Evolutionary Psych-Class 18

physical abuse

deliberate harm such as hitting or burning

emotional abuse

rejection, isolation, and denigration

abuse rates around the globe?

vary, influenced by cultural norms

child neglect

the persistent failure to meet a child’s basic needs

• often more common and chronic than active abuse

• cultural standards influence what is considered neglectful

neglect can include?

physical, emotional, educational, and medical

ifanticide

the killing of infants, often linked to resource scarcity

culture and infanticide

• historically practised in many cultures under specific conditions

• female infanticide more prevalent in patriarchal societies

  • modern laws universally criminalise it, but is persists covertly

cross-cultural childhood maltreatment

• What constitutes maltreatment can differ across cultures.

• Some societies view corporal punishment as discipline.

• Indigenous and minority children may be overrepresented in child protection systems.

• Cultural competence is essential in evaluating child welfare cases.

global prevalence of child maltreatment

• WHO estimates 1 in 4 adults report physical abuse in childhood.

• 1 in 5 women and 1 in 13 men report sexual abuse as children.

• Emotional abuse and neglect often go underreported.

• Global prevalence varies significantly by region and reporting standards.

child deaths and severe outcomes

• Globally, up to 50,000 children die annually due to homicide.

• Infants under 1 year are at highest risk of fatal abuse.

• Most fatal cases involve a caregiver or known individual.

• Long-term outcomes include increased risk of mental illness, substance use, and suicide.

child abuse in Canada

• In 2019, 1 in 3 Canadian adults reported experiencing childhood maltreatment.

• Physical abuse (27%) and exposure to intimate partner violence (17%) are most common.

• Indigenous children are disproportionately affected by all forms of maltreatment.

• Child welfare systems are often overburdened and under-resourced.

evolutionary lens on trauma

• Childhood trauma is viewed as an evolved response to environmental conditions.

• Adverse experiences may trigger adaptive survival mechanisms.

• Trauma-related traits can persist due to ancestral utility.

• The evolutionary lens explains both vulnerability and resilience.

stress as a signal

Stressful early environments signal unpredictability and danger.

• These signals can accelerate development and reproduction.

• Trade-off: short-term survival vs. long-term mental health.

• Evolution shapes development to match expected future conditions.

attatchment systems

• Human infants evolved to attach to caregivers for survival.

• Disrupted attachment from trauma affects social cognition.

• Insecure attachment styles may have adaptive value in high-risk settings.

• These adaptations can become maladaptive in safe environments.

hypervigilance as adaptation

• Hypervigilance helps detect threats in dangerous environments.

• Traumatized children may appear anxious or overreactive.

• This trait increases immediate survival chances.

• However, it raises long-term risks for anxiety and PTSD.

recalibration of brain systems

• Trauma can recalibrate the HPA axis (stress response system).

• Childhood adversity may ‘program’ sensitivity to stress.

• This is an adaptive trade-off: heightened alertness vs. chronic arousal.

• Brain plasticity allows this flexibility during development.

life history trauma

• Adverse environments promote “fast” life history strategies.

• Includes early reproduction and risk-taking behaviours.

• Prioritizes survival and reproduction over long-term planning.

• Childhood trauma may trigger these shifts as a fitness strategy.

social learning and trauma

• Children model behaviours observed in their environments.

• Abusive or neglectful caregiving can become learned norms.

• Evolution supports learning from caregivers—even when harmful.

• This mechanism preserves social cohesion at the expense of mental health.

mismatch with modern environments

• Evolved responses may be ill-suited to modern life.

• For example, hyperarousal in safe school settings can impair learning.

• Evolutionary mismatch theory explains this disconnect.

• Trauma-related behaviours may clash with institutional expectations.

intergenerational trauma

• Trauma can be passed across generations through parenting.

• Epigenetic changes may underlie some intergenerational effects.

• Evolutionarily, this may prepare offspring for harsh conditions.

• This perpetuates trauma in disadvantaged communities

role of culture

• Cultural context influences how trauma is processed and expressed.

• Collectivist societies may buffer effects through strong social networks.

• In individualist cultures, trauma may lead to isolation.

• Evolutionary mechanisms are shaped by socioecological context.

risk detection systems

• Children evolve to detect social threats and status hierarchies.

• Maltreatment sharpens these detection systems.

• Overactivation leads to paranoia or mistrust in adulthood.

• These outcomes reflect calibrated adaptations to early conditions.

moral emotions and trauma

• Guilt, shame, and disgust help regulate behaviour.

• In trauma, these emotions can become distorted or hyperactive.

• They may have evolved to promote group cohesion.

• Dysfunctional expression may underlie disorders like depression or OCD.

gender differences

• Girls and boys may exhibit different trauma responses.

• Evolutionary roles may influence internalizing vs. externalizing behaviours.

• Females tend to develop depression and anxiety; males show conduct issues.

• These patterns may reflect evolved survival strategies

suicide as adaptive signal

• Some theorists argue suicidal behaviour may serve social functions.

• May communicate distress, elicit help, or reduce burden.

• Evolutionary view sees suicide as misfiring of adaptive mechanisms.

• Does not imply endorsement but encourages deeper understanding.

dissociation and trauma

• Dissociation may have evolved to reduce suffering during trauma.

• Enables psychological escape when physical escape isn’t possible.

• Chronic dissociation disrupts identity and memory.

• This mechanism, once protective, can become disabling

play and socialization disruption

• Play is essential for social and cognitive development.

• Trauma can suppress play behaviour due to perceived threat.

• Reduced play impairs empathy, cooperation, and resilience.

• Evolution prioritizes threat response over exploration in danger.

symbolic thinking and meaning-making

• Humans evolved to create narratives and assign meaning.

• Traumatized individuals often grapple with distorted beliefs.

• These beliefs can be adaptive stories in threatening worlds.

• Therapy may involve revising these internal evolutionary narratives.

developmental windows

Sensitive periods in development make children especially vulnerable.

• Evolution optimises development for timing and plasticity.

• Trauma during these windows alters long-term trajectories.

• This supports early intervention and prevention efforts.

trauma and altrusim

• Some trauma survivors develop heightened empathy and care.

• Evolution may support increased social bonding in adversity.

• Not all trauma leads to dysfunction; some fosters prosocial traits.

• This reflects the diversity of adaptive responses.

implications for psych care

• Understanding trauma evolutionarily can reduce stigma.

• Symptoms can be reframed as contextually adaptive.

• Psychological support should address both biology and environment.

• Evolutionary perspectives enrich trauma-informed care models.