ERP-waveforms starting at the presentation of the disambiguating adverb for dialogues containing violations (grey)

The caption for fig. 2 in that horrific study on Gricean brainwaves:

"ERP-waveforms starting at the presentation of the disambiguating adverb for dialogues containing violations (grey) and neutral dialogues (black) on a frontal (Fz) and a posterior electrode (Pz)."

Enough to have Grice's brain ...

It IS understood: they were Groeningen (in the Netherlands) undergrads, who did it for some course credit AND money.