Self Control

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Self-control is the ability, on a moment by moment basis, to control one’s impulses and direct one’s attention in a goal directed manner.

Self-control is part what differentiates the child who is able to turn off the TV and focus on homework, and part of what differentiates the adult who is able to stick to a diet and control their weight, year after year.

How important is it, and in which domains? How can it be increased?

Those are the two main questions answered by the self-control studies of Angela Duckworth, which have been summarized on this page. Check back later for a more thorough accounting of self-control. I will be reading and incorporating research from additional scholars in the weeks and months to come.

Table of Contents

  1. Self-Control Predicts Weight Gain, Academic Achievement, & Intelligence
  2. Self-Control Interventions
  3. How Is Self-Control Measured?
  4. Scientific Findings

Self-Control Predicts Weight Gain, Academic Achievement, & Intelligence

Two studies with over 1,000 total children have found that self-control at a young age predicts future weight gain – the more self-controlled, the less likely the child ended up overweight.

One study found that self-discipline better predicted academic performance than intelligence. Another, of almost 2,000 children, found that self-control best predicted report card grades, while intelligence best predicted standardized achievement test scores.

Another study found that personality factors, perhaps levels of self-control, directly influence IQ scores – those with more motivation apply more effort during tests, leading to substantially higher scores.

Across many of these studies, self-control was found to be highly correlated with levels of the personality trait conscientiousness.

A more recent study found that self-control is useful across multiple domains: work, food, spending, drugs and alcohol, and exercise.

Self-Control Interventions

Given these and additional findings, it’s become more clear that self-control is important for goal achievement in many domains.

What then, can be done to increase levels of self-control?

Mental contrasting is the act of visualizing a desired future, and then visualizing the obstacles that stand in the way of that future being realized. Mental contrasting has been found to significantly increase goal achievement, first in adults, and now in children.

Implementation intentions is the act of defining what actions to take given a set of triggers (e.g. ‘when I’m in the kitchen at 6 pm, I will study; when I’m confused at work, I will ask for clarification). Implementation intentions has also been found to significantly increase goal achievement, first in adults, and now in children.

The combination of these techniques led children to complete 60% more practice questions over one of their summer breaks.

This is; however, just the beginning – there are dozens of techniques to be tested.

What techniques are best suited to which children? For what tasks? In what order? In what combination  Can these techniques be trained? Do they decrease task aversiveness, or increase willpower? Both? Can the application of high effort be paired with pleasure (e.g. learned industriousness)?

How Is Self-Control Measured?

There are a number of ways in which self-control is measured.

For children, the following combination of measures was often used:

  • A survey, filed out by parents and teachers, asking how well the child can inhibit behavior, follow rules, etc…
  • A survey, filed out by the child, asking them how much they agree with certain statements (e.g. ‘I do certain things that are bad for me, if they are fun’).
  • A discounting rate survey or task, in which the ability of the child to deal with their present desires in order to achieve future goals can be seen (e.g. ‘you can have one piece of candy now, or three next week’).

Scientific Findings

Self-Control & Academic Achievement

Self-discipline Outdoes IQ Predicting Academic Performance in Adolescents

Some combination of personality, intelligence, and environmental factors determines success.

Intelligence and environment are usually considered to have a much larger role than personality. This study shows that personality may play a larger factor in academic performance than previously thought.

Some background:

  1. “Greater ability to delay gratification measured at age 4 predicted higher academic and social functioning more than a decade later. (H.N. Mischel & Mischel, 1983; W. Mischel, Shoda, & Peake, 1988; Shoda, Mischel, & Peake, 1990).”
  2. “Wolfe and Johnson (1995) found self-discipline to be the only one among 32 measured personality variables (e.g., self-esteem, extraversion, energy level) that predicted college grade point average (GPA) more robustly than SAT scores did.”
  3. “Hogan and Weiss (1974) found that high self-discipline distinguished Phi Beta Kappa undergraduates from non Phi Beta Kappa students of equal intellectual ability.”
  4. “In two large samples of undergraduates, Tangney, Baumeister, and Boone (2004) found that self-discipline correlated positively with self-reported grades, as well as a broad array of personal and interpersonal strengths.”

The size of the effect of self-discipline on the short and long-term performance of young kids and college students may still be in doubt, but the idea that there is an effect should be taken more seriously.

What about with adolescents?

In this study, self-discipline better predicted the future GPA of two groups of eight-grade students. Those students with the highest IQ had a GPA only a few points higher than those with the lowest IQ (91 vs 85), but those with the highest self-discipline had a GPA almost 15 points higher than those with the lowest (93.5 vs 80.5).

The authors present the idea that much of what gets graded in school and converted into GPA is based off of effort, not intelligence. This study confirms that suspicion. In a later study, this hypothesis is further tested and further confirmed – GPA tests effort; standardized assessment (e.g. SAT) tests IQ.

Read more here.

What No Child Left Behind Leaves Behind: The Roles of IQ and Self-Control in Predicting Standardized Achievement Test Scores and Report Card Grades

This study tests the hypothesis that report cards and standardized assessments test different things – specifically, that report cards focus more on testing self-control, and standardized assessments on testing intelligence.

Their reasoning is that the individual components which build into a report card grade, like paying attention in class, doing homework, and showing effort, primarily require self-control.

On the other hand, standardized assessments often test things not taught in class. A person’s ability and motivation to learn things outside of class, they hypothesize, primarily depends on their level of intelligence. The model below illustrates this hypothesis visually:

Their first study, of 1,364 students over their middle school years, confirms this hypothesis –  self-control much better predicted report-card grades than IQ, and IQ much better predicted achievement test scores than self-control. It is unclear to me why self-control plays the small factor that is does in predicting standardized test scores – after all, even a smart person needs self-control to stay focused on learning skills and knowledge when outside of school.

In their second study, of 510 students, also over their middle school years, these results were replicated. In addition, it was found that most of the reason higher self-control translated into higher report-card grades was because of increased homework completion and improved classroom conduct.

Read more here.

Self-Discipline Gives Girls the Edge: Gender in Self-Discipline, Grades, and Achievement Test Scores

Using the same data as in this study, the idea that girls have higher average levels of self-discipline than boys was tested and confirmed.

Adolescent girls were found to have 5 to 20% more self-control than adolescent boys, explaining in part why they do better than boys in school. In this study, the women had, on average, a 14% higher GPA than the men.

Although this study raises the possibility that adolescent girls have more self-control than adolescent boys, many questions remain:

Is the difference biological or environmental?

How long does the difference persist? Into adulthood? Or is this merely a case of girls maturing ahead of boys, suggesting that over time the gap should diminish?

If the difference is environmental, can the effects be transferred to boys?

Read more here.

Establishing Causality Using Longitudinal Hierarchical Linear Modeling: An Illustration Predicting Achievement From Self Control

Dozens of studies have already established that personality can influence important life outcomes, like getting a good job, staying married, and doing well in school. However, these studies are rarely if ever experimental. As a consequence, hidden variables could be skewing the results.

This study improves the validity of using self-control to predict academic achievement. Although still not experimental, this longitudinal study uses hierarchical linear models (HLM), which can partially rule out the influence of time-invariant hidden variables.

In this four-year study of 189 fifth-graders, increases in self-control were found to predict increases in GPA (r=.18), after controlling for self-esteem, IQ, gender, ethnicity, and income. However, the relationship between average self-control and average GPA was three times stronger (r=.47). That is to say, GPA is moderately influenced by short-term changes in self-control, but a large portion of the difference between high-achieving students and low-achieving students can be explained by the differences in their average levels of self-control.

Read more here.

Role of Test Motivation in Intelligence Testing

IQ tests, in their ideal form, accurately measure intelligence.

In the real world, they don’t, for several reasons.

First, many portions of an IQ assessment test crystallized knowledge – that is, they test for facts that have already been memorized. Although knowledge is a component of intelligence, intelligence, as it is usually used, means, ‘how fast can this person learn?’

The Ravin’s Progressive Matrix overcomes a part of that problem by eliminating all words – allowing anyone of any culture of any reading level to complete the test.

There are still a few problems.

First, performance on these tests can be trained, much like how performance on the SAT can be trained and improved, even while the base level of knowledge does not increase.

Second, a number of personality factors influence how hard a person tries, in turn influencing their score.

This study wished to quantify the role of test motivation on test performance. Those participants who were incentivized to try hard (with money, candy, etc…) did better – incentives increased the IQ scores of individuals with below-average IQs at baseline by .96 SD, and .26 SD for individuals with above-average IQs at baseline. .96 standard deviations is huge – corresponding to 10 to 15 IQ points.

The fact that incentives made less difference for those with higher baseline IQ suggests that part of the reason they have a higher baseline IQ is because they can generate more intrinsic motivation, causing them to exert greater than average effort. That, in turn, suggests that the true spread of intelligence is more narrow than what the standard distribution suggests.

Read more here.

Self-Control & Weight

Self-controlled Children Stay Leaner in the Transition to Adolescence

Do levels of self-control in young children predict future weight status?

Maybe.

The level of self-control contained by an eight-grader four years earlier explains 8% of the variance of their weight. But after controlling for their BMI four years earlier, self-control explains just 1% of the variance of their weight.

This suggests that self-control starts to influence weight at an early age, because in addition to genetic and environment information, fifth-grade BMI contains most of the same information as fifth-grade self-control. However, that suggestion should be tested before self-control interventions are given to at-risk children; because, at least for now, the impact of self-control on weight among children seems to be statistically significant but still small.

Read more here.

Self-control as a Protective Factor Against Overweight Status in the Transition to Adolescence

“Children who were rated 1-point higher on a 3-point self-control scale were 26% less likely to be overweight as adolescents.”

Multiple factors determine a child’s weight status, of whether they are healthy or overweight. This study assessed whether self-control was one of those factors.

844 children were watched from age 9 to 15. Those who were more self-controlled at age 9 were significantly less likely to be overweight at age 15.

Although it’s not clear what kind of intervention could increase the self-control of 9 year olds, these results suggest that several interventions should be hypothesized and tested, given that self-control could help tame the obesity epidemic.

Read more here.

Self-Control Interventions

Mental Contrasting Facilitates Academic Performance in School Children

Given the increasing evidence that self-control influences academic performance, it is important to try to increase the self-control of children.

Of most interest are motivation strategies which have an immediate impact and don’t require a substantial time investment (e.g. unlike meditation).

This study evaluated the impact of mental contrasting on academic performance. Mental contrasting is the act of visualizing a desired future, and then visualizing the obstacles that stand in the way of that future being realized.

The authors propose that imagining a desired future may increase levels of desire, but not motivation – given the ease with which the desired future is visualized, subconsciously, the brain may think that the goal is easy to achieve, and does not require an increase in motivation.

On the other hand, mental contrasting has been shown in adults to increase goal achievement, because, as the authors propose, it increases both desire and motivation, as a carrot is hung in-front, but so to is a hill that first requires climbing.

In this study, students who were assigned to the mental contrasting condition scored 20 to 35% higher on a set of quizzes than those in the positive visualization condition. Presumably, mental contrasting increased motivation, which caused the students to study more, which in turn caused them to score higher.

A key question that remains – does mental contrasting increase self-control, decrease task aversiveness, or both?

Read more here.

Self-Regulation Strategies Improve Self-Discipline in Adolescents: Benefits of Mental Contrasting and Implementation Intentions

Given the increasing evidence that self-control influences academic performance, it is important to try to increase the self-control of children.

Of most interest are motivation strategies which have an immediate impact and don’t require a substantial time investment (e.g. unlike meditation).

This study evaluated the impact of the combination of mental contrasting and implementation intentions on academic performance.

Mental contrasting is the act of visualizing a desired future, and then visualizing the obstacles that stand in the way of that future being realized. Implementation intentions is the act of defining what actions to take given a set of triggers (e.g. ‘when I’m in the kitchen at 6 pm, I will study; when I’m confused at work, I will ask for clarification).

Both techniques have been found to be effective in adults. This study examined their combined effectiveness in an academic setting.

66 students were given a PSAT workbook, with 10 practice tests to be optionally completed during their summer break.

Students in the mental contrasting + implementation intentions condition completed 60% more questions than students in the control. It’s important not to get too excited – the results are unlikely to generalize without significant change to the experimental protocol. Still, this study shows the potential effectiveness of easy self-control techniques.

If I had answered 60% more questions on my PSAT workbook, I might have scored as well as my older sister (she got a perfect score…).

Read more here.

Miscellaneous

Resisting Everything Except Temptation: Evidence and an Explanation for Domain-Specific Impulsivity

Through a series of 3 studies, the idea that temptation can be domain-specific is explored. The authors bring up the example of Tiger Woods – of how he displayed paragon level self-discipline in most areas of his life, but was found to have succumbed to temptation over a dozen times in one specific area (Holly Sampson, etc…)

The first study showed that levels of self-control in one specific area do not directly correlate with levels of self-control in another. That is, people have a global level of self-control, and, for each domain, a domain-specific level of self-control. It is that combination that determines whether or not a person is able to fight off temptation.

This and the next two studies found that individuals on average, across all domains, have similar levels of self-control; however, in specific domains, may have drastically different levels of impulse control.

The second study showed that most of the difference in impulse control between different domains can be explained by the difference in their levels of temptation. While this result may seem intuitive, the hypothesis that differences in impulse control are driven by differences in perceived harm (e.g. it’s not so harmful to sleep around, but very harmful to eat hamburgers), was largely disproven – perceived harm had a statistically significant but still small effect.

The third study showed that for the same person, levels of temptation vary across particular domains – that even a chronic procrastinator or shopaholic could have tremendous control over their impulses to sleep around.

Read more here.

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