The Effect of Thermal Pain on Working Memory: Behavioral Evidence from the n-Back Task

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• Pain and working memory (WM) interact bidirectionally.
• Traditional research often treats pain as a distractor, not task-relevant content.

Purpose of the Study:

• To investigate if thermal sensations can be encoded and updated in working memory using an n-back paradigm.
• To explore the cognitive costs associated with processing thermal information in WM.
• To shift the paradigm from 'pain-as-interference' to 'pain-as-content' for studying nociceptive WM.

Main Methods:

• Nineteen healthy adults completed visual and thermal single n-back tasks.
• Cross-modal conditions with task-irrelevant distractors and a dual n-back task were employed across three load levels (1-, 2-, 3-back).
• Qualitative data on participant strategies were collected.

Main Results:

• Thermal cues resulted in lower accuracy and longer response times (RTs) compared to visual cues.
• Task-irrelevant thermal input prolonged RTs in the visual task under low load.
• Task-irrelevant visual input showed a trend-level improvement in thermal-task accuracy under high load, suggesting cross-modal effects.
• Participants reported transcoding thermal sensations into verbal or numerical labels.

Conclusions:

• Thermal sensations can be operationalized as mnemonic content within working memory.
• Processing thermal information incurs significant executive costs, primarily due to transcoding demands and resource competition.
• This approach provides a framework for studying nociceptive working memory and quantifying cognitive interference in clinical pain populations.