How did acute stress change responses to reward and loss cues?

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Extinction training creates a second, inhibitory memory trace and effectively reduces conditioned responding. Acute stress, however, inhibits retrieval of that extinction memory. It was unknown whether the same applies to other forms of associative learning, such as instrumental counterconditioning, in which previously learned associations are reversed and paired with the opposite valence.

This preregistered study investigated whether stress decreases retrieval of instrumental counterconditioning memories involving aversive and appetitive consequences. Fifty-two healthy men were randomly assigned to a stress or control group and took part in a two-day instrumental learning paradigm. In the first phase, they learned that pressing specific buttons in response to four neutral stimuli led to gaining or losing money. In the second phase, the contingencies for two stimuli were reversed through counterconditioning. One day later, participants underwent acute stress or a control condition before performing the same task, now without feedback about gains or losses.

Compared with non-stressed participants, stressed participants showed more approach behavior toward appetitive stimuli and less avoidance behavior toward aversive stimuli. The findings indicate that stress effects on memory retrieval differ depending on the associative learning approach in men. The researchers suggest these differences might relate to stress effects on decision-making and the different motivational systems involved.