Stable developmental conditions can conceal organisational dependencies that become visible when development is perturbed. When a developmental trajectory proceeds without substantial disruption, the contribution of particular regulatory, compensatory, reconstructive, or environmental relations may be difficult to distinguish.
Perturbation can reveal these dependencies. Nutritional disruption, injury, environmental instability, developmental stress, mutation, and ecological change may expose processes involved in regulation, compensation, developmental flexibility, repair, or other forms of reorganisation.
The evidential value of perturbation does not depend on successful recovery. A system may compensate, recover, or establish an alternative developmental trajectory; it may also become redirected, destabilised, arrested, dysfunctional, or non-viable. Differences among these outcomes can help establish which dependencies matter to the developmental process or transition being investigated.
In APS, perturbation is therefore diagnostically informative rather than merely disruptive. By altering or removing conditions on which a developmental process depends, perturbation can help identify the organisation required for particular trajectories or outcomes without presupposing that this organisation normally guarantees continuity or viable persistence.
Key point: perturbation can reveal developmental organisation by exposing the dependencies on which particular developmental processes, transitions, and outcomes depend.