Can contagious itch be affected by positive and negative suggestions?

Area of Science:

• Psychology
• Neuroscience
• Dermatology

Background:

• Contagious itch, or itch contagion, can be triggered by observing others scratch.
• Verbal suggestions can influence itch intensity, as demonstrated in placebo research.
• The impact of suggestions on contagious itch remains largely unexplored.

Purpose of the Study:

• To replicate findings that scratching and rubbing sounds elicit contagious itch.
• To investigate whether verbal suggestions can modulate the experience of contagious itch.
• To explore the potential neurobiological underpinnings of contagious itch and its modulation.

Main Methods:

• 140 healthy participants were exposed to audio fragments of scratching and rubbing sounds.
• Participants received positive, negative, or no specific suggestions regarding expected itch.
• Self-report measures assessed expected itch and actual itch sensation after auditory stimuli.

Main Results:

• Both rubbing and scratching sounds significantly induced itch across all participant groups.
• Scratching sounds elicited greater itch than rubbing sounds only in the control group.
• Verbal suggestions did not affect expected itch but modulated contagious itch in a non-hypothesized direction.

Conclusions:

• Short-term verbal suggestions may be insufficient to alter expectations regarding contagious itch.
• Contagious itch can be modulated by suggestions, but not always as predicted.
• Further research is needed to understand the neurobiological mechanisms linking contagious itch and nocebo effects.