Module 1: Introduction to Development

Content

  1. Characteristics of lifespan development

  2. Influences of development

  3. Difference in development of monozygotic vs dizygotic twins

  4. Gene-Environment correlations

  5. Two major types of kinship studies

  6. Difference between direct, bidirectional, and indirect influences on development

  7. Major developmental theories conceptualisation

Influences on Development

Cultural, social and historical factors influencing development:

  • Normative age-graded influences: similar biological influences for individuals at the same age - Ex: puberty

  • Normative history-graded influences: why people born at the same time (cohort) tend to be similar - impact of historical circumstance on a generation

  • Non-normative life events: unique occurrences that impact on the individual, independent of historical period

Major Developmental Theories

Psychoanalytic: Freud and Erikson

  • People move through a series of stages where they confront conflicts between biological drives and social expectations

  • Psychosexual stages of development and how three parts of personality (id, ego, and superego) become integrated throughout these stages

  • Freud was the first person to emphasise the importance of the parent-child relationship on development

Erikson saw development as continuing throughout the lifespan, with fundamental psychosocial conflict at every stage, as opposed to Freud

Birth - 1 yr: Basic trust vs mistrust

1 - 3 yrs: Autonomy vs Shame and Doubt

3 - 6 yrs: Initiative vs Guilt

6 - 11 yrs: Industry vs Inferiority

Adolescence: Identity vs Role Confusion

Early adulthood: Intimacy vs Isolation

Middle age: Generativity vs Stagnation

What is Developmental Science?

Developmental science is a field of study devoted to understanding constancy and change throughout the lifespan.

Theory: an orderly integrated set of statements that describe, explain, and predict behaviour

Importance of theories:

  • provide organising frameworks for our observations of people - guide and give meaning to what we see

  • are verified by research provide a sound basis for practical action

Continuous/Discontinuous Development

Continuous development: the idea that development is a smooth process - individuals gradually add more of the same types of skills

Discontinuous development: people change rapidly as they step up to a new level and then change very little for a while

Discontinuous development theory implies that a person goes through stages - qualitative changes in thinking, feeling, and behaving, whereas the continuous development theory argues that its the quantity of skill apprehension that divides development stages.

Development is lifelong, multidimensional and multidirectional, highly plastic, and affected by multiple interacting forces

Lifelong: physical, emotional/social, and cognitive change occurs continuously throughout life

Multidirectional: over time can be progress or regress

Genetic Code

DNA: a long double-stranded molecule that looks like a twisted ladder; each rung of the ladder consists of a specific chemical substances called bases, it is the sequence of base pairs that provides genetic instructions

Gene: a segment of DNA along the length of the chromosome; can be different lengths from a hundred to several thousand rungs long.

21,000 protein-coding genes, and 18,000 regulator genes

Bases: Adenine with Thymine; Cytosine with Guanine

Humans share a lot of their genetic code with other species (95% with chimpanzees), and 99.6% with other humans. It only takes a change in one pair of DNA base to influence human traits, hence the drastic differences between us.

Why are humans so much more complex than other species, despite not having a lot of genes?

  • Simpler species have far fewer proteins

  • In-cell communication between nucleus and cytoplasm far more intricate

  • Environmental factors modify gene expression

Sex cells

Gamete: sperm or ovum cells - have 23 chromosomes each

Meiosis: the process of gamete formation which halves the number of chromosomes normally present in the body and is responsible for creating genetic variability.

  • Genetic variability ensures that at least some members of a species will survive

Zygote: the cell resulting from gametes uniting - 46 chromosomes

About 22 out of 23 chromosome pairs are matching pairs called autosomes (not sex chromosomes), the 23rd pair is sex chromosomes (XX; XY)

Multiple offspring is more common when taking in-vitro fertilisation, fertility drugs, and in case of older maternity age

  • Ethnicity: most common among black africans, then white europeans, than asians and hispanics

  • Family history of twinning

  • Occurs more often among normal weight and overweight women, less often among skinny women

  • More likely with each additional birth