Mathematics · Allostatic load · Growth or scarring
Why the same stress strengthens some people and scars others.
Exercise is a stressor, and so is a bereavement. Some stress leaves people stronger; some leaves damage that outlasts it. This page extends the allostatic load model with the conditions that decide which.
A theoretical model with illustrative parameters. It is not fitted to data and says nothing about any individual.
What decides the outcome
- Control: whether a person can act.
- Dose: moderate challenge versus demand above capacity.
- Recovery: growth happens between episodes.
- Predictability: known stress sensitises less.
- Social context: support buffers and threat amplifies.
- Appraisal, timing and meaning-making alter persistence and response.
The growth window
Capacity grows when stress-driven demand stays below a ceiling set by capacity and falls away often enough to recover. Control, support and recovery widen the window; rumination shrinks it.
Build a scenario
Advanced model parameters
Interventions for the first stressor
Trajectories
Solid: current scenario · long dash: without interventions · short dash: no stressor.
Demand and capacity
Load
Capacity set point
“Growth” here means a higher capacity set point in the model. It is not the self-reported post-traumatic growth measured in questionnaires, which tracks real change poorly.
The growth window
Each letter marks an outcome: C collapse, S scarring, R resilience, G growth. The white outline is the current setting.
What each intervention does here
Simulated changes use illustrative effect sizes, not study effect estimates.
| Intervention | Lever | Direction | Evidence | Citation | Class before → after | ΔC0 change |
|---|
Attribution
Shapley values of extra load; negative values are buffers.
Four outcomes
Each run is compared with the same model without the stressor: growth raises the capacity set point, resilience returns it, scarring lowers it, and collapse leaves capacity in a depleted state.
Where interventions act
Interventions map to exposure, persistence, control, predictability, social threat, support, recovery or capacity. Only records whose citations have been checked and confirmed by a human appear publicly.
A caution about “post-traumatic growth”
Retrospective perceived growth tracks measured change poorly. This model uses a measurable definition: a higher capacity set point, seen as faster recovery from the next challenge.
How it fits the landscape
Capacity sets the depth of a person's basin on the landscape. Damage makes it shallower; growth deepens it.
Testing it
Repeated laboratory stress tests, training studies and cohorts with dated events can test whether a moderate, controllable challenge speeds recovery from the next one. See open problem 6.