Dark Side of Personality & Human Evolution

Features of Psychopathy (Cleckley, 1941)

  • Superficial charm & good intelligence.
  • Absence of delusions.
  • Lack of anxiety.
  • Unreliability.
  • Untruthfulness and insincerity.
  • Lack of remorse and shame.
  • Inadequately motivated antisocial behaviour.
  • Failure to learn by experience.
  • Ego centricity and incapacity for love.
  • Lack of affect.
  • Lack of self reflection.
  • Unresponsiveness in interpersonal relations.
  • Suicide threats not carried out.
  • Impersonal sex life, trivial.
  • Failure to follow any life plan.

Development of Psychopathy

  • 1952: DSM – Antisocial reaction/Psychopathic personality with asocial and amoral trends.
  • 1985: Psychopathy Checklist (Hare – based on Canadian forensic populations).
  • 1991: Psychopathy Checklist Revised (PCL-R) – considered “gold standard” of diagnostic tool.
  • Now considered a dimensional rather than categorical construct.

Two-Factor Model of Psychopathy (Lykken, 1948)

  • Primary Psychopathy:
    • Absence of social interaction.
  • Secondary Psychopathy:
    • Presence of antisocial or delinquent psychoses and neuroses.

Primary Psychopathy (PP)

  • Personality and affective aspects:
    • Pathological lying.
    • Manipulation.
    • Lack of remorse.
    • Premeditated behaviour.
    • Callousness.

Secondary Psychopathy (SP)

  • Lifestyle and behavioral features:
    • Parasitic lifestyle.
    • Impulsiveness.
    • Reactively violent.
    • Antisocial behavior.

Adaptation

  • A trait that has a fitness-maximizing consequence.
  • Complex and well-organized.

What is not an adaptation?

  • Genetic drift.
  • By-product.
  • Random.
  • Vestigial trait.

Human Evolution

  • Hominin: Humans, extinct human species & ancestors.
  • Hominids: Great apes. *Why a big brain?
    • Thinking.
    • Speaking.
    • Memory.
    • Language.
    • Learning.
    • Feelings.
    • Vision.
    • Balance.
    • Coordination.

Evidence for the 2-Factor Model (Primary Psychopathy)

  • Inability to discriminate between pleasant and unpleasant sounds.
  • Poor perceptual processing of distracting stimuli – goal focused.
  • Reduced attention to emotion cues and ability to change mood.
  • Positive response to negative stimuli.

Hominin Evolution

  • Timeline of hominin evolution, including species like:
    • Homo sapiens.
    • Homo neanderthalensis.
    • Homo erectus.
    • Australopithecus afarensis ("Lucy").

Distinguishing Hominins (Homo) from Hominids

  • Bipedal locomotion.
  • Different diet.

Early Hominids

  • Australopithecus afarensis:
    • Shares traits with chimps.
    • Small canines & bipedal.
  • Homo habilis:
    • Stone tools.
    • Larger brain than Australopithecus.
    • Use of tools reflect abstract thought.
  • Homo erectus:
    • Migrated into Eurasia.
    • Increased brain size – “encephalisation”.
    • Acheulean technology stone tool technology.
  • Homo heidelbergensis:
    • Ancestor to anatomically modern humans and Neanderthals.
    • Bigger brain (frontal and parietal lobes).
  • Homo neanderthalensis:
    • Complex stone & bone tools.
    • Evidence of symbolism.
    • Art.

Homo Sapiens

  • Anatomically modern homo sapiens
    • Differences from Denisovans & Neanderthals:
      • No occipital bun.
      • High forehead.
      • Smaller teeth and jaws.

What separates Homo sapiens from other hominins?

  • History of symbolism: beginnings shell beads from Blombos caves in South Africa, 77-100 thousand years ago (engraved pigment, up to 100 kya) Ostrich shell engravings, 60 kya, also South • Status symbols? Time and effort Africa • Using ochre as body paint – alteration of the self to make an impression – signal enhancement

Significance of Symbolism

  • A “diagnostic trait” of humans; “self- domestication” – watershed moment in human history

Language & Symbolism

  • Impossible without language (external symbolic storage)
  • Is beyond behavioural information

Social Intelligence Hypothesis

  • (Chance & Mead, 1953; Jolly, 1966; Humphrey, 1976)
  • Selective pressures caused by the social environment - competition & cooperation with conspecifics important factor in the evolution and shaping of the brain and cognition in animals

Social Brain Hypothesis

  • (Barton & Dunbar, 1997)
  • Correlation between relative brain size (neocortex) and social group size
  • Predation is related to group size
  • Social cohesion needed to avoid predation

Dunbar’s Number

  • Social brain hypothesis – calculation that humans have cognitive capacity/constraint for meaningful information held of 150 individuals

Birth of Evolutionary Psychology

  • Charles Darwin – “The Descent of Man, and Selection in Relation to Sex” (1871)
  • Still relatively young subject field – early 1990s

Tooby & Cosmides (1992) – Theoretical Background

  • Rooted in cognitive psychology – Information processing approach
  • Integrated Causal Model:

What is a Psychological Adaptation?

  • Purpose of adaptative psychological mechanisms to be found through ”reverse engineering” – engineered problem-solving mechanism

How are Psychological Adaptations Designed?

  • In the EEA – the following were reliable features of humans and human behaviour
    • Emotions and emotional communication
    • Humans interact in a mutually beneficial way with non-relatives

Different Aspects of Evolutionary Psychology

  • Personality
  • Altruism & kin selection
  • Parental investment theory & parenting
  • Mate choice
  • Language

Personality as an Adaptation

  • Personality is a psychological adaptation to operating within a highly social environment – device for communication (not genetic noise or by-products other adaptations)

Altruism & Kin-Selection

  • Altruism poses a problem because it increases the fitness of another individual at your expense

Parenting: Parental Investment Theory

  • The level of consideration given to a potential mate is a function how much energy is expended in childcare

Parenting in Humans

  • We are unique in that we have a very long period of development

Trivers-Willard Effect (1973)

  • How a mother apportions energy/resources to children depending on the quality of the environment
  • Mothers in poor condition will have a preference for female offspring
  • Mothers in good condition are able to invest in male offspring

Mate-Choice

  • Intrasexual (competition between males)
  • Intersexual (females choose their fellas)
  • Fisher’s runaway selection (1930) – A physical trait becomes more extreme because it is reliably selected for by females (e.g., Peacock’s feathers)

Controversies in EP

  • “Just-so stories”:
  • Genetic determinism
  • Theoretical Criticisms of EP

Evidence for the 2-Factor Model (Secondary Psychopathy)

  • Higher levels of anxiety, depression and suicidal ideation (Vaughn et al., 2009)
  • Negative urgency – act impulsively to relieve currently experienced negative emotions (Anestis et al., 2009)

Response Modulation Theory (Newman & colleagues)

  • Attentional processing deficit – can’t attend to peripheral information that presents threat and distress cues (or insufficient allocation of attentional resources)
  • Higher order cognitive processes mediate neural functioning

Low-Fear Model of Psychopathy (Blair, 2005; 2006)

  • Deficient amygdala, paralimbic system, & orbito-frontal cortex (neural regions associated with fear and emotion processing)

Neurobiological Characteristics of SP

  • Deteriorated prefrontal cortex grey matter – bad decision making (Raine et al., 2000)

How Does Psychopathy Develop?

  • Callous-unemotional (CU) traits (in children)
  • Emerge from 2-years old
  • Under strong genetic influence from 7-16 years (estimates of 40-78% heritability)

Nature and Nurture

  • CU traits may even protect against adverse rearing environment
  • Antisocial behaviour (ASB) is moderately influenced by genetics as well as shared and non-shared environmental factors

“Successful” Psychopathy

  • Psychopaths are charming, lack of anxiety, and articulate, but also guiltless, callous and self centered (Lilienfeld et al., 2015) – happy to deceive people

Models of Successful Psychopathy

  • Differential severity model
  • Fearless dominance:

How Narcissism is Different to Psychopathy

  • Psychopathic individuals can be narcissistic
  • But narcissists are not necessarily psychopathic

Psychopathy as an Evolutionary Adaptation?

  • “Male-typical”, cheater strategy
  • Resources and mates through cheating
  • Short-term relationships, risky sexual behaviour, unrestricted sociosexuality, casual sex, exploitative, and aggressive mating tactics

Primacy Psychopathy as an Adaptation

  • Psychopathy as an adaptation to altruistic social groups during Environment of Evolutionary Adaptedness (exploit trust)

SP as an Adaptation

  • Developmental plasticity
  • Environmental conditions can change temporally and spatially

Sex Similarities in Psychopathy

  • Primary psychopathy
    • Fear and emotion processing deficits
  • Secondary psychopathy
    • Same adverse emotional style

Sex Differences in Psychopathy

  • Women:
    • Less likely to engage in either proactive or reactive violence – will use indirect or relational aggression instead

How to Diagnose Psychopathy

  • Psychopathy Checklist Revised (PCL-R)- 20 items scored (0, 1, or 2) http://www.hare.org/
  • Collateral and interview information used to score personality traits and behaviour
  • Score of >25 is concerning, >30 = psychopathy. Av score in general population is 5

Issues over Assessment

  • Reliability of inter-rater scoring (e.g., Edens et al., 2010)
  • Which side the assessor is on in criminal case

Psychopathy and Treatment

  • We still don’t fully “know” what psychopathy is
  • Not a single disorder but actually a “dimensional configuration of traits” (Polaschek & Daly, 2013)

Background to Controversy with Psychopathy Treatment

  • Typically considered unlikely (Cleckley, 1941)

Psychopathy and Crime

  • Key predictor in violent offending. Factor 2 is more predictive (unstable antisocial lifestyle) than Factor 1 (Affective and Interpersonal) (Leistico et al., 2008; Coid et al., 2008)

Psychopathy and Sexual Offending

  • Olver & Wong (2006) studied psychopathy and recidivism in a sample of federally incarcerated sex offenders (incl. 10-year follow-up).

Psychopathy and Criminal Responsibility

  • Are psychopaths fully criminally responsible for their actions?