Developmental & evolutionary psychology

How has developmental psychology shaped parenting over the past 100 years?

• Founded in Watson’s behaviourist critique to motherhood, warning the dangers of excessive love & affection

• ‘Psychological Care of Infant and Child’ (1928) parenting book, the threat of mother love
  

PUSHBACK:

• Rene Spitz (showed mother-child bond is important for social development, otherwise causes psychogenic disease)

• John Bowlby (WHO report: importance of early-life connections)

• Benjamin Spock (‘trust yourself’ parenting, common sense approach)

+

• Harrow Harlow (primate experiments showed babies preference for comfort, evidence for ‘love’, not a clear observable outcome)

NOW → the age of maternal anxiety

• Relearning basic biological instincts

• Popular media: how’s everything ruining ur child’s development?

• Motherhood is NOW important, so we study every wrong method

Biases in interpretation of development research

• Animal research in developmental psychology is not objective, and compounded by many unaccounted for variables

• Thoughts & feelings (the why) are not explicitly expressed, so we have to infer

• Research data is often phrased/biased to fit a story we want to tell

• Vastly manipulated for interest, fixates on the ‘bad’ or controversial elements, is oversimplified

Animal models to study early life development

Maternal separation: remove baby rats once a day for first 12 days of life

• Significantly distresses mother, litter is only affected by consuming stress hormones via lactation

↓

Maternal corticosterone exposure: can also be induced through water

• Infantile amnesia is disrupted due to early stress exposure

• Causes adult-like fear and extinction learning

i.e., fear conditioning on P17 + extinction on P18 → contextual renewal still occurs

Animal models to study maternal behaviours

Note: in experiments, ‘good’ vs ‘bad’ maternal scare is scored by engagement (i.e., arched-back vs passive) for a median split

Limited bedding: example of early life stress

• Correlated with ‘abusive’ behaviour

• People stressed with limited resources give poor quality of care

• Consequently, roughly handled pups suffered adverse impacts to physiology + behaviour
  

HENCE: when judging parental behaviours, look at overall familial support

Major developmental milestones in motor behaviour

NOTE: mobility develops bidirectionally

1. Cephalo-caudally (head → feet)

2. Proximo-distally (centre/medial → outward/lateral)

Gross motor skills: large muscles of the body (crawling, walking, jumping)

1-4 months: reflexes, lifting head, sitting with support

5-9 months: INTENTIONAL rolling over, sitting without support

BY 10-11 months: pulling to standing, crawling

10-17 months: standing & walking alone

18-30 months: running & jumping

*the same behaviours or attempts at behaviours can present drastically differently between children

Fine motor skills: precise movements with small finger/hand muscles

2 months: holding objects briefly when handed

3-4 months: reaching, inspecting fingers, object towards mouth

4-5 months: holding 2 objects & moving hand-to-hand

5-6 months: bang objects together

6 months: reaching, grabbing, retaining objects + manipulating & examining

7-8 months: pulling string to obtain object, four finger grip (thumb + fingers)

8-10 months: gripping & releasing objects

10-12 months: pincer grip (thumb + forefinger), put 3+ objects in container

Major developmental milestones in perception

Vision

0-4 months: very underdeveloped because it doesn’t need to be

• Restricted mobility

• 15-25cm range of focus (distance of caregiver)

• Sensitive to high contrast (black, white, red)

5-8 months: gains depth perception (3D)

• Colour vision develops

• Useful for reaching to objects in environment

9-12 months: can now judge distance

• Feedback for navigating environment

• Develops along with improved mobility

Hearing

• Inner ear is fully developed by 3rd trimester

• Foetuses can respond to sounds, with a preference for mother’s voice

• Hearing (cochlear cell movement) is tested at birth using EOAE

• Newborns prefer organised sounds (music, rhythm) > disorganised sound

Major developmental milestones in cognition

Object permanence: achieved by end of sensorimotor period (~2 years)

• i.e., world can be represented by words & images > immediate sensory impressions/actions

• ‘Objects exist even when they can’t be observed’

• Develops along with motor capabilities

• Associated with early-age separation anxiety

• ‘A not B error’, when skill has just emerged → incomplete schema, perceiving where an object WAS, not where it IS

Egocentric thinking: presents until around age 7

• Children assume everyone’s sensory experience = theirs

• ‘The ability to see a situation from another person’s perspective’

• Difficulty communicating/conflict

• Referring to things only they see, using pronouns over names

When are interventions required to help children and parents?

Noting large variability: genuine delays in development can indicate genetic, neurological, muscular, developmental conditions etc.
→ benchmarks are a useful guide to flag potential concerns early

For language, consistent delays can suggest Autism, ADHD
→ note however, judging children’s ability to regulate attention in non-biologically selected settings contributes to overmedicating/overdiagnosis

Interventions + therapy help build skills and increase confidence

The large variability in ‘typical’ development + challenges with assessment

Overall, human babies are hard to study → our bipedal nature means we’re born comparatively very underdeveloped

• We can directly observe responses, but have to infer why

• Experiment designs need to be creative

• i.e., Pavlovian conditioning for a toddler hearing test
  

Factors influencing development include:

• Environmental stimuli

• Interactions with parents, siblings, carers

• Drive and motivation

• PERSONALITY

Major developmental milestones in language

Reflects imaginative capacity & facilitates interactions with the world

Expressive language: communication efforts made by child

• Verbal & nonverbal

• Early: eye contact when spoken too, crying, babbling, cooing, smiling

• Late: imitating/minimal speech, gestures, phrases

Receptive language: how much they understand

• Evidence of reception of others’ communication attempts

• Early: awareness of speaker, watching mouth/eyes, following direction of sound, listening/responding

• Late: following directions, pointing, head shake/nod

Empathy

A SHARED, AFFECTIVE STATE → prosocial, altruistic

• A sharing of another’s feelings, genuine state or condition VERY similar to the other person

• Includes a rection to observed distress i.e., approaching, “Can I help?'“

Sympathy

An affective response unique to the individual, like feeling sorrow or concern for another’s misfortune, to seeing them in distress

Personal distress

A SHARED, AFFECTIVE STATE → self-focused, alleviating own discomfort

• A self-focused, aversive response to another’s condition

• Includes a reaction to observed distress i.e., aversion in response to discomfort, anxiety

How, when and why does empathy develop

Romanes’ mental hierarchy: the progression of mental complexity

WHY:

• Only highly social species can develop sympathy which is crucial for living collaboratively in communities

• Sensitivity to others’ thoughts and feelings is required for societal regulation, inherent in our perception of moral right or wrong

WHEN:

• Mothers’ faces attract attention from ~1 month

• Awareness of social cues and facial expressions shows as infant responses by 3 months

HOW:

• Early ‘conversation’ as contingent maternal responses to infant signals

• Critical early developmental skills like communication and reading faces are formed very early in these ‘conversations’ between caregiver and infant

Why is social learning uniquely important for humans?

Humans more than any other species need companionship
→ beyond food & protection, informs self-regulation, management, communication skills

A failure of contingent maternal responding to infant signals due to deliberate perturbation or maternal depression has DISRUPTIVE and DISORGANSING effects on infants under 3 months

• i.e., postpartum depression puts children at heightened risk for emotional problems up until adolescence

• Attachment to early caregivers informs attachments later in life, teaches us to connect

• Poor mother-infant interactions creates poor attachments & emotional resilience

• Maternal sensitivity = greater security

• Maternal intrusiveness/remoteness = greater insecurity

‘Normal’ empathy development

[~3 months] noticing and reacting to others’ distressed expressions

[10-12 months]

• ‘Watching’ but unresponsive to distress, emotions are interesting

• Learning, not responding (~50% time some frown, look sad, cry)

[12-24 months] = egocentric empathy

• Less personal distress, more active interventions

• Self-other distinction, empathetic responses are measurable

• Overlooks individual inner states & language of description

• ~18mo brings distressed person objects, seeks help, protects

[3 years] = empathy for others’ feelings

• Others’ feelings differ from their own (but individual differences)

• Taking active steps of alleviating others’ discomfort

• Responds to distress regardless of role in creating it

[>5 years] = empathy for others’ general plight

• Emergent idea of others’ life experiences, histories, identifies

• Others’ life conditions inform actions

Studying empathy in young children

TEST:

1. Affective response

2. Behavioural response

In scenarios with encoded responses → social cues/info inform responses

• Differentiate empathy vs sympathy vs personal distress

• Measure scale of responses

Personal distress & empathy studies on children

1. Does the extent of physiological arousal influence responding? (Eisenberg, Fabes et. al., 1990, 1996, 1998)

   • Assume continuity between physiological measures (HR/skin conductance) & observational data

   • Well-modulated arousal: regulated empathy response
     → balanced physiological arousal, not overwhelmed or distressed i.e., good sportsmanship

   • Poorly-modulated ‘over’ arousal: excessive emotional response to distress, too reactive

     → leads to discomfort, anxiety, aversion

2. Passive paradigm experiments [can view but cannot act]
   (Fink, 2011)

   • Kindergarten children watch emotionally evocative events, grouped by types of affective empathy response → inexpressive, concern, sad

   • Worry-concern group tapered off midway suggesting disengagement and avoidant tendencies = more poorly-modulated, over aroused, socially immature)

How does empathy influence the development of the ‘theory of mind’?

AKA cognitive empathy: understanding the WHY of another’s mental state without feeling yourself (absence of emotional input)
→ can children comprehend distress without seeing something distressing

• Hostile condition: person’s possessions are destroyed

• Neutral condition: other non-personal objects are destroyed

Both conditions play with balloons and individual loses theirs:

Neutral = reasonably high empathy

Hostile = prosocial behaviour (balloon sharing) even more likely

Overall: showed facial signs of concern/sadness, none ignored

NOTE: capacity to hurt others develops along with comfort (both linked to overall socio-cognitive understanding and regulation)

Empathy failures

Callous-unemotional (CU) = PERSONALITY TRAITS

• Lack of empathy, guilt, remorse, shallow affect

• Increases risk of antisocial behaviour, poor punishment response

• ‘Cognitive empathy’ can remain intact

• Combination associated w/ psychopathy (or conduct disorders)

Antisocial behaviours (AB) = ACTIONS

• Violating social norms, ignores others’ rights, harm-causing, rule-breaking, lying, aggression, theft

• Exclusively impulsive, poor emotional regulation, environmental

• Risk factor for psychopathy

AB + CU = heritable, low arousal to distress, AB caused by poor punishment response/affective empathy

Only AB = environmental, high arousal to distress, behaviours are reactive to perceived/imaged threat

‘Normal development’

• Milestones labelled by age ranges (but note late vs absent)

• Measured on normal distribution by standard deviations

• Historical deficit approach to abnormal psychology but now requires multidimensional approach

• Development isn’t always predictable or linear

NOTE: ‘abnormal’ psychology includes giftedness (top 2% IQ)
→ high dropout rate, difficulty fitting in, poor catering for needs, frustration, disruptive, isolated, lonely,

Application of developmental psychology for language delays

1. Expressive language impairments (easy to diagnose)

   • Difficulty with words/sentences, expressing ideas

   • Reduced vocab, grammatical errors, cannot converse

   • Difficulties in written expression

TREATMENT: early identification (higher neuroplasticity), speech pathology, classroom assistance, special education

CAUSES: down syndrome, ASD, ADHD, head trauma

2. Receptive language impairments (comprehension)

   • Understanding meaning or what is said

   • Inappropriate responses, can’t follow instructions/listen

   • Disinterest in literacy, falling behind academically

TREATMENT: early identification, speech pathology, increase home use of language, psychological treatment (for behavioural/cognitive problems)

CAUSES: global developmental delay, poor language exposure, attention disorders, hearing impairments (and chronic infections), visual impairments

2 types of language processing

Analytic = neurotypical language acquisition

• Part to whole, processes words first

• Learning words referentially (association & relation)

Gestalt = neurodivergent, phrases & chunks > individual words

• Whole to part, processes intonation first

• Learning language through experiences

• Indicated by contextually inappropriate language use

1. Delayed echolalia (repeating chunks from people/media/books)

2. Mix & match stage (combining chunks or making smaller ones)

3. Single words/2-word combos (one-word units, new combos)

4. New original phrases & sentences (novel phrases and sentences, progressing to complex grammar)

Technology in developmental psychology research (current)

Generally: allow video chatting, adult moderation of content, limit at mealtimes and 1hr before bed → calling vs learning vs entertainment

Problems:

1. Sleep inhibition causes problems and delays

2. Sedentary behaviour is habit forming, obesity concerns

3. Toddlers’ time should be maximized for learning/skills

Predictors = poor maternal mental health, mother viewing TV time, family dysfunction/stress, ADHD or ASD

Neurodivergence in developmental psychology research (current)

Increasing diagnoses due to:

• Improving and specific diagnostic criteria (M vs F presentation)

• Understanding of individual differences across development

• Increasingly narrow definition of ‘normal’

• Knowledge of comorbidities, neurodivergence as a causality

Useful for meeting neurodivergent children’s’ needs to reduce distress and improve educational outcomes (moving away from punishment)

Why is adolescence a unique developmental period

Infancy to juvenility → first neurogenesis (amnesia) to concrete memories and high resilience (plasticity and synaptic formation)

Adolescence = unique period of high synaptic pruning

• Significant development in cognition (abstract thinking, problem-solving, emotional regulation)

• High risk-taking behaviour as prefrontal-cortex develops

• Total brain volume peaks in adolescence

• Starting age 10, grey matter vol. decreases (dendritic spines) + white matter vol. increases (strengthening useful circuits)

Key hallmarks of adolescent neurodevelopment

• Cognitive development

• Increased social behaviour

• Increased risk taking (impermanent reduction of fear + threat pessimism, crucial for motivation to be independent)

• Emotional intensity (dysregulated cognitive control)

Adolescent vulnerability to mental health conditions

Environmental stress can increase synaptic pruning + existing genetic vulnerabilities = insufficient circuity for function

• Loss of up to 50% of prefrontal cortex synapses (poor cognitive control and emotional regulation)

• Rise in substance abuse due to emotional intensity + more vulnerable to dependence due to brain changes

• Early peak in anxiety disorders, late peak in schizophrenia (mood disorders diagnosed much later)

• Prefrontal cortex develops later than amygdala (emotional processing) means high emotional reactivity drives responses

  → overall poor vmPFC-amygdala interactions except in anxious adolescents

TREATMENT: very limited for anxiety & mood disorders
→ CBT has higher relapse rates (poor fear extinction), SSRIs increase suicidal ideation, unknown impacts on developing brains

How can animal models be used to study ‘typical’ and ‘atypical’ adolescent development

1. Adolescent cocaine-induced habits

   → adolescent rats exposed to cocaine preferred habit-behaviours over goal-directed & fewer dendritic spines in PFC
   → poor decision-making, cocaine disorganizes synaptic pruning

2. Adolescent responses to stress

   → adolescent mice given corticosterone were more sensitive to acute stressor (cage change) & fewer dendritic spines
   → elevated/chronic stress hormone exacerbate stress responses, poorer processing & management

3. Anxiety disorders using fear extinction

   → for modelling exposure therapy using Pavlovian conditioning
   → adolescents can’t maintain fear extinction
   → children show less initial fear response

Prefrontal cortex & amygdala imbalance

PFC = higher-level cognition, impulse control, executive function

• Prelimbic (PrL): fear response expression, decision-making

• Infralimbic (IL): extinction learning, fear response suppression

  → fewer IL markers for synaptic plasticity in adolescents = more risk-taking and impulsive behaviours

Amygdala = immediate emotional responses

• Basolateral amygdala (BLA): learning and strong associations

• Central nucleus (CeA): fear expression

Juveniles = ↑ BLA (good extinction), ↓ CeA (less fear response)

Adolescents = ↓ BLA (bad extinction), ↑ CeA (high emotional reactivity)

Adults: ↑ BLA (good extinction), ↑ CeA (but response is regulated)

Tinbergen’s 4 questions about behavioural causes

1. The mechanism or causation?
   (is it inherent? neurobiological?)

2. What’s its adaptive value?
   (function/utility, enhance survival/reproduction? what’s the future goal following the behaviour?)

3. How does it occur throughout development?
   (ontogeny, life experiences causing the behaviour’s omission)

4. How did it evolve across a species?
   (phylogeny, from ancestors leading to an instinct/predisposition to acquisition)

*evolutionary psychology looks at adaptive value and phylogeny

Example of Tinbergen’s 4 behavioural causes in children

Mechanism: stimulus triggers prosocial response, neurobiologically wired to process stimuli → make decision → act

Ontogeny: helpful behaviour emerges early, expression is shaped + reinforced by adults

Adaptive value: strengthens bonds, fosters protection and social inclusion

Phylogeny: seen in closely related species and other social mammals

Darwin's theory of evolution by natural selection

• The change in organisms traits across generations is due to natural selection

• Over time, causes evolution across a species, better adapting to its environmental niche

• Homologous behaviours are shared by related species, can be species specific, run in families (Linnaean taxonomy)

Fitness in evolutionary theory

Reproductive success, relative to direct competitors to the population

1. Limited resources causes competition

2. Individuals best suited to the environment survive and reproduce

3. These advantageous characteristics are passed onto their offspring via inheritance

3 requirements of evolution by natural selection

1. Variation must be present within a species (due to mutation)

2. Selection pressures meaning some individuals are naturally better equipped for survival in the environment, living longer, and produce more offspring

3. Trait heritability determined by the number of offspring, and the favourability of the mutation

Evidence for evolution of mental abilities

1. Comparative psychology & neuroanatomy

   • All mammals have similarly structured brains and functional units, with differences in scale

   • Certain behaviours are similarly expressed in closely related species

2. Behaviours affect fitness

   • Species-specific defensive responses (SSDRs) in the desert vs woodland deer mice

   • Mice demonstrated an innate ability to recognise their specific environmental predator

   • Presence of defensive behaviours in some

3. Artificial selection of mental abilities

   • Breeding of ‘bright’ vs ‘dull’ rats in maze solving generated cognitive phenotypes

   • Cognitive traits can be modified over time, via natural or artificial selection

4 types of fitness exchange between animals

1. Mutualism/reciprocity = benefits initiator & recipient

2. Selfishness = benefits initiator, costs recipient

3. Altruism = costs initiator, benefits recipient

4. Spite = costs initiator & recipient

Altruism

The selfless act of helping others, motivated by a concern for their wellbeing without expecting personal gain or reward

• Instinctive, and according to Darwin should remove themselves from the gene pool

• Reduces fitness of altruistic individuals, increases fitness of everyone else they help

Inclusive fitness

Indirect reproductive success achieved by helping relatives with similar genes

→ Altruistic individuals are more likely to help relatives, who are then more likely to survive and reproduce, indirectly helping to pass on their own genes.

• Success is the beneficially of the trait itself, not defined by individual fitness

• Altruistic individuals increase the fitness of any individuals in the next generation with that trait

How does kin selection solve the problem of altruism?

Individuals with altruistic traits will sacrifice their chances of reproduction if it will increase the chance of relatives reproducing

• Individual success = reproduction of genetic kin

• Relatedness is positively correlated with the likelihood of sharing an altruistic gene

• Act is costly to initiator, but the trait is advantageous if the recipient is related

• Shows importance of parental investment, material support from aunts and uncles, grandparent effect increasing a child’s fitness, and non-breeding relatives

Most effective when size of benefit x relatedness > cost to initiator
= net gain in fitness of altruistic trait across population

How does reciprocity solve the problem of altruism?

Short-term → altruistic

Long-term (if reciprocated) → mutual benefit

• Seen a lot in primates and maintained in competitive environments

Conditions for reciprocal altruism

• Propinquity (increased chances of meaningful interactions)

• Slow discounting of delayed rewards (more common in humans & primates, can forgo immediate gratification)

• Low cost for high benefit (value = material itself + context of what you already have)

• Self regulating (to maintain cooperative groups)

  • Detecting & punishing cheating (improves overall contributions to common good)

  • Instinct for fairness (innate strong emotional response to injustice)

Social theory of intelligence

Humans can solve the Watson Selection Task (‘cheating problem’) much faster if presented in terms of societal laws and constructs

• Cohesive social groups provide advantage to fitness

• Demands of complex social environments drove the evolution of problem-solving to maintain functioning, cooperative society

• i.e., remembering interpersonal interactions, hierarchical power, relationships, deception, planning, arguing

Humans demonstrate prosocial behaviour when not reciprocated because it signals trustworthiness
→ increases likelihood of cooperation, increases status & reputation, protection social norms benefits society

How do genetic backgrounds and one's environment interact?

Instinct = urge and a competence, ability to behave that way, preparedness
+
Experiences = opportunities, appropriateness, shapes expression, enculturation, social norms

Behavioural neuroscience → across basic tests, genetically similar lab rats treated the same way showed differences in testing environments

Epigenetics → gene expression of grasshoppers changes to locusts in high density, low food environments causing a different phenotype and behavioural patterns

Cognitive development → restricted environments were detrimental to bright rats, enriched environments were beneficial to dull rats

Instinctive behaviour?

Innate, fixed action patterns performed in response to sign stimuli
→ ethology describes these innate actions as the result of natural selection acting on behaviour

• Has physiological and neurological mechanisms

• Innate, but have a trajectory, modified by experience and develop through ontogeny

• Behaviour is innate to a species (phylogeny), shaped by natural selection

• Has an adaptive value, contributing to reproductive success

How do innate processes and learning interact?

Learning is not always gradual, nor flexible. Some learned behaviours depend on innate timing mechanisms, and specific environmental input

1. Sensitive periods: learning predisposition often has a critical period due to increase neuroplasticity i.e., language learning for children

2. Preparedness: organisms are biologically predisposed to learn some things easier than others, preferential association i.e., phylogenetically relevant stimuli, phobias of ancestral threats condition more easily and resist extinction

Instinctive drift & instrumental learning in the context of species-specific defensive responses (SSDRs) and avoidance learning

Behaviours learned through operant conditioning are easily disrupted or replaced by innate, instinctive behaviours

• Threat perception automatically triggers SSDRs

• Avoidance learning is easiest when the required behaviour matches natural defensive responses (rapid learning)

• Animals select pre-existing behaviours, not just learn new ones

• i.e., easier to pair warning signal + shock on same side of room → run away from danger

Instinctive drift & instrumental learning in the context of ‘Misbehaviour’ and appetitive learning

Behaviours learned through operant conditioning are easily disrupted or replaced by innate, instinctive behaviours

• In instrumental training, appropriate reinforcers can be selected to elicit the best behaviour

• i.e., rewarding dogs with instinctive behaviours (fetching ball) to reinforce the previous hunting behaviour (seek)

• Misbehaviour can occur if operant conditioning conflicts with an animal’s natural instincts

Fixed action patterns and sign stimuli

Sign stimuli are environmental cues triggering a FAP:

A behaviour omitted by an animal, unique to that species, and NOT learned
→ once it arises, follows a specific trajectory of performance in a pre-programmed sequence running all the way through
→ in fully-formed animals

Tinbergen’s hierarchical model of instinctive behaviour

Instinctive behaviour is organized around general motivational drives which build in impulse
→ behavioural impulses are triggered by innately releasing mechanisms → triggers cascade effect to specific action patterns when motivation reaches a threshold, inhibiting competing behaviours
→ fixed action patterns in response to external stimuli

1. Defensive
   a. Freeze
   b. Flight

2. Reproductive
   a. Fighting

   i. Chasing
   ii. Biting
   iii. Threat
   [nesting]
   c. Mating
   i. Dancing
   ii. Leading female to nest
   iii. Fertilising eggs