■ Because their ARAS gateway is typically somewhat closed at the baseline level, extraverts attempt to increase arousal, and perform better when able to increase cortical arousal into pleasant range.

Seek stimulation from environment

■ Introverts attempt to decrease arousal because their ARAS gateway is typically open wide, and they perform better when able to decrease cortical arousal into pleasant range

Seek to minimize stimulation from the environment

Extraversion & Arousal

■ Stelmack’s modification to Eysenck’s theory of Extraversion

Key difference is in reactivity/sensitivity to arousal

■ Under conditions with no or mild stimulation

No difference between introverts and extraverts

■ Under conditions with moderate stimulation

Introverts had larger or faster responses

■ As such, Eysenck was incorrect about baseline differences in arousal

Rather, there are differences in the arousal response

Stelmack, R. M. (1990). Biological basis of extraversion: Psychophysiological evidence. Journal of Personality, 58, 293-311

Geen’s test of Eysenck’s Theory of Extraversion

■ Extraverts and Introverts do Paired-Associates Learning Task with random background noise

“You Decide” condition: 1/3 Introverts and 1/3 Extraverts can adjust volume of noise
Preferred condition: 1/3 Introverts assigned to Introverts’ noise preference; 1/3 of Extraverts assigned to Extraverts’ noise preference
Opposite condition: 1/3 Extraverts assigned to Introverts’ noise preference; 1/3 Introverts assigned to Extraverts’ noise preference

Geen, R. G. (1984). Preferred stimulation levels in introverts and extroverts: Effects on arousal and performance. Journal of Personality and Social Psychology, 46(6), 1303-1312.

Extraversion & Noise Preference

■ Do Introverts and Extraverts have different preferences for background noise? Yes

■ On the tape recorder volume scale from 0 (silent) to 100 (very loud)

Extravert average = 54.2
Introvert average = 37.3

■ Side note: These sample sizes were quite small, and the only participants in this study were men (not an uncommon thing for older studies, but obviously problematic)

Follow-up studies included women and showed similar results

Performance

■ Do Introverts and Extraverts differ in performance when background noise is at preferred level?

Trials to Learn Rule

Opposite level?

■ Took more time to learn the rule in opposite condition, especially for introverts

Introverts Extraverts

Preferred Opposite

Arousal

■ Do Introverts and Extraverts differ in arousal level when in preferred and opposite noise level?

■ Higher arousal for introverts in both conditions, but especially in the opposite condition

Conclusions of Geen study

■ Introverts and Extraverts differ in preferences for background noise

– Extraverts preferred more noise than introverts

■ Each has moderate arousal and best performance when in preferred noise environment

■ Extraverts perform less well when in low arousal (introverts’) environment

■ Introverts perform less well when in high arousal (extraverts’) environment

Related Work: Furnham, Gunter, & Peterson (1994)

■ Effect of TV distraction on reading comprehension among introverts and extraverts

Both do better when no TV vs.

with TV

Performance of introverts plummets with TV distraction

Work from Home or Open-Plan Offices

■ Oseland, N., & Hodsman, P. (2018)

N = 517

■ Introverts reported being more impacted by noise

Self-assessed performance, stress, well-being, concentration and productivity

■ Work from home workers reported more control over their noise compared to open office plans.

Oseland, N., & Hodsman, P. (2018). A psychoacoustical approach to resolving office noise distraction. Journal of Corporate Real Estate.

Gray’s Reinforcement Sensitivity Theory

■ Behavioural Activation System (BAS):

Responsive to rewards and regulates approach behaviour
Active BAS produces impulsivity
Neurotransmitter = dopamine

■ Behavioural Inhibition System (BIS):

Responsive to punishment, frustration, uncertainty, and motivates ceasing, inhibiting, or avoidance behaviour.
Active BIS produces anxiety
Neurotransmitter = serotonin

Approach System (BAS)

■ Both Approach & Avoidance Based in Limbic System

■ For approach system (BAS)

In particular, the septal nuclei

& nucleus accumbens

■ Causes one to be sensitive to potential rewards & motivates reward seeking behaviour

When BAS active, one craves rewards (impulsive)
When BAS inactive, one is unmotivated

Inhibitory System (BIS)

■ Based in hippocampus,

although this region is mostly associated with memory, not just emotion

Amygdala, in the limbic system, is also key (vigilance response to info)

■ Sensitive to potential punishments & motivated to avoid them

When active, person is anxious

Individual Differences in BIS & BAS

■ Individuals differ in threshold for activating BAS (Activation system) and BIS (Inhibition system)

Some people more sensitive to reward than others

■ e.g., first day at new school (anticipation or ho hum?)

Some people more sensitive to punishment than others

■ e.g., final exam (anxious or calm?)

Assessing BIS & BAS in Humans

Carver & White (1994) Self-Report Measure

BIS: (Inhibition)

Even if something bad is about to happen to me, I rarely experience fear or nervousness. (R – reverse or opposite answer)
Criticism or scolding hurts me quite a bit.
If I think something unpleasant is going to happen I usually get pretty “worked up”.
I have very few fears compared to my friends. (R)

Assessing BIS & BAS in Humans

BAS: (Approach)

I go out of my way to get things I want.
I'm always willing to try something new if I think it will be fun
When I'm doing well at something, I love to keep at it
I will often do things for no other reason than that they might be fun.

Carver, C. S., & White, T. L. (1994). Behavioral inhibition, behavioral activation, and affective responses to impending reward and punishment: The BIS/BAS scales. J of Pers. & Soc. Psyc, 67, 319-333.

BIS & BAS: Daily Experience

■ Gable et al. (2000)

Daily diary study with college students

■ High BIS sensitive students

Experienced more negative emotions
More affected by negative events

■ High BAS sensitive students

Experienced more positive emotions
Experienced more positive events

Gable, S. L., Reis, H. T., & Elliot, A. J. (2000). Behavioral activation and inhibition in everyday life. Journal of Personality and Social Psychology, 78(6), 1135-1149.

BIS & BAS: Depression

■ Kasch et al. (2002)

People high in depression have higher BIS sensitivity and lower BAS sensitivity vs. people not depressed
People high in depression with lower BAS sensitivity showed less recovery 8 months later

Kasch, K. L., Rottenberg, J., Arnow, B. A., & Gotlib, I. H. (2002). Behavioral activation and inhibition systems

and the severity and course of depression. Journal of Abnormal Psychology, 111(4), 589-597

Updating Reinforcement Sensitivity Theory

■ Gray & McNaughton (2000): 3 systems instead of 2

■ BAS: Reward sensitivity (similar to Extraversion)

Motivation to approach potential rewards, impulsivity

■ BIS: Conflict sensitive (similar to Neuroticism, Anxiety)

Motivation to avoid punishment, frustration, decisions
Sensitive to uncertainty, choice dilemmas, novelty
No longer focus on punishment—more internal conflict

■ FFFS (Fight, Flight, Freeze System): sensitive to danger

Demands immediate response
Response to punishment or threat
Panic, Fear

Sensation Seeking

■ Sensation Seeking: Tendency to seek out thrilling, exciting activities, take risks, avoid boredom.

■ High sensation seekers are less tolerant of sensory deprivation

Require much stimulation to get to optimal level of arousal

■ Zuckerman’s Sensation Seeking Scale can be used to measure it

Moderate positive correlation between extraversion and sensation seeking

Boredom Research (somewhat related to arousal)

■ Wilson et al. (2014) study in Science

■ Abstract: “In 11 studies, we found that participants typically did not enjoy spending 6 to 15 minutes in a room by themselves with nothing to do but think, that they enjoyed doing mundane external activities much more, and that many preferred to administer electric shocks to themselves instead of being left alone with their thoughts. Most people seem to prefer to be doing something rather than nothing, even if that something is negative.”

■ Wilson, T. D., Reinhard, D. A., Westgate, E. C., Gilbert, D. T., Ellerbeck, N., Hahn, C., Brown,

C.L., & Shaked, A. (2014). Just think: The challenges of the disengaged mind. Science, 345, 75–77. http://doi.org/10.1126/science.1250830

Sensation Seeking

■ Monoamine Oxidase (MAO): Enzyme that maintains neurotransmitter levels

“Set the brakes” in the nervous system

■ High sensation seekers have low levels of MAO

Extra neurotransmitters in nerve cells, and overall nervous system

■ Important to consider biological factors for sensation seeking when it leads to problematic behaviours

Example: Gambling

Neurotransmitters and Personality

■ Dopamine: Associated with pleasure

Animals motivated to receive dopamine much like food rewards
Several drugs (e.g., cocaine) mimic dopamine, but reduce natural production

■ Serotonin: Low levels associated with depression and anxiety

Common anti-depressants prevent the reuptake of serotonin, making more serotonin available in the synapse for better transmission between neurons.

Neurotransmitters and Personality

■ Dopamine: Related to Extraversion

Also related to Openness in some recent research (in a different way—salience of information)

■ Serotonin: Related to Neuroticism

■ Biological systems and processes are complicated

Correlations between traits and absolute levels of a neurotransmitter can’t give you the full story

Neurotransmitters and Personality

■ Dopamine & Extraversion

Researchers have explored the number of dopaminergic neurons, and response to increasing dopamine with drugs
The reaction to dopamine differs, not baseline levels

■ Serotonin & Neuroticism

Anti-depressants (SSRIs, specifically) try to reduce reuptake, but don’t work for everyone
Some animal studies show direct increases in serotonin in hippocampus increases anxiety
Might be due to different facets of neuroticism