Task-irrelevant decorative pictures increase cognitive load during text processing but have no effects on learning or...

Area of Science:

• Cognitive psychology
• Educational technology
• Neuroscience

Background:

• Decorative pictures (DP) are often included in multimedia learning materials but are typically not task-relevant.
• Their impact on learning performance is often mixed, with potential for distraction.
• Understanding the cognitive load associated with DP is crucial for optimizing multimedia design.

Purpose of the Study:

• To investigate the effects of decorative pictures (DP) on cognitive load during text reading and working memory tasks.
• To assess the utility of electroencephalogram (EEG) alpha frequency band power and pupil dilation as measures of cognitive load.
• To examine how the presence and congruency of DP influence cognitive load and attentional focus.

Main Methods:

• Participants performed text reading and n-back working memory tasks under four conditions manipulating the presence and congruency of DP.
• Cognitive load was measured using electroencephalogram (EEG) theta and alpha frequency band power, and pupil dilation.
• Attentional focus was assessed via fixation count, mean fixation duration, and transition count from eye-tracking data.

Main Results:

• Decorative pictures (DP) did not significantly affect behavioral performance or subjective emotional-motivational ratings.
• However, DP consistently increased cognitive load, evidenced by higher EEG alpha frequency band power and subjective effort ratings in both tasks.
• EEG alpha frequency band power proved to be a reliable and sensitive proxy for cognitive load, differentiating between global and local load.

Conclusions:

• Decorative pictures (DP) increase cognitive load during learning tasks, despite not affecting behavioral outcomes.
• EEG alpha frequency band power is a valuable and sensitive measure for assessing cognitive load in multimedia research.
• Combining EEG with eye-tracking offers a robust approach for studying cognitive processes in multimedia environments.