PSYC 1000Lecture 37

Developmental Psychology•Developmental Psychology

–Area of psychology that is concerned with changes in physical and psychological functioning

–Occur from conception across entire life span

Studying Development• How do we study changes over time?

– Normative investigations• Describe characteristics of a specific age or

developmental stage (average level – norms)• Chronological & developmental age

– The same concept as in IQ testing

• Being early or late, with respect to norms is not necessarily catastrophic, however, there are sensitive periods for certain developmental milestones

– E.g. The feral child Victor aka “the wild boy of Averon” discovered by French physician Jean Itard in the 1800s. Victor was not able to learn language.

– Longitudinal design• Repeated observation & testing of the same

people over time– Participants function as their own controls– Helps control for “generational” effects– Not always feasible a particular cohort may be unique

– Cross-sectional design• Groups of participants of different chronological

ages are observed and compared at the same time

• Much more feasible for experimenters• Prone to confounds related to “generational”

differences

Prenatal Development

40 days 45 days 2 months 4 months

Prenatal Development• Zygote

– Fertilized egg: many (50%) never survive– Followed by 3 week period of rapid cell

division– Develops into embryo

• Embryo– Developing organism from 3 to 8 weeks

• Fetus– Developing organism from 3 weeks after

conception to birth

Challenges to Prenatal Development

• Teratogens– Agents that can reach embryo or fetus during

prenatal development and cause harm• e.g., viruses, chemicals, drugs, alcohol

• Fetal Alcohol Spectrum Disorder (FASD)– Caused by pregnant woman’s drinking.

• Debated surrounding what the threshold level is – surgeon general recommends abstaining from alcohol completely during pregnancy

– Physical and Cognitive abnormalities in children– Symptoms include facial misproportions,

behavioral and cognitive difficulties. Now leading cause of mental retardation.

Challenges to Prenatal Development

• Drug Use• Prematurity, birth defects, addiction• Effects vary based on dose and exposure date

– Cocaine and Heroin • Miscarriage or premature birth• Birth defects• Attentional problems

– Smoking

• Prenatal malnutrition– Apathy, irritability, reduced immunity

• Maternal disease– HIV-infection and Aids

• Emotional Stress

Genetics vs. prenatal factors• Many effects that were originally

attributed to genetics or heritability may actually be the result of systemic differences in prenatal environment– E.g. Goddard’s work with the Kallikak family

that was attributed to heredity may have actually resulted from systemic alcoholism leading to fetal alcohol syndrome.

– Similar potential confound when looking across socioeconomic status

Effects of Teratogens at Fetal Ages

Survival Mechanisms

•Babies are prewired for survival …–Preferential responding to stimuli (auditory & visual)

•Human faces, sound of mothers voice–Generalizes to other stimuli (i.e. top heavy visual stimuli)

–Perceptual capabilities associated with movement•The visual cliff (Gibson & Walk, 1960)

Growth & Maturation

•Physical growth is not equal across all physical structures

•Maturation

–Refers to the process of growth typical of all members of a species who are reared in the species’ usual habitat

–Interaction of biological boundaries & environmental inputs

Physical Changes in Youth• Primary physical change associated with the

beginning of adolescence is puberty

– The attainment of sexual maturity

• Males = production of live sperm• Females = menarche (onset of menstruation)

• Also associated with physical growth, development of sexual features, changes in frontal lobes

• Hormones that are secreted from testes and ovaries also interact with other neural systems and have an impact on stress-regulatory systems

Physical Changes in Adults• Many types of physical changes may occur due to misuse more than aging– Physical exercise is important to maintain muscle tone and

good cardiovascular fitness.

– Physical appearance – skin, hair, height• Not a set date, individual variability

– Visual changes – yellowing and loss of flexibility of lens of eye, diminished colour vision

– Hearing changes – problems with high frequency sounds, greater in men

• Pronounced in later adulthood but changes are detectable even in early adulthood.

– Sexual functioning – menopause in women & reduction in quantity of sperm

• As in puberty, there are associated changes in mood etc. as well as the more obvious physical changes