BIS/BAS

• BIS/BAS


  Behavioural Inhibition System / Behavioural Approach System
• Eysenck's Model of Personality


  • Initial model consisted of two independent dimensions: Extraversion (vs. Introversion) and Neuroticism (vs. Emotional stability)
  • Later added a 3rd independent dimension: Psychoticism (vs. 'Normality')
• Eysenck's Model says our ability to change our personality is thought to be restricted by our biological basis of personality, estimated at 20-25% capacity for change
• The human brain

  • Has two mechanisms: Excitatory (alert & active) and Inhibitory (inactivity & lethargy)
  • Needs to maintain balance
  • Regulated by the Ascending Reticular Activating System (ARAS)

  
• Arousal system


  Located in the brainstem, manages incoming information from the environment, maintains alertness
• Introverts


  Have a reticulo-cortical system that leads to higher arousal levels in the cerebral cortex
• Neurotics


  Have a reticulo-limbic system that leads to higher arousal to emotional stimuli, especially when stressed

  
• Gray's BAS/BIS Theory


  • Biological mechanisms approach things they desire, and move away from things they fear
  • Personality based on the interaction of three basic brain systems: Behavioural Approach System (BAS), Behavioural Inhibition System (BIS), and Fight-Flight-Freeze System (FFFS)
• Behavioural Approach System (BAS)


  Motivation to approach, sensitive to conditioned reward stimuli, associated with impulsivity & positive affect

  
• Behavioural Inhibition System (BIS)


  Motivation to avoid, sensitive to conditioned punishment stimuli, associated with anxiety

  
• Fight-Flight-Freeze System (FFFS)

  Sensitive to unconditioned (threatening) stimuli, associated with negative affect

  
• Strong BAS reactivity (impulsive)


  Responds well to rewards, poorly to punishment
• Strong BIS reactivity (anxious)


  Responds well to punishment, poorly to reward
• Revised Gray & McNaughton (2000) model


  • BAS sensitive to conditioned and unconditioned reward stimuli, related to anticipatory pleasure emotions
  • FFFS natural motivations following threat, sensitivity to conditioned and unconditioned aversive stimuli, related to fear
  • BIS resolution of conflict between FFFS and the BAS, goal is to resolve conflict & bring organism to state of non-conflict, acts as alarm signal using anxiety, risk assessment
• Anxiety is linked to rumination and vigilance as a way to reduce cognitive and emotional conflict (BIS)
• Cherbuin et al. 2008 study found a positive association between hippocampal volume and BIS sensitivity, and (to a lesser degree) with BAS sensitivity, supporting the Gray & McNaughton 2000 model
• The BAS-dysregulation model of bipolar disorders helps explain the role of the BAS in bipolar spectrum disorders, involving connections between the limbic system and prefrontal cortex structures and reward-sensitive dopamine neurons