Predicting Declines in Attention and Memory During a Prolonged Mental Task

This study will investigate whether heart activity and changes in the skin's ability to conduct electricity can help predict performance during a demanding computer task. These signals reflect how the body responds to mental effort. The main question is whether measurements taken at rest and near the beginning of the task help predict later accuracy, beyond information about sleep the previous night, current sleepiness, and initial task performance. Healthy young adults will attend one visit lasting approximately 50-60 minutes. Participants will complete a questionnaire and wear sensors that record heart activity and skin responses. After a five-minute resting measurement, participants will learn a computer task involving letters and numbers. The task requires remembering the previous letter and deciding whether numbers are odd or even. A short calibration will adjust the presentation speed to each participant. Participants will then perform the task for 16 minutes at the selected speed and rate their fatigue and the demands of the task. After these ratings, participants will rest quietly for five minutes and repeat the task for four minutes at the same speed. The researchers will also examine how performance, fatigue, and body responses change during the task and after rest. The study is intended to improve understanding of sustained mental effort and is not a medical diagnostic assessment.

Inclusion Criteria: * Age 18-30 years. * Good general health according to self-report. * Normal or corrected-to-normal vision and ability to read the letters and digits presented on the screen. * Ability to understand instructions in Polish and perform the computer task. * Provision of voluntary informed consent. Exclusion Criteria: * Neurological, psychiatric, or cardiovascular conditions that significantly affect participant safety, task performance, or heart rhythm. * Use of medications or substances that significantly affect heart rhythm, arousal, or cognitive performance. * Acute infection, fever, feeling unwell, or skin damage that makes sensor placement difficult. * Failure to understand the task after repetition of the instructions and practice, or unsuccessful calibration. * Caffeine or nicotine use within four hours, alcohol consumption within 24 hours, or intense physical exercise within 12 hours before the visit. * Absence or withdrawal of informed consent.