Acute stress selectively impairs learning to act.

Area of Science:

• Neuroscience
• Behavioral Science
• Psychology

Background:

• Stress significantly impacts instrumental learning processes.
• Pavlovian associations (reward/punishment) influence choices alongside instrumental learning.
• The effect of stress on instrumental learning via Pavlovian biases is not well understood.

Purpose of the Study:

• To investigate if stress impacts instrumental learning through action-specific or valence-specific Pavlovian biases.
• To determine how stress modulates the interplay between instrumental learning and Pavlovian associations.

Main Methods:

• 60 human participants underwent either a stress induction (socially-evaluated cold pressor test) or a control condition.
• Participants engaged in a task where outcome valence (reward/punishment) and action (go/no-go) were orthogonalized.
• Pupillary responses were monitored to assess physiological correlates of learning.

Main Results:

• Stress specifically impaired learning to produce an action, regardless of the outcome's valence.
• This impairment aligns with Pavlovian associations linking punishment to inaction.
• Stressed individuals exhibited reduced pupillary responses to action, suggesting a noradrenergic role.

Conclusions:

• Stress selectively hinders action-learning, potentially due to an overemphasis on Pavlovian-driven inaction.
• The findings suggest stress-induced deficits in action production are linked to noradrenergic system activity.
• This research clarifies how stress modulates decision-making by affecting action-oriented learning.