Mental workload The ratio between a task’s demand and the persons’s capacity Too high workload leads to stress, reduced performance, errors Too low workload leads to boredom, efficiency loss Decrease In alpha associated with increased workload Increase in theta associated with higher workload Lower P300 amplitudes in higher workload RSME scale (Rating scale mental effort) not effortful(2) rather effortful(58) max at 150

N-back task Used to measure working memory capacity Have to say whether item is the same as the one presented n-trials ago. N=0 – just recognize target (easy) N=1 – recognize repeats (easy) N=2 – recognize repeats two back (hard) http://cognitivefun.net/test/4 3-back Demo here https://www.psytoolkit.org/experiment- library/experiment_nback.html

Alpha, theta and eye movement differences

Fz difference

FCz difference

Pz difference

ERP responses

ERP responses

Accuracy and Bitrate of Classifiers

Relative difficulty of the different classification tasks

Useful information is in the EEG

Concluding thoughts Workload is not just reflected by the N but by factors related to the subject also Workload for N=0 or 2 could be distinguished Workload for N=1 was in between and closer to N=0 Monitoring workload with P300 responses could be quite annoying (and increase workload by their presentation) Monitoring power in different frequency bands would be less intrusive