Beyond expectations: nocebo suggestion affects cognitive performance in older adults

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• Placebo and nocebo effects are established in pain and motor control but their influence on cognition is less understood.
• Understanding these effects is crucial for developing interventions, particularly for older adults experiencing cognitive decline.
• The possibility of inducing these effects remotely, without direct interaction, requires investigation.

Purpose of the Study:

• To investigate if verbal suggestions can induce placebo and nocebo effects on cognitive performance in healthy older adults.
• To examine both objective and subjective cognitive changes in an online setting.
• To explore the dissociation between subjective expectations and objective performance.

Main Methods:

• Healthy older adults (65-80) were randomly assigned to control, placebo, or nocebo groups.
• Participants underwent an auditory and visual oddball task before and after an inert acoustic intervention.
• Verbal suggestions about the intervention's potential to enhance or impair cognition were given prior to exposure.

Main Results:

• The nocebo group exhibited impaired cognitive performance post-intervention, aligning with negative suggestions.
• The placebo group reported positive expectations and perceived benefits but showed no objective performance improvement compared to controls.
• A dissociation was observed between subjective beliefs and objective performance, particularly in the placebo group.

Conclusions:

• Nocebo effects on cognitive performance are demonstrable in older adults even in remote, online settings.
• Placebo effects in this context were primarily subjective, suggesting motivation and individual differences are key for objective enhancement.
• The findings underscore the nuanced nature of placebo and nocebo effects on cognition, especially in virtual environments.