Brain responses to structural violations in music and language

Finding from Patel et al. (1998): violations of syntactic expectancies in music and language yield a shared neural response: a P600.

Methodology: Event-related potentials (ERPs), measured using electroencephalography (EEG)

• EEG: record electrical activity of brain
• ERPs: look for systematic patterns of electrical activity that occur at systematic time relationships to some event

For an intro to ERP, try Luck (2005): An Introduction to Event-Related Potentials and Their Neural Origins.

• EEG setup diagram from https://i.imgur.com/ZrmxJRu.jpg

• John Kingston under the net

  

• Locations of electrodes, from https://i2.wp.com/neurologiclabs.com/wp-content/uploads/2013/12/EEG.gif?ssl=1

Sample ERP experiment: Luck (2005, p. 8)

• Subjects view sequences composed of 80% Xs and 20% Os and press different buttons, depending on whether they see an X or an O
• Marker codes give time of onset of the events, e.g., when an X appears or when an O appears.

• Look at electrical activity relative to the marker codes

• Average the electrical activity at each electrode over all Os you get from many, many trials, and for all Xs
• Look for systematic patterns of average electrical activity that occur time-locked to event, called components

P600 component

In the "violation" paradigm, one measures the difference in response to a stimulus that contains a violation of some expectancy, to a baseline comparison, in each case at some point in time after the stimulus presentation.

A P600 is a positive-going difference (deflection) approximately 600 msecs. after the relevant event.

Language - music study: Patel et al. (1998)

Linguistic examples:

Musical examples:

A Musical phrase with an in-key target chord

B Musical phrase with a nearby-key target chord

C Musical phrase with a distant-key target chord

Difference waveforms for C vs. A for music (dashed line) and language (solid line) from one point on the scalp (part of Figure 7).

From the abstract:

A within-subjects design using 15 musically educated adults revealed that linguistic and musical structural incongruities elicited positivities that were statistically indistinguishable in a specied latency range.

Interesting further reading: Psyche Loui et al. (2016) on jazz musicians (blue line), non-jazz musicians (red line), and non-musicians (black line). Difference waves on high vs. low expectancy.