Teen HRV and Risk Taking Under Stress

ISEF Category: Behavioral and Social Sciences

Subcategory: Behavioral Neuroscience  ·  Difficulty: Advanced  ·  Setup: School Lab  ·  Time: Full Year

The Hook

A racing heart does not always mean you feel scared. Sometimes the tiny gaps between beats tell you more than a survey answer does. Your project asks whether that body signal can predict who takes bigger risks on the Balloon Analogue Risk Task after stress. That gives you a direct link between physiology, behavior, and teen decision-making.

What Is It?

HRV, or heart rate variability, means the tiny shifts in time between heartbeats. A higher or lower HRV pattern can show how your body responds to pressure, calm, or recovery. A Polar H10 chest strap can capture that pattern well enough for a student project, then you can compare it with what a teen says on an anxiety survey.

The Balloon Analogue Risk Task, or BART, is a game-like test of risk taking. You pump a virtual balloon to earn points, but if you push too far, the balloon pops and you lose that round. Your question is whether stress HRV predicts those choices better than self-reported anxiety does, which turns the project into a test of whether the body or the survey gives the stronger clue.

Why This Is a Good Topic

This is a strong science fair topic because you can measure both body data and behavior, then compare them with a clear statistical model. It connects to stress, teen decision-making, and mental health, so the real-world link is easy to explain. You can learn how to collect physiological data, handle repeated measures, and test whether one predictor adds value beyond another.

Research Questions

• How does HRV during a stress task relate to later BART pump counts?
• What is the effect of self-reported anxiety on subsequent risk taking on the BART?
• Does HRV predict BART performance better than anxiety after controlling for age and baseline risk tolerance?
• To what extent does sex or grade change the link between stress HRV and risk taking?
• Which HRV window, baseline, stress response, or recovery, best predicts later BART choices?
• How does within-person change in HRV across sessions relate to within-person change in risk taking?

Basic Materials

• Polar H10 chest strap heart sensor
• Laptop or desktop computer
• Balloon Analogue Risk Task software or task file
• Anxiety survey form or online questionnaire
• Consent and assent forms
• Spreadsheet for data logging
• Quiet room for testing
• Digital timer

Advanced Materials

• Polar H10 chest strap heart sensor
• Three-lead ECG system for validation
• Event marker or trigger sync setup
• PsychoPy-ready task computer
• Secure encrypted data storage drive
• Backup chest straps
• Quiet testing room with controlled lighting
• Statistical software for multilevel modeling

Software & Tools

• Polar Beat: Records Polar H10 data and exports heart rate traces for analysis.
• PsychoPy: Runs the Balloon Analogue Risk Task and records trial-level choices.
• RStudio: Fits multilevel models and compares HRV and anxiety as predictors.
• jamovi: Gives a second, point-and-click way to check the same model.
• Google Sheets: Organizes participant timing, survey scores, and file names.

Experiment Steps

1. Define whether you will predict risk taking from stress reactivity, recovery, or both.
2. Choose one BART version and keep the task settings fixed for every participant.
3. Set your HRV window rules before you collect data, so the heart signal and task timing line up.
4. Plan your comparison model, including anxiety, age, and any other control variables.
5. Decide how you will handle missing data, outliers, and repeated measurements before you run the statistics.
6. Check whether the HRV model adds explanatory power beyond self-report, then test whether the result repeats in subgroups.

Common Pitfalls

• Using a wrist sensor instead of a chest strap, which adds motion noise and weakens short HRV windows.
• Treating heart rate and HRV as the same thing, which can flip the meaning of your predictor.
• Changing the BART instructions or payout frame between sessions, which changes risk behavior for reasons unrelated to stress.
• Measuring anxiety after the task, which mixes the stress response with the outcome you are trying to predict.
• Running one row per participant in a simple regression, which ignores repeated trials and hides within-person variation.

What Makes This Competitive

A class-level version stops at a simple comparison. A stronger project tests whether HRV adds predictive power beyond anxiety, then uses a multilevel model that respects repeated decisions inside each participant. You can push it further by checking subgroup effects, adding control variables, and testing whether the result holds across different stress windows. That kind of design shows real statistical thinking, not just data collection.

Project Variations

• Compare stress HRV against baseline HRV instead of self-reported anxiety to see which better predicts later BART risk.
• Test whether HRV predicts risk taking more strongly after a social stressor than after a quiet waiting period.
• Swap the BART for a delay discounting task to see whether the same pattern shows up in another decision test.

Learn More

• PubMed: Search review articles on heart rate variability, stress, and adolescent risk taking.
• NIH PubMed Central: Read free full-text studies on psychophysiology and decision making.
• PsychoPy Documentation: Find open-source instructions for building a Balloon Analogue Risk Task.
• R for Data Science: Free online book for cleaning data and building multilevel models with R.
• Open Science Framework: Find preregistration templates and shared analysis workflows.