Graduation Year

2016

Document Type

Thesis

Degree

M.A.

Degree Name

Master of Arts (M.A.)

Degree Granting Department

Psychology

Major Professor

Geoffrey Potts, Ph.D.

Committee Member

Chad Dubé, Ph.D.

Committee Member

Thomas Sanocki, Ph.D.

Keywords

Event-Related Potential, MFN, FRN, P1, N1, RT

Abstract

The current study used event-related potentials (ERPs) to investigate how motivational salience in the form of expectation violation influences spatial attention. The medial frontal negativity (MFN) ERP indexes expected value, being negative to unexpected punishments and positive to unexpected rewards. The P1 and N1 ERPs index spatial attention, being larger to stimuli in attended locations. This design attached motivational value to locations by making one visual hemifield economically rewarding (greater probability of a rewarding outcome) and the other punishing (greater probability of a punishing outcome). Keypresses to a dot probe following a reward-signifying stimulus were awarded money if correct, and penalized following a punishment-signifying stimulus if incorrect. We predicted that salience would be attached to visual hemifield, thus the MFN would be most negative to punishing outcomes in the rewarding hemifield and most positive to rewarding outcomes in the punishing hemifield. We also predicted that attention would be allocated to a location where expectation was violated, thus the P1 and N1 ERPs would be larger and RTs (reaction times) faster to dot probes appearing in the same side as an outcome that violated expected value. In a sample of 36 participants, there were no significant effects on the MFN, although the means were in the predicted direction, suggesting a lack of power. Contrary to our hypothesis, keypresses were slower, P1 smaller, and N1 larger to probes opposite the location where an expectation violation occurred. This suggested that expectation violation did not direct attention to a particular location, but produced general interference.

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