|dc.description.abstract||This thesis was conducted in order to investigate two issues: (1) how sensitive
event related potentials (ERPs), and more specifically the medial frontal negativity and
the P3 components, are to the valence and magnitude of reward-related stimuli, and (2)
whether individual differences have an effect on the sensitivity of these ERP components
to these characteristics. This was investigated using two reward-related paradigms.
In the "pure gambling task" participants were asked to choose between two cards,
each containing varying dollar amounts (large or small). The outcome of the choice (i.e.,
win or loss) was revealed after the choice was made. Additionally, participants were
shown whether the non-chosen card would have been a win or a loss. In the "simple
response task", participants were presented with five cues (large win, large loss, small
win, small loss or zero) that labelled the trial as either a potential win, a potential loss or
no change. Following the cue, a target appeared on the screen and the participant's task
was to press the response key while the target was still visible. A success led to a win
(gain in money) or no loss (no change) depending on the cue. Thirty participants
completed both tasks; afterwards they filled out a set of questionnaires measuring
personality and other individual differences relating to risk-taking behaviour.
The results of both tasks showed that ERP components can differentiate between
the valence and magnitude of reward-related stimuli, although no single component was
uniquely related to either of the characteristics as previous suggested in the literature.
Additionally, the context of the stimulus presentation (e.g., the task structure, condition
within the task) affected the relationships between the ERP components and stimulus