Developmental Psychology Flashcards
Genotype
Total complement of genes inherited by the organism
Gene
Molecules on the chromosomes that transmit the hereditary blueprint
Chromosomes
Threadlike structure made up of genetic material - in humans, there are 46 chromosomes in every cell (except sperm and ova)
Sex cells (gametes):
Sperm and ova (these cells have 23 chromosomes)
Twin studies
Carried out to determine whether character is due to genetics or environment; found that similarities in character became clearer over time (as people get older, they can choose their own environment)
Cooper & Zubek 1958
Found that Maze Bright rats (genetic) had fewer errors in standard environment, but similar number of errors to Maze Dull rats in enriched and impoverished environments
Genes and environment (intelligence)
Genes determine range of possible IQs, while environment determines where the individual ends up on that range
Genes and environment (schizophrenia)
Influenced by both genes and environment (higher risk of developing schizophrenia for both close genetic family and adopted)
Teratogen definition
Agent that causes some sort of deviation during development (pregnancy)
Teratogen: Thalidomide (late 1950s and early 1960s)
Prescribed during the first trimester of pregnancy for nauseau; affects limb development by preventing new blood vessel growth
Critical period
Time in development when specific biological or environmental events have dramatic and irreversible effects on development (humans: 18 to 60 days from conception)
Teratogen (alcohol)
Reduces oxygen supply to foetal brain and interferes with hormone metabolism –> foetal alcohol syndrome (FAS) - caused by carrier ingesting high amount of alcohol during foetal period (week 10 to birth)
Konrad Lorenz (imprinting)
Found that grey geese have a critical imprinting period of 13 to 16 hours after hatching
Social development in non-human primates (consequences of isolation): Henry Harlow (experimented from 1957-1963)
Found that:
1. Social isolation increases self-directed and stereotypic behaviour (rocking, biting, etc.)
2. Causes deficits in social behaviour directed at others
Social development in non-human primates (rehabilitation): Henry Harlow (experimented from 1957-1963)
Found that pairing isolates and normal, younger monkeys allowed isolates to experience physical affection without negative consequences, and allowed the isolate to recover socially; evidence against a critical period for social behaviour (or critical period may be longer than 12 months)
Complete social isolation of a human child: Oxana Malaya
Born in 1983, discovered at age eight after having spent six years of her life living with dogs (growled, barked, etc.), has been somewhat rehabilitated but is still not fully ‘normal’; argues for a window of opportunity where the brain has the capacity to form connections
Bowlby 1948
Found that children in foster homes displayed increased attention-seeking behaviour, apathy and withdrawal from social situations, as well as cognitive and language impairments (little opportunity for brain to develop in those areas due to lack of exposure to human language)
Harold Skeels (1930s)
Found that children who were adopted out of a foster home were more likely to be ‘successful’ and have normal family lives and IQs, while those who stayed had lower IQs and were more likely to remain in an institution; compared IQs before being taken out of foster care and after
Dennis 1973
Found that the earlier that children were taken out of social isolation (adopted), the better their IQ outcome
Critical period
- Period during development when the organism is particularly susceptible to the effects of a particular experience
- Effects are dramatic and irreversible
- Sharp onset and offset points
Sensitive period
- Period during development when the organism is particularly susceptible to the effects of a particular experience
- Harmful effects can be altered by later events; effects are less dramatic
- Begins and ends gradually
Perry 2002
Found that the earlier children were removed from situations of neglect and placed in foster care, the greater their brain volume (frontal-occipital circumference/ FOC)
Substance abuse and child abuse
Children of substance abusers are more likely to be abused and neglected
Cycle of abuse
People abused as children are more likely to abuse their own children
Age of abuse
As children get older, the rate of abuse goes down
Age of fatalities
Highest for children of less than one year; younger children are overrepresented in abuse fatalities
Poverty and child abuse
Financial pressure creates stress → more prone to becoming frustrated with child
Silverman, Reinherz, & Giaconia 1996
People who have suffered abuse are more likely to experience mental health issues/ disorders
Child abuse and health
People who have suffered abuse are more likely to experience health problems in middle-age
Shaken baby syndrome
Brain injury when baby is violently shaken (usually younger than two, but can be up to five years); occurs due to weak neck muscles and large, heavy head (brain bounces back and forth inside skull causing bruising, swelling, tissue damage, etc.)
Keran Henderson 2005
Convicted of violently shaking 11-month toddler to death
Prognosis of shaken baby syndrome:
Retinal damage –> blindness; majority of infants have a mental disability, possibly not evident before six years of age
Chen et al. 2002
If they’ve ever smoked cigarettes, what are the odds that they drank alcohol in the last 30 days → found that people who have smoked before are more likely to have drank in the past 30 days
Torabi et al. 1993
Teens who smoke a pack or more of cigarrettes a day are at increased risk of using illegal drugs
Gateway drug hypothesis
- Sequencing: One substance is regularly initiated before another
- Association: One substance increases likelihood of second substance
- Causation: Use of first substance actually causes use of second substance
Gateway drug hypothesis: Perceptions of risk
Initial decision to accept risk of tobacco makes risk with other drugs seem less severe
Portugal and cannabis
Decriminalisation of drugs resulted in the same cannabis use as before, and lower use of other previously illegal drugs; drug-induced deaths decrease (evidence against gateway drug hypothesis)
Vaginal delivery
During vaginal birth, the birth-giver releases the hormone oxytocin, which stimulates maternal behaviour
Swain et al. 2008
Found greater responsiveness in the brain to sound of own baby crying for people who gave birth vaginally as compared to people who had a C-section, but greater responsiveness was also linked to higher rates of depression in birth-givers
Wittfoth-Schardt 2012
Found that oxytocin given to fathers increased contact with children and led to more affectionate parenting
Language (learned in part in the womb): At birth, what can infants do?
- Prefer forward-going speech to backward-going speech
- Prefer their own language
- Can discriminate function words from content words on the basis of different acoustic properties
- Prefer birth-giver’s voice to others’ voices
- Discriminate most sound contrasts used in today’s languages
Language: By one year of age, what can infants do?
Can only make contrasts present in their own language
Noam Chomsky
‘Nativist’, argued that certain aspects of language are innate due to poverty of the stimulus (language input to child typically insufficient to be learnable); believed in a universal grammar all languages share
Behaviourist theory: Language
Argued that parents reward children for grammatical utterances and punish them for incorrect grammatical utterances, but this does not occur
Learning theory: Language
Language isn’t learned through reward (approval) and punishment (disapproval) –> must be innate
What do learning theorists believe today?
Language can be learned using general learning mechanisms such as statistical learning, which allows for the learning of patterns
Statistical learning: Language
- Grammatical categories occur in predictable positions in sentences; infant quickly identifies a pattern
- Brain is specialised for statistical learning, which assists in language learning - statistical learning allows for the identification of a ‘word’
- Babies use transitional probabilities (how likely a syllable/ syllables are to be followed by another certain syllable/ syllables; example: ‘mum’ is consistently followed by ‘my’) to figure out what a word is
Teinonen et al. 2009
Found that newborn infants’ brains respond differently to new and old words even when asleep; familiarity is used to group together sounds into words. This was seen through measured brain activity.
Baldwin et al. 2001
Found that infants paid greater attention to predictable actions stopped halfway through than completed predictable actions; indicates that infants learn to predict patterns in behaviour and therefore find it unusual when the behaviour is not completed (they work out the mental states behind the behaviour later)
Effects of impaired statistical learning:
Specific language impairment (SLI): Affected individuals use short sentences, have small vocabularies, word-finding problems, and difficulty learning new words; high proportion go on to experience reading difficulties, develop dyslexia
Evans et al. 2009
Found that typically-developed children had better-than-chance statistical learning, while children with SLI were not generally above-chance for statistical learning; within each group, those who were better on statistical learning task with words were better on a measure of language ability
Autism definition
Neural disorder characterised by qualitative deficits in social interaction, communication, and imaginative ability; can be inherited
Autism and statistical learning
Typically-developing kids can distinguish between pattern syllables and non-pattern syllables, unlike autistic kids, who do not learn about the pattern
Michael & Zucker 1995
Found that lesbians reported a higher rate of cross-sex typed behaviour in childhood than straight women, and the same was true for gay men
Green 1987
Found that boys identified as ‘feminine’ were more likely to be gay later in life
Kinsey rating scale
Measured sexuality with only two options: straight or lesbian
Diethylstilbestrol (DES) and sexuality
Synthetic oestrogen; exposure to it in foetal development impacted on sexual orientation
Ward 1972
Found that stress during pregnancy impacted testosterone present in the developing brain of foetus (hormone caused by stress blocks it)
Dorner et al. 1983
Interviewed people regarding stress levels during pregnancy → found that severe stress of the birth-giver was associated with greater rates of offspring being homosexual or bisexual
Ellis et al. 2001
Found that greater psychological stress of the pregnant person was associated with a higher possibility of offspring being gay (in male people) or bisexual (female)
Maternal smoking and sexuality
Maternal smoking → male bisexuality and female homosexuality
Manning 2001
Claimed one in seven gay men owe sexual orientation to their birth order
Blanchard et al. 1995
Found that gay men are often born later and have older brothers; this is because antibodies are developed by the birth-giver to respond to being pregnant with a male foetus (antibodies attack protein only made in males) –> antibodies build up in the birth-giver’s blood with each male foetus they carry, resulting in a decrease in protein only produced in males (acts as ‘switch’ for so-called gay gene)
Savic & Lindström 2008
Found that for gay men and straight women there was not difference in brain volume between left/ right halves of the brain, while for lesbians and straight men the right side was bigger; differences in brain lateralisation likely to do with environment of the womb during foetal development
Geschwind & Galaburda 1985
Found that foetal testosterone compromises development of left hemisphere and facilitates right hemisphere functioning
Fruit flies and sexuality
Stronger synapses in fruit flies associated with increased homosexual activity
Roselli & Stormshak 2009: Gay sheep
Found that volume of the area of the hypothalamus associated with sexuality is determined by exposure to testosterone and estradiol around the time of birth (the perinatal period); larger volume of the area for straight rams
What controls sexuality in rams and humans?
Hypothalamus
Zietsch et al. 2008: Explanation for why queer genes stay in the gene pool
Argued that the same genes that produce same-sex behaviour also produce some degree of non-stereotypical personality –> when such an individual is heterosexual, they have more sexual partners (‘gay’ gene gives a mating advantage)
Other explanation for why queer genes stay in the gene pool:
Female relatives of gay men have more children
Shaken baby syndrome (what proportion of child abuse deaths does it account for)
Accounts for up to half of child abuse deaths in the U.S.
