Mental Skills Training: goals, imagery and pressure practice (education only)

01

Reading the evidence one level deeper

In simple words

Imagine two bags of marbles. If the average marble in one bag is only a little bigger, you could still pull a small one from the "bigger" bag. Studies are like that: the average may be better, but your result can differ. We look at the average and at how sure we are.

Before this course: Sport Psychology Basics (course 10.9). You should know what an effect size is (about 0.2 small, 0.5 medium, 0.8 large, as rough rules of thumb), that mental skills are not treatment, and where the crisis lines are.

Key facts

Cohen's d (and the similar Hedges' g) = difference between two group averages divided by the spread of the scores. Example (made-up, checked in Python): group A, who set practice goals, averages 8.1 out of 10 on a serve test and group B averages 7.5. With a spread of 2.0, d = 0.6 / 2.0 = 0.3, a small effect.
A confidence interval (CI) is a range where the true average probably is. A narrow range means more certainty. Example from this course: pressure training meta-analysis, g = 0.67 with a 95% CI of 0.43 to 1.12. The range is wide, so "moderate, maybe larger" is a safer sentence than "0.67".
A plain translation (if scores are roughly bell-shaped): d of 0.5 means the average person in the treated group scores higher than about 69% of the comparison group. For d = 0.2 it is about 58%, for d = 0.67 about 75%, and for d = 0.8 about 79% (standard normal formula, checked in Python). Even a "medium" effect leaves a lot of overlap, so some people in the comparison group do better than some people who used the skill.
Averages hide individuals. A mental skill may help one player a lot and another player not at all. This is why you measure your own results (lesson 7).
Correlation is not cause. If teams with high confidence also win more, it does not prove confidence caused the wins. Winning can build confidence too.
Where studies are weak: small groups, short studies, lab tasks instead of real matches, and unpublished "no result" studies that never appear in a meta-analysis.
Words to watch for in claims: "guaranteed", "proven for everyone", "unlock your potential in days". Honest wording is "may help", "on average", "small to moderate".
Order of importance: training, rest, sleep and coaching first; mental skills add a little on top.

What you read	Safer way to say it
"Imagery boosts performance by 43%"	"On average, studies found a medium effect (d about 0.43); the effect is not a percent"
"Goal setting works"	"On average, a small to moderate effect, depending on goal type and how it is used"
"Pressure practice cures choking"	"It may help; evidence from real competitions is limited"

Step by step

Pick a claim you have seen about a mental skill (an ad, a video, a social media post).
Find the number, if any: is it an effect size, a percent or just a story?
Ask four questions: how many people, what kind of task, was there a comparison group, and where was it tested?
Rewrite the claim in honest words with "may" and "on average".
Write what you could measure yourself to test it (for example, first serves in out of 20).
Check: your rewritten claim has no "guaranteed", and you named one thing you will measure.

LESSON 01Reading the evidence one level deeper

LESSON 01 / ANIMATED LESSON / AI VOICE00:00 / 01:00

Voice

Read the video script

[Host] "Mental skills are tools, not magic. Let us read the numbers honestly."
[Text on screen: Effect size d] "Effect size d says how big a difference is. Zero point two is small, point five is medium."
[Text on screen: Averages hide people] "A medium effect still leaves a lot of overlap. Some people gain a lot, some gain nothing."
[Text on screen: Correlation is not cause] "Confident teams win more, but winning also builds confidence."
[Host] "Say may help, on average, and then measure your own results."

Try it now

Take one mental skill claim you have seen online and rewrite it in honest words. Write one thing you could measure to test it on yourself.

ClaudeStuck? Copy a ready-made prompt for Claude

Copy this, open Claude, paste it, and Claude will walk you through the lesson step by step.

For a grown-up: Claude is for adults (18+). Copy this, paste it into Claude, and use the answer to explain the lesson to your child.

I'm learning "Mental Skills Training: goals, imagery and pressure practice (education only)" on The Future Market. Lesson 1: "Reading the evidence one level deeper".

What the lesson teaches:
- Cohen's d (and the similar Hedges' g) = difference between two group averages divided by the spread of the scores. Example (made-up, checked in Python): group A, who set practice goals, averages 8.1 out of 10 on a serve test and group B averages 7.5. With a spread of 2.0, d = 0.6 / 2.0 = 0.3, a small effect.
- A confidence interval (CI) is a range where the true average probably is. A narrow range means more certainty. Example from this course: pressure training meta-analysis, g = 0.67 with a 95% CI of 0.43 to 1.12. The range is wide, so "moderate, maybe larger" is a safer sentence than "0.67".
- A plain translation (if scores are roughly bell-shaped): d of 0.5 means the average person in the treated group scores higher than about 69% of the comparison group. For d = 0.2 it is about 58%, for d = 0.67 about 75%, and for d = 0.8 about 79% (standard normal formula, checked in Python). Even a "medium" effect leaves a lot of overlap, so some people in the comparison group do better than some people who used the skill.
- Averages hide individuals. A mental skill may help one player a lot and another player not at all. This is why you measure your own results (lesson 7).
- Correlation is not cause. If teams with high confidence also win more, it does not prove confidence caused the wins. Winning can build confidence too.
- Where studies are weak: small groups, short studies, lab tasks instead of real matches, and unpublished "no result" studies that never appear in a meta-analysis.
- Words to watch for in claims: "guaranteed", "proven for everyone", "unlock your potential in days". Honest wording is "may help", "on average", "small to moderate".

The exercise I'm working on:
Take one mental skill claim you have seen online and rewrite it in honest words. Write one thing you could measure to test it on yourself.

I'm stuck. Please:
1. Explain the main idea in plain, simple words with one everyday example.
2. Walk me through the exercise one small step at a time. Ask me what I've done so far before giving the next step.
3. Don't just give me the final answer. Help me do it myself, and check my work when I share it.
4. This is for learning only. Remind me to check with a licensed professional before I make a real decision about my own money, health or legal situation.

I'm a parent helping my child (about 8 years old) with a lesson called "Reading the evidence one level deeper" from the course "Mental Skills Training: goals, imagery and pressure practice (education only)".

Here's what the lesson says:
Imagine two bags of marbles. If the average marble in one bag is only a little bigger, you could still pull a small one from the "bigger" bag. Studies are like that: the average may be better, but your result can differ. We look at the average and at how sure we are. Before this course: Sport Psychology Basics (course 10.9). You should know what an effect size is (about 0.2 small, 0.5 medium, 0.8 large, as rough rules of thumb), that mental skills are not treatment, and where the crisis lines are.

The activity:
Take one mental skill claim you have seen online and rewrite it in honest words. Write one thing you could measure to test it on yourself.

Please explain this so an 8-year-old understands: short sentences, a fun everyday example, and no hard words.
Then give me 3 simple questions I can ask my child to check they understood, and a way to do the activity together, one tiny step at a time.
Keep it general and educational. This is not advice for a real situation.

Open Claude

Sources

Interpreting Cohen's d (0.2, 0.5, 0.8 are rough conventions; other fields use other scales): easystats.github.io/effectsize/reference/interpret_cohens_d.html
Pressure training meta-analysis (g = 0.67, 95% CI 0.43 to 1.12): Low and colleagues, Sport, Exercise, and Performance Psychology, 2021: doi.org/10.1037/spy0000202
The percent translations and the example are calculated in Python from the standard normal curve.

My notes

I learned this

02