The U-Curve of Plasticity and Openness

Opening Question:

Can interventions (exercise, psychedelics, therapy, education) be periodized — like strength training — to cycle between plasticity phases (exploration, rewiring) and stability phases (consolidation, identity)? 

Can we change our personalities?

1. Normal Distributions and Selection Pressures

Traits that fall into bell curves across populations often reflect balancing selection.

• Too little → maladaptive rigidity.
• Too much → maladaptive instability.
• Middle range → best fit for most environments.

This is not coincidence but evolutionary pressure: the “golden medium” sustains group and individual viability.

2. Trait Openness: Double-Edged Novelty

• Benefits of higher openness:
• Curiosity, creativity, tolerance for ambiguity.
• Exploration of new environments, ideas, and technologies.
• Costs of excessive openness:
• Susceptibility to distraction.
• Instability in commitments.
• Association with schizotypy and risk of psychosis.

Openness follows a U-shaped fitness curve: valuable in moderation, destabilizing in excess.

3. Neuroplasticity: Flexible but Fragile

• Benefits of higher plasticity:
• Faster skill acquisition.
• Recovery from injury or trauma.
• Adaptability under rapid change.
• Costs of excessive plasticity:
• Prior learning weakened or overwritten.
• Circuits destabilized by too-frequent rewiring.
• Links to dissociation, mood disorders, and excessive synaptic pruning.

PTSD exemplifies maladaptive plasticity: traumatic memories become over-consolidated. Psychosis may involve excessive synaptic turnover.

4. The Dialectic Balance

Openness and plasticity operate like volume knobs:

• Too low = rigidity, stagnation, dogmatism.
• Too high = chaos, fragility, instability.
• The optimal setting shifts with environment:
• Stable, tradition-bound contexts may favor lower openness.
• Rapidly shifting, innovation-rich contexts may favor higher openness.

5. Provisional Conclusion

Plasticity and openness are not “more is better” traits.
They are context-sensitive balances maintained by selection pressures.

• Evolutionary wisdom: keep them distributed across a range in populations.
• Therapeutic wisdom: seek temporary, targeted boosts (plasticity windows for learning or healing), followed by consolidation into stability.