Abstract: In this study, we attempt to validate previous findings on extraversion-related differences in speed of sensorimotor processing and to extend them into Behavioural Approach System (BAS) subtraits within the framework of the revised Reinforcement Sensitivity Theory (rRST) of personality. Here, we will assess psychological traits of extraversion (E), four BAS facets (Goal-Drive Persistence, BAS-GDP; Reward Interest, BAS- RI; Reward Reactivity, BAS-RR; Impulsivity, BAS-I), 60 volunteeers. Stimulus-locked lateralized readiness potential (S-LRP), response-locked LRP (R-LRP), stimulus-locked and response-locked forearm electromyogram (S-EMG and R-EMG), and P3 components of the event- related potentials (ERPs), will berecorded during the performance of a two- choice Go/NoGo visual letter-digit discrimination task varying in task difficulty. We expect that high extraverts, relative to introverts and individuals high relative to low on BAS-RI, will be more likely to exhibit shorter S-LRP latencies and stimulus- and response-locked EMG latencies. Extraverts, relative to introverts, along with those high relative to low on BAS-RR and BAS-I, will exhibite smaller P3 amplitudes.
The present study could improve actual knowledge concerning the relations between sensorimotor processing and individual differences in personality. It would be the first to address the relations between sensory information processing and a multidimensional view of the Behavioral Activation System. In particular, this study would be one of the first to examine the association among central and peripheral motor response initiation, motor response execution and individual differences especially in the `wanting¿ facets of BAS (i.e., BAS-Reward-Interest and/or BAS-Goal-Drive-Persistence).
In addition, it would contribute to corroborate (or not) the view that peripheral and cortical premotor processes are relevant determinants of individual differences in extraversion and BAS-RI.
The present study, although may be considered a pilot study, could improve actual knowledge concerning the relations between sensorimotor processing and individual differences in personality. In particular, this study would be the first to address the relations between sensory information processing and a multidimensional view of the Behavioral Activation System. Overall, findings from previous studies using only one (mono-dimensional) BAS measure could have led, and often do have led, to ambiguous results. This study would be one of the first to examine the association among central and peripheral motor response initiation, motor response execution and individual differences especially in the `wanting¿ facets of BAS (i.e., BAS-Reward-Interest and/or BAS-Goal-Drive-Persistence).
In addition, the study would contribute to corroborate (or not) the view that peripheral and cortical premotor processes are relevant determinants of individual differences in extraversion and BAS-RI. Although research has demonstrated that dopamine plays a key role in the regulation of assertiveness and sensitivity to reward (i.e., `wanting¿ facet of Extraversion; Knutson and Cooper, 2005) we do not have electro-encephalic data that corroborate this hypothesis not only for extraversion but also for Reward-Interest and Drive components of the BAS, the approach components candidate to be associated to extraversion. Additionally, Brebner and Cooper (1985) have proposed that introverts take more time for stimulus analysis to experience larger stimulus-excitation, whereas extraverts, being "geared to respond", perform better at simple time demanding tasks. As the tasks get more difficult, or stimuli get more complex, introverts, being "geared to inspect'', gain an advantage. Our findings could contribute to verify the extent to which this hypothesis may be extended to high BAS-Reward Interest trait.
With regards to the specific procedure that we would use, our study can contribute to clarify central and peripheral functioning in the case in which the probe stimulus of the task is more difficult to decipher. Previous studies using visual letter discrimination tasks and pure-tone discrimination tasks have found results that suggest that extraverts are less efficient than introverts in the processing of stimulus signal to respond (Stahl and Rammsayer, 2004, 2008; Houlihan and Stelmack, 2011), but authors have clearly stated that further research to determine whether their findings of longer S-LRP for extraverts holds when the informative stimulus is difficult to decipher. In our study, both easy and difficult visual letter-digit Go/NoGo discrimination tasks could be more demanding relative to those used in the above studies.
Finally, form a more general perspective, our study could contribute to validate the rRST theory , a theory that may be especially informative of the relationship between dimensional nature of the BAS and clinical disorders as vulnerability to first onset of bipolar spectrum disorders, as well as, to differentiate anxiety disorders from fear disorders (see e.g., Alloy et al., 2012; Bijttebier et al., 2009). Addressing the above mentioned research questions is important from any clinical, measurement, practical standpoint.