The placebo effect in reading performance: A cross-over experimental study

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• Placebo and nocebo effects are known to influence perceptual and sensorimotor functions by altering brain chemistry and circuitry.
• The impact of these effects on higher-level cognitive processes like reading remains less understood.

Purpose of the Study:

• To investigate whether placebo and nocebo effects can modulate high-level cognitive functions, specifically single word reading and pseudoword decoding.
• To examine the role of explicit and implicit expectation induction on reading performance.

Main Methods:

• A within-subject experiment involving 102 young adults wearing sham glasses.
• Induction of positive and negative expectations through verbal instructions and computerized feedback.
• Measurement of subjective effects, personality traits (Big Five), pupil size, and heart rate.

Main Results:

• Explicit placebo expectations significantly enhanced word and pseudoword reading speed.
• Negative expectations did not show a significant impairment in reading speed within the study's task duration.
• No significant differences were found in heart rate or pupil size between placebo and nocebo conditions.
• Participant-reported subjective effects indicated perceived influence of the sham glasses on performance.

Conclusions:

• Placebo effects can positively modulate high-level cognitive tasks such as reading speed.
• The findings suggest a need to consider and harness placebo effects in clinical settings and reading interventions.
• Further research is needed to explore potential nocebo effects in tasks of longer duration.