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EARLY CHILD DEVELOPMENT: MYTHS & SUBSTANCE. By Michael Rutter. 448. MYTH - I. It is only in the preschool years that environmental influences can have a lasting biological impact because it is only then that rapid brain growth occurs Wrong because

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myth i
MYTH - I
  • It is only in the preschool years that environmental influences can have a lasting biological impact because it is only then that rapid brain growth occurs

Wrong because

i. brain growth continues into early adult life

ii. experiences later in life have been shown to have neural effects

pattern of brain development
PATTERN OF BRAIN DEVELOPMENT
  • Evidence from post-mortem studies (Huttonlocher)
  • From longitudinal brain imaging studies (Giedd et al.)
  • Findings:

i. Initial overproduction of neurons & synapses followed by selective pruning of non- functional connections ('use it or lose it')

ii. This process occurs in early childhood but also in adolescence

iii. The timing varies in different parts of the brain

iv. Considerable individual differences in timing

slide4

Right lateral and top views of the dynamic sequence of GM maturation over the cortical surface

Gogtay N et al. PNAS 2004;101:8174-8179

©2004 by National Academy of Sciences

effects of adult experiences on neural structure
EFFECTS OF ADULT EXPERIENCES ON NEURAL STRUCTURE

e.g.

  • London taxi drivers & size of the posterior hippocampus
  • Neural correlates of violin playing
  • Longitudinal neural effects of learning juggling skills
slide6

Volumetric analysis findings

Maguire E A et al. PNAS 2000;97:4398-4403

©2000 by The National Academy of Sciences

myth ii
MYTH - II

There is only one sort of biological effect

Wrong because there are at least 3 different varieties

i. Experience-expectant effects

(cf Hubel & Weisel expts on binocular vision & development of the visual cortex)

Termed 'expectant' because in all ordinary circumstances the necessary experiences will always be available

ii. Experience-adaptive effects

(cf Barker hypothesis re long-term effects of restrictions in early growth)

Unlike experience-expectant effects, these concern variations within, as well as outside, the normal range. Termed ‘adaptive’ because the body is adapting to the nature of early experience

iii. Experience-dependent effects

(cf the adult experience examples)

Unlike the first two varieties, these are not restricted to any kind of sensitive period restrictions

myth iii
MYTH-III
  • If there is a neural effect, this will necessarily lead to a permanent change in function. Conversely, if there is no neural effect, there can be no permanent change in function

Wrong because

    • Many examples of recovery following definite brain injury

(cf. eg follow-up of children with cerebral palsy, and lack of aphasic features following lateralised brain injury in early childhood)

    • Epigenetic effects that are not a function of neuronal growth/pruning

(cf. Meaney’s studies in rats of archback nursing in infancy)

    • Lasting effects of physical stress on neuro-endocrine structure & function

(cf. Levine’s studies in the 1960s)

myth iv
MYTH-IV
  • Environmental effects on the brain during critical periods of growth are universal and invariant

Wrong because

    • Good evidence of genetic influences on environmental vulnerability
    • Apparently similar experiences may lead to either ‘steeling’ (ie protective) or ‘sensitisation’ (re vulnerability) effects
    • Some evidence of effects of both social context and prior experiences
slide11

EFFECT OF MALTREATMENT IN CHILDHOOD ON LIABILITY TO DEPRESSION MODERATED BY 5-HTT GENE(from Caspi et al., 2003)

.70

s/s = short allele homozygous

l/l = long allele homozygous

s/l = heterozygous

s/s

s/l

.60

.50

Probability of major depression episode

.40

l/l

.30

.20

0

slide12

ANTISOCIAL BEHAVIOR AS A FUNCTION OF MAOA ACTIVITY AND A CHILDHOOD HISTORY OF MALTREATMENT(from Caspi et al., 2002)

Composite index of antisocial behavior

(z scores)

Childhood maltreatment

slide13

EFFECTS OF 5-HTT GENOTYPE ON RIGHT AMYGDALA ACTIVATION IN RESPONSE TO FEARFUL STIMULI (from Hariri et al., 2002)

% BOLD fMRI signal change

Long allele group Short allele group

5-HTT genotype

myth v
MYTH-V
  • Effects of variations in normal experiences are similar to the effects of extremely abnormal experiences

Wrong because

    • Whereas abundant evidence of long-term effects of physical & sexual abuse,butlack of evidence of effects of variation in level of corporal punishment
    • Genetic findings highlight the differences between corporal punishment & physical abuse
common factors model of the association between corporal punishment and antisocial behavior
Common factors model of the association between corporal punishment and antisocial behavior

Jaffee et al., 2004

common factors model of the association between corporal punishment and maltreatment
Common factors model of the association between corporal punishment and maltreatment

Jaffee et al. 2004

quantification of marriage effect sampson et al 2006
QUANTIFICATION OF MARRIAGE EFFECT (Sampson et al., 2006)

Reduction in crime rate of age period 17-32 taking into account age variation and persistent heterogeneity

= 36% to 49% (average 43%)

Reduction in crime rate of age period 17-7- taking into account age variation and persistent heterogeneity

= 16% to 64% (average 36%)

myth vi
MYTH-VI
  • Because the effects of ‘ordinary’ adult experiences do not usually change neural structure, they are unlikely to have major psychological effects

Wrong because

Replicated examples of major turning points effects in adult life associated with, for example, marriage

myth vii
MYTH-VII
  • If early experiences are both probabilistic and individually varied in their effects, there is no point in focussing interventions especially on the early years of life

Wrong because

    • Early experiences come first and may, therefore, shape later experiences
    • In some circumstances, extreme early experiences may have marekedly enduring effects

But partially right insofar as

    • Effective early interventions do not obviate the need for attention to later experiences
    • Lasting effects of early experiences do not mean that effects are fixed and cannot be modified
childhood behavior and adult psychosocial stressors adversities data from robins 1966
CHILDHOOD BEHAVIOR AND ADULT PSYCHOSOCIAL STRESSORS/ADVERSITIES (data from Robins, 1966)

%

slide22
SEVERE EVENTS AND DIFFICULTIES IN EARLY ADULT LIFE AND TYPES OF DISTURBANCE AT 10 YEARS IN FEMALES (Champion et al., 1995)

Mean number of events/ difficulties

slide23

AN IMPORTANT ‘NATURAL EXPERIMENT’ FOR TESTING CAUSAL HYPOTHESES ON ENVIRONMENTALLY MEDIATED RISKS

  • Because: Profound deprivation followed by above average rearing environment provides opportunity to study effects of radical environmental change.
  • Children placed in institutions in early infancy
  • (so no selection into institutions on basis of child handicap)
  • Duration of deprivation a function of the child’s age at the time of the fall of the Ceauşescu regime
  • Longitudinal data allows study of within-individual change
  • Change of environment rapid and easily timed
head circumference on uk entry
HEAD CIRCUMFERENCE ON UK ENTRY

Subnutrition No subnutrition

SD

operational criteria for deprivation specificity
OPERATIONAL CRITERIA FOR DEPRIVATION-SPECIFICITY
  • Present before age 6 years
  • Distinctive features that differ from other patterns
  • DSP much more common in children experiencing institutional deprivation at age 6 mo, or later
  • DSP rare in groups not experiencing institutional deprivation
  • Persistence to age 11 years
  • DSP accompanied by substantial functional impairment
  • DSP evident following deprivation not accompanied by subnutrition
criteria for specificity for each dsp
CRITERIA FOR SPECIFICITY FOR EACH DSP
  • Q-A The pattern that is most obviously DSP. No additional criteria needed
  • D-A The next most clear-cut DSP but less obviously requiring deprivation in addition to institutional care. Also measures less satisfactory. Essential to require persistence
  • CI Major overlap with other DSPs but also

I/O found in the absence of institutional

deprivation

association between institutional deprivation and deprivation specific patterns at 15 years
ASSOCIATION BETWEEN INSTITUTIONAL DEPRIVATION AND DEPRIVATION-SPECIFIC PATTERNS AT 15 YEARS
overall conclusions
OVERALL CONCLUSIONS
  • Early years are not determinative
  • Nevertheless, early years are particularly important because
    • They come first, & so many shape later experiences
    • In some circumstances extreme environments may bring about lasting biological effects
  • Early interventions are not likely to be sufficient on their own: later interventions are also crucial
  • Much remains to be learned on the key elements in effective interventions and on the factors that underlie individual differences in response