so tempting while working. PRACTISE Like strengthening a muscle, you can strengthen your willpower by training.
42 | NewScientist | 13 September 2008
Sticking to a plan to go to the gym or exercising other forms of self-control can, over time, boost your resolve in other domains. GET INTO THE HABIT Set up an external trigger for what you want to do, for example going to the gym at 5pm every Tuesday. Removing the conscious decision and making a mental connection will make it easier to get started, and will turn it into a habit. BE SPECIFIC If your goal is specific, rather than vague or general, you are more likely to succeed. THINK POSITIVE Focusing on a positive goal can sometimes be more successful than avoiding a negative one. Aim to win, rather than fear losing.
comes to resisting temptation. But everyone’s inner resolve is occasionally stretched to the limit. Roy Baumeister, a social psychologist at Florida State University in Tallahassee, believes this is because willpower is more than just a metaphor. Self-control requires inner strength and effort, he says, and that means you can use it up. He and Mark Muraven, now at the State University of New York, Albany, demonstrated this in 1998 by asking volunteers to resist eating either radishes or freshly baked cookies. After about 5 minutes they were given a test consisting of impossible puzzles, with each group being monitored to see how long they persisted at trying to solve them. People who had resisted cookies, which everyone found harder then resisting radishes, had less sticking power at the puzzles (Journal of Personality and Social Psychology, vol 74, p 1252). Baumeister believes this is because we use up a store of willpower resources every time we make the effort to hold back or do something we don’t want to do. Exercising willpower is like exercising a muscle, he says, and it takes time for the resources used to be www.newscientist.com
Just say “no” Anti-drug messages that tell people to “just say no” may be missing an important point, according to Hugh Garavan of Trinity College in Dublin, Ireland. Some people may simply not be able to. Garavan has recently discovered that in cocaine addicts a network of frontal lobe regions involved in impulse control seem less active than normal. The ability to hold back all kinds of impulses was impaired, not just the desire to take drugs. When addicts took cocaine, though, it raised their brain activity and performance to normal levels. Until now, addiction research has focused
replenished. Making difficult decisions and coping with stress may deplete the same resources, also sapping willpower. He has since suggested that blood glucose levels are the key to keeping our willpower strong. By giving people a sugary lemonade drink before they completed a willpower exercise, he found that subsequent selfcontrol was not depleted in the same way as in those who had no drink or an artificially sweetened lemonade (Psychological Science, vol 19, p 255). “Conscious, effortful control uses energy,” he concludes. This could explain why all-encompassing health drives so often fail. Kicking the cigarettes may take all your available willpower, leaving little in the tank to fuel the new exercise regime and healthyeating plan. Given all this evidence that our ability to control ourselves is determined by biology, there may seem little point trying to change our ways. There are a few tricks, though, that
on reward and pleasure circuits, Garavan points out. What’s clear is that not only is the desire altered, but the impulse control too. What’s not clear is whether the damage is done by drugs, or whether those with impaired control are more likely to use them. Either way, there is evidence that even drugs that may be relatively benign in adults could be toxic to developing brain tissue. Since the impulse control networks continue to mature throughout adolescence, there’s now a physical reason to be concerned that drug exposure during the teens could increase the risk of lifelong addiction.
can help you improve it (see “Get a grip on yourself”, opposite) Brain imaging experiments by Garavan and colleagues have shown that practise can boost self-control in tests. This training seems to have the opposite effect to the ageing process – the areas of the brain involved seem to become more efficient with use, and less of the brain is called into action. However, Torkel Klingberg of the Karolinska Institute in Stockholm, Sweden, who has had some success with training working memory, has not found any evidence that self-control training effects last for the long term or outside the trained setting, at least not in young children. “Despite improvements on the trained task we did not find any transfer after training in 4 to 5-year-old children,” he says. Nevertheless, Baumeister has found that working on your self-control in one area of life can have a positive impact elsewhere. When he asked people to concentrate on correcting their posture every time they thought of it for a period of two weeks, he found that persistence in puzzle solving and other tests of self-control improved. Similar effects were seen when he asked people to adhere to a programme of exercise, suggesting that it doesn’t matter what routine you stick to, just sticking to something can improve your overall self-control. Clearly, though, improving your willpower the Baumeister way requires a certain amount to self-control to stick to the programme in the first place. However, according to psychologist Peter Gollwitzer of New York University and the University of Konstanz in Germany, there is another way to stay on track. Gollwitzer has come up with a method that will help even the worst procrastinator
to achieve a higher level of self-control. He stumbled across the idea while studying people’s states of mind during different stages of motivation and action. As part of an experiment, he asked some participants to write out exactly how they would complete a task, giving as much detail as possible about when and where they planned to do it. In subsequent studies he found that people who go through the trouble of making “when-where-and-how” plans were about three times more likely to actually act on their goals. He has since studied the effects of planning on all kinds of intentions and found that it works in almost every domain – from initiating actions and activities where there is an initial reluctance to get started, to altering emotional responses, controlling violence and overcoming stereotypes and phobias (Psicothema, vol 19, p 280). His methods have even improved impulse control in children with ADHD, and he plans to try them more extensively on drug addicts and people with other impulse control problems. According to Gollwitzer, planning works because it takes away some of the conscious mental effort. Even something as simple as saying you will go to the gym at 5pm on a specific day is a more successful strategy than intending to exercise once a week. Planning can turn a difficult conscious decision into an unconscious habit, which makes the whole process faster and more efficient without depleting energy levels. So it seems that, at last, the ultimate healthy, happy and successful lifestyle is in reach. All you have to do is make a watertight plan, keep your blood sugar up and then, as the saying goes, just do it. ●
www.newscientist.com/channel/being-human www.newscientist.com
13 September 2008 | NewScientist | 43