Developmental Psychology
Lecture 1
Goal 1: What is developmental psychology?
Narrow conception of development (how the definition developed)
- Sequential - based on several stages/ levels/ phases, after you master one phase you can move on to the next one
- Unidirectional - earlier changes are prerequisite for later ones, once you master something you keep it, no way back
- End state - higher value than the original state
- Irreversible - in progression - Qualitative - structural transformations
- Biological growth - independent of culture, biological changes - Universal - the same for all humans
Developmental Psychology across the lifespan
Time from conception until adulthood→after you 20 you fully developed=not the case, development continues→extended
Extended conception of development
- not necessarily based on stages, which build up on each other
- not always end states, which are of higher value (e.g., personality)
- qualitative as well as quantitative (e.g., language development, learn grammar rules, vocabulary expands)
- can be universal but also interindividually different (one child can start walking with 10 month another with 14)
- affected by culture and biology
- can be intraindividually modifiable (plastic) and constrained (not everyone reaches the potential end stage)
→Individuals develop over time + Development takes place across the entire lifespan
Developmental psychology: Definition
▪ Developmental Psychology deals with behavioral changes within persons across the lifespan, and with differences
between and similarities among persons in the nature of these changes.
▪ Its aim is not only to describe these intraindividual changes and interindividual differences but also to explain how they
come about and to find ways to modify them in an optimum way.
Goal 2: What develops when, how, and why?
The “What” in developmental psychology →Social changes, Cognitive changes, Biological changes, Emotional changes
Development in different fields of psychology
▪ You can learn a new language anytime in your life, but can you reach the same level in the same amount of time?
▪ Individuals differ in personal characteristics – however, how stable are they across the lifespan or do they change?
▪ Which skills are needed for which work context, and what if these skills change across the lifespan?
▪ Individuals gain from cognitive training, who gains most and why? Which training is effective for whom at which point?
Typical question for lifespan developmental psychologists
▪ Which competences, attitudes and interests can be expected from an infant, a primary school child, a teenager, an adult
and an older adult?
▪ What is the minimum age at which legal capacity, the right to vote, age of criminal responsibility, marriageability and
retirement age should be set?
▪ Are there inter-individual differences in developmental changes across functions?
▪ In which periods of development do we have to expect which typical risks, crises or problems?
▪ Is it possible to influence developmental changes?
▪ What must be mediated or avoided in which age periods so that no lasting damage occurs?
Developmental psychology focuses on...
Normative (=typical) development, but also individual differences:
▪ Which deviations from the norm are likely? ▪ How can they be explained? ▪ What do they mean for future life? Are they
stable, are they changeable? ▪ How can future developments be influenced in a favorable way? ▪ How can people be
immunized against harmful influences? ▪ How can we increase the probability of coping with adverse events?
The “When“ in lifespan developmental psychology
What develops when? ▪ When studying normative development, we link important developmental changes to a certain age
(just a number to classify people, not very informative) ▪ How can we classify these age periods?
Two phases of old age (subcategories)
Young-old: ~60/65-80 years → ▪ Still relatively healthy ▪ Active
Old-old: from ~80 years on → ▪ Increased risk for physical and cognitive problems
But huge differences between individuals (age not very informative)
1
,What develops when? - IMPORTANT: Biological age is never responsible for and thus does not explain changes.
▪ Changes can only be correlated with age – “vehicle” of change
▪ Goal = link changes to „why“: which mechanisms drive development? what is happening at a certain age that explains
why we observe something→see changes at 34=brain is still developing→focus on mechanisms
Time scale of development:
▪ Variability (= short-term changes that are more or less reversible) vs. change (= more or less enduring)
▪ Variability can predict change→a lot of variability before there is cognitive decline→the more variability we see, the most
likely are changes→eg. fatigue, bad sleep leading to long lasting changes
We can treat age…
...in a continuous way →age x ability correlation (scatterplot)
...compare specific age groups→mean age difference in ability X (select age groups, average across them and compare)
We can investigate ...
...individuals of different ages at one point in time→Cross-sectional designs →here we measure differences, not change bc
we don’t know what these people went through in life, cannot compare their change but their differences
... the same individuals across different points in time→Longitudinal designs→here we measure change
→we know exactly what that person was doing 2 years before so we can measure change
If I measure your knowledge of developmental psychology now and at the end of the course, what research design would
we apply? A longitudinal design→same group measured across time
Research designs
Cross-sectional designs → Studying groups of individuals of different ages at one point in time
→ Measure interindividual differences
Longitudinal designs → Studying one group of individuals over a longer time period → Measure intraindividual change
Cohort effects
Cohort = any group that shares having experienced the same cultural environment and historical events (e.g., same year of
birth) eg. higher loneliness during covid than now comparing people that are the same age
▪ Cohort effect = Differences in developmentally relevant variables that arise from (non-age-related) factors to which each
birth cohort is exposed→differences from being exposed to different environments
→ observed results caused by cohort characteristics, but not development
Can cohort effects be a problem for cross-sectional and longitudinal designs?
1. Is cheaper →cross sectional
2. Can be affected by test-retest effects→ longitudinal (test people more than once)
3. Provides information about individual paths→ longitudinal
Cross-sectional designs
Advantages→▪ Economic in time (short duration between assessment and results) ▪ Rather cheap
▪ Shows similarities and differences between age groups
Disadvantages→ ▪ No information on individual trajectories (interindividual differences instead of intraindividual change)
▪ Age effects confounded with cohort effects ▪ Limited generalizability to other times of measurement
Longitudinal designs
Advantages→ ▪ True assessment of intraindividual change
▪ Assessment of stability and change of developmental characteristics
Disadvantages→ ▪ Age effects confounded with time-of-measurement effects / retest effects / attrition effects
▪ Limited generalizability to other cohorts ▪ Long duration (people might drop out) ▪ High costs
Sequence models
2
,Assessment methods
▪ Self-report vs. report by proxy (e.g., parent, spouse, caregiver) ▪ Interview ▪ Questionnaires ▪ Diaries
▪ Behavioral observation [naturalistic versus structured=invite them to the lab with a structured scene, eg parent leaving the
child, then comes back→create situations] especially with children
▪ Standardized Tests/Test batteries [comparison to norms/typical behavior]
▪ Experiments [Comparison of age groups or experimental conditions with behavioral or neuro-biological data as outcome]
You watch and write down children's problem behavior on the schoolyard→Behavioral observation
Research challenges
In developmental research, we focus on age groups (infants, children, older adults) that may differ from younger adults in:
▪ Speech reception and production ▪ Sensomotoric abilities ▪ Suggestibility ▪ Attention span/Fatigue ▪ Subjective meaning of
concepts ▪ Proportion of undiagnosed clinical impairment
Adjust methods to abilities of individual!
▪ Age-adjusted task material ▪ Oral responses instead of written ▪ Non-verbal task material
▪ Use of structured observation, physiological methods or report by proxies as alternatives to verbal self-report
▪ Consider selectivity of sample → representative? (e.g., mobile older adults with high cognitive functioning, people with
motion problems don’t come to the lab, so they are excluded from the sample)
▪ Response bias: social desirability, accuracy-speed trade-off (sacrifice the speed for accuracy, take longer to give the
perfect answer), stereotypes (can influence the responses)
Research challenges: Infant research
Example: Baby‘s can’t speak...How do you meet the response of a baby? How do you what a baby likes or finds interesting?
Habituation / Dishabituation
1. Orienting response→ look where they are interested
2. Habituation: slow, changed, or stopped response to repeated presentation of the same stimulus
3. Dishabituation: increase in responding to a new stimulus or habituated stimulus after introducing a deviant→response
goes up again, but maybe not as strong as the first time bc it’s a similar stimulus→in this way i can see if they recognize eg
2 cars of different colors as the same object
Research challenges: Experimental infant research
How to measure a response by an infant? Sucking preference→indicator of response
Head turn preference →check their preference Paired visual preference→eye tracking
Assumption: Looking, sucking, turning head: interested, surprising outcome, noticed a difference
NOT looking, sucking, turning head: loss of interest, recognized as old, did not notice a difference
Research challenges: Experimental aging research
One example: Age Stereotype Threat
• Same study material but different instructions: “The goal of the study is to assess your...” asked to highlight certain things
1. Memory abilities: „...will allow to diagnose whether memory is normal”
2. Reading ability “...will allow to assess if reading ability is normal”
there are many stereotypes in memory problems than in reading problems in older adults→memory performance very low
bc of the stereotype of bad memory in older age
The “How“ in lifespan developmental psychology
Principles of lifespan psychology Development is...
1. Lifelong 2. Multidimensional and multidisciplinary 3. Multidirectional 4. Gains and losses 5. Plastic 6. Embedded in
history 7. Contextualized
2. Multidisciplinarity
Human development has to be seen in a multidisciplinary way: need to take them all into account
• Biologists • Neuroscientists • Historians • Economists→economic conditions • Sociologists • Anthropologists • ...
3. Multidirectionality
Contrary to earlier assumptions, development is not a universal process leading in one direction (→ more “mature”
functioning) →Different capacities show different patterns of change over time
Differences between individuals in:
• Different features begin to appear at different times
• Mature at different rates • Decline at different rates
• Begin to decline, if decline they do, at different times and different brakes
3
, There are large inter-individual differences in development
No individual is the average! No one single person will follow that exactly
4. Gain-loss dynamic across the lifespan
Development always consists of the joint occurrence of gain (growth) and loss (decline)
▪ Example: Language recognition and language acquisition in childhood – loss in the context of specialization
the higher we get, the more the losses are compared to the gains→even at the very beginning of life there are some losses
4. Shifting balance between gains and losses
because more losses appear with time, more activities/things need to be done to balance them
5. Plasticity and constraints
• Vulnerable individuals are most vulnerable in aversive environments, but may also benefit most in positive environments
6. Historical embeddedness
• Course of age-related development strongly shaped by the prevailing socio-cultural conditions of a historical period →
cohort effects. Examples:
• Health care system • Social support systems (e.g., unemployment benefits) • Pension system
• Generation effects like having experienced war, growing up with technology, …
• Prevailing societal conventions like acceptance of spanking in child rearing
7. Contextual developmental influences
What influence is the Covid-19 pandemic? Normative history-graded / Non-normative
Interaction of Biological and “Cultural” Factors in lifespan development: Three assumptions
→ Development takes place within supporting and limiting influences
→ More biologically-based performance and functions change differently across the lifespan than more culturally-based
performance or functions.
* Culture = entirety of psychological, social, material, and knowledge-based resources, such as cognitive
skills, motivational dispositions, socialization strategies, physical structures, the world of economics as well that of
medical and physical technology.
Lecture 2 Why do we develop
Goal 1: What are important debates in developmental psychology? Discussions in developmental psychology
1. Nature vs. Nurture
Is development primarily the product of genes, biology, and maturation - or experience, learning, and social influences?
Nature: The way you were born e.g., genes and hereditary factors
Nurture: The way you were raised e.g., childhood experiences, surrounding culture
The truth lies in between… Nature-nurture interactions
Nature-nurture interactions: Critical/sensitive period
Critical period→is a maturational period in which the nervous system is especially sensitive to certain environmental stimuli.
If the organism does not receive the appropriate stimulus at the right time, it is impossible to catch up, to develop certain
associated functions later in life. If deprived of stimuli in this period→they never caught up
Example→binocular vision Are there critical periods to develop a skill?
Lorenz and his ‘children’: Imprinting
incubator-hatched geese imprint on the first suitable moving stimulus they saw within "critical period"
between 13–16 hours after hatching →they followed him and not the mother because he was the first thing they saw
In psychology we have more the idea of:
Sensitive period→is a maturational period in which specific experiences have maximal positive or negative effects: Periods
of increased plasticity under the influence of specific condition factors.
Examples: language development→if infant not exposed to any language it is possible to catch up but much slower and do
not reach the same level of people that learned on time
Nature-nurture interactions
1. Gene-environment interactions nature × nurture
2. Gene-environment correlations nature➔nurture
3. Epigenetics nature←nurture (nature influenced by the environment)
1) Gene–environment interaction ×
4
Lecture 1
Goal 1: What is developmental psychology?
Narrow conception of development (how the definition developed)
- Sequential - based on several stages/ levels/ phases, after you master one phase you can move on to the next one
- Unidirectional - earlier changes are prerequisite for later ones, once you master something you keep it, no way back
- End state - higher value than the original state
- Irreversible - in progression - Qualitative - structural transformations
- Biological growth - independent of culture, biological changes - Universal - the same for all humans
Developmental Psychology across the lifespan
Time from conception until adulthood→after you 20 you fully developed=not the case, development continues→extended
Extended conception of development
- not necessarily based on stages, which build up on each other
- not always end states, which are of higher value (e.g., personality)
- qualitative as well as quantitative (e.g., language development, learn grammar rules, vocabulary expands)
- can be universal but also interindividually different (one child can start walking with 10 month another with 14)
- affected by culture and biology
- can be intraindividually modifiable (plastic) and constrained (not everyone reaches the potential end stage)
→Individuals develop over time + Development takes place across the entire lifespan
Developmental psychology: Definition
▪ Developmental Psychology deals with behavioral changes within persons across the lifespan, and with differences
between and similarities among persons in the nature of these changes.
▪ Its aim is not only to describe these intraindividual changes and interindividual differences but also to explain how they
come about and to find ways to modify them in an optimum way.
Goal 2: What develops when, how, and why?
The “What” in developmental psychology →Social changes, Cognitive changes, Biological changes, Emotional changes
Development in different fields of psychology
▪ You can learn a new language anytime in your life, but can you reach the same level in the same amount of time?
▪ Individuals differ in personal characteristics – however, how stable are they across the lifespan or do they change?
▪ Which skills are needed for which work context, and what if these skills change across the lifespan?
▪ Individuals gain from cognitive training, who gains most and why? Which training is effective for whom at which point?
Typical question for lifespan developmental psychologists
▪ Which competences, attitudes and interests can be expected from an infant, a primary school child, a teenager, an adult
and an older adult?
▪ What is the minimum age at which legal capacity, the right to vote, age of criminal responsibility, marriageability and
retirement age should be set?
▪ Are there inter-individual differences in developmental changes across functions?
▪ In which periods of development do we have to expect which typical risks, crises or problems?
▪ Is it possible to influence developmental changes?
▪ What must be mediated or avoided in which age periods so that no lasting damage occurs?
Developmental psychology focuses on...
Normative (=typical) development, but also individual differences:
▪ Which deviations from the norm are likely? ▪ How can they be explained? ▪ What do they mean for future life? Are they
stable, are they changeable? ▪ How can future developments be influenced in a favorable way? ▪ How can people be
immunized against harmful influences? ▪ How can we increase the probability of coping with adverse events?
The “When“ in lifespan developmental psychology
What develops when? ▪ When studying normative development, we link important developmental changes to a certain age
(just a number to classify people, not very informative) ▪ How can we classify these age periods?
Two phases of old age (subcategories)
Young-old: ~60/65-80 years → ▪ Still relatively healthy ▪ Active
Old-old: from ~80 years on → ▪ Increased risk for physical and cognitive problems
But huge differences between individuals (age not very informative)
1
,What develops when? - IMPORTANT: Biological age is never responsible for and thus does not explain changes.
▪ Changes can only be correlated with age – “vehicle” of change
▪ Goal = link changes to „why“: which mechanisms drive development? what is happening at a certain age that explains
why we observe something→see changes at 34=brain is still developing→focus on mechanisms
Time scale of development:
▪ Variability (= short-term changes that are more or less reversible) vs. change (= more or less enduring)
▪ Variability can predict change→a lot of variability before there is cognitive decline→the more variability we see, the most
likely are changes→eg. fatigue, bad sleep leading to long lasting changes
We can treat age…
...in a continuous way →age x ability correlation (scatterplot)
...compare specific age groups→mean age difference in ability X (select age groups, average across them and compare)
We can investigate ...
...individuals of different ages at one point in time→Cross-sectional designs →here we measure differences, not change bc
we don’t know what these people went through in life, cannot compare their change but their differences
... the same individuals across different points in time→Longitudinal designs→here we measure change
→we know exactly what that person was doing 2 years before so we can measure change
If I measure your knowledge of developmental psychology now and at the end of the course, what research design would
we apply? A longitudinal design→same group measured across time
Research designs
Cross-sectional designs → Studying groups of individuals of different ages at one point in time
→ Measure interindividual differences
Longitudinal designs → Studying one group of individuals over a longer time period → Measure intraindividual change
Cohort effects
Cohort = any group that shares having experienced the same cultural environment and historical events (e.g., same year of
birth) eg. higher loneliness during covid than now comparing people that are the same age
▪ Cohort effect = Differences in developmentally relevant variables that arise from (non-age-related) factors to which each
birth cohort is exposed→differences from being exposed to different environments
→ observed results caused by cohort characteristics, but not development
Can cohort effects be a problem for cross-sectional and longitudinal designs?
1. Is cheaper →cross sectional
2. Can be affected by test-retest effects→ longitudinal (test people more than once)
3. Provides information about individual paths→ longitudinal
Cross-sectional designs
Advantages→▪ Economic in time (short duration between assessment and results) ▪ Rather cheap
▪ Shows similarities and differences between age groups
Disadvantages→ ▪ No information on individual trajectories (interindividual differences instead of intraindividual change)
▪ Age effects confounded with cohort effects ▪ Limited generalizability to other times of measurement
Longitudinal designs
Advantages→ ▪ True assessment of intraindividual change
▪ Assessment of stability and change of developmental characteristics
Disadvantages→ ▪ Age effects confounded with time-of-measurement effects / retest effects / attrition effects
▪ Limited generalizability to other cohorts ▪ Long duration (people might drop out) ▪ High costs
Sequence models
2
,Assessment methods
▪ Self-report vs. report by proxy (e.g., parent, spouse, caregiver) ▪ Interview ▪ Questionnaires ▪ Diaries
▪ Behavioral observation [naturalistic versus structured=invite them to the lab with a structured scene, eg parent leaving the
child, then comes back→create situations] especially with children
▪ Standardized Tests/Test batteries [comparison to norms/typical behavior]
▪ Experiments [Comparison of age groups or experimental conditions with behavioral or neuro-biological data as outcome]
You watch and write down children's problem behavior on the schoolyard→Behavioral observation
Research challenges
In developmental research, we focus on age groups (infants, children, older adults) that may differ from younger adults in:
▪ Speech reception and production ▪ Sensomotoric abilities ▪ Suggestibility ▪ Attention span/Fatigue ▪ Subjective meaning of
concepts ▪ Proportion of undiagnosed clinical impairment
Adjust methods to abilities of individual!
▪ Age-adjusted task material ▪ Oral responses instead of written ▪ Non-verbal task material
▪ Use of structured observation, physiological methods or report by proxies as alternatives to verbal self-report
▪ Consider selectivity of sample → representative? (e.g., mobile older adults with high cognitive functioning, people with
motion problems don’t come to the lab, so they are excluded from the sample)
▪ Response bias: social desirability, accuracy-speed trade-off (sacrifice the speed for accuracy, take longer to give the
perfect answer), stereotypes (can influence the responses)
Research challenges: Infant research
Example: Baby‘s can’t speak...How do you meet the response of a baby? How do you what a baby likes or finds interesting?
Habituation / Dishabituation
1. Orienting response→ look where they are interested
2. Habituation: slow, changed, or stopped response to repeated presentation of the same stimulus
3. Dishabituation: increase in responding to a new stimulus or habituated stimulus after introducing a deviant→response
goes up again, but maybe not as strong as the first time bc it’s a similar stimulus→in this way i can see if they recognize eg
2 cars of different colors as the same object
Research challenges: Experimental infant research
How to measure a response by an infant? Sucking preference→indicator of response
Head turn preference →check their preference Paired visual preference→eye tracking
Assumption: Looking, sucking, turning head: interested, surprising outcome, noticed a difference
NOT looking, sucking, turning head: loss of interest, recognized as old, did not notice a difference
Research challenges: Experimental aging research
One example: Age Stereotype Threat
• Same study material but different instructions: “The goal of the study is to assess your...” asked to highlight certain things
1. Memory abilities: „...will allow to diagnose whether memory is normal”
2. Reading ability “...will allow to assess if reading ability is normal”
there are many stereotypes in memory problems than in reading problems in older adults→memory performance very low
bc of the stereotype of bad memory in older age
The “How“ in lifespan developmental psychology
Principles of lifespan psychology Development is...
1. Lifelong 2. Multidimensional and multidisciplinary 3. Multidirectional 4. Gains and losses 5. Plastic 6. Embedded in
history 7. Contextualized
2. Multidisciplinarity
Human development has to be seen in a multidisciplinary way: need to take them all into account
• Biologists • Neuroscientists • Historians • Economists→economic conditions • Sociologists • Anthropologists • ...
3. Multidirectionality
Contrary to earlier assumptions, development is not a universal process leading in one direction (→ more “mature”
functioning) →Different capacities show different patterns of change over time
Differences between individuals in:
• Different features begin to appear at different times
• Mature at different rates • Decline at different rates
• Begin to decline, if decline they do, at different times and different brakes
3
, There are large inter-individual differences in development
No individual is the average! No one single person will follow that exactly
4. Gain-loss dynamic across the lifespan
Development always consists of the joint occurrence of gain (growth) and loss (decline)
▪ Example: Language recognition and language acquisition in childhood – loss in the context of specialization
the higher we get, the more the losses are compared to the gains→even at the very beginning of life there are some losses
4. Shifting balance between gains and losses
because more losses appear with time, more activities/things need to be done to balance them
5. Plasticity and constraints
• Vulnerable individuals are most vulnerable in aversive environments, but may also benefit most in positive environments
6. Historical embeddedness
• Course of age-related development strongly shaped by the prevailing socio-cultural conditions of a historical period →
cohort effects. Examples:
• Health care system • Social support systems (e.g., unemployment benefits) • Pension system
• Generation effects like having experienced war, growing up with technology, …
• Prevailing societal conventions like acceptance of spanking in child rearing
7. Contextual developmental influences
What influence is the Covid-19 pandemic? Normative history-graded / Non-normative
Interaction of Biological and “Cultural” Factors in lifespan development: Three assumptions
→ Development takes place within supporting and limiting influences
→ More biologically-based performance and functions change differently across the lifespan than more culturally-based
performance or functions.
* Culture = entirety of psychological, social, material, and knowledge-based resources, such as cognitive
skills, motivational dispositions, socialization strategies, physical structures, the world of economics as well that of
medical and physical technology.
Lecture 2 Why do we develop
Goal 1: What are important debates in developmental psychology? Discussions in developmental psychology
1. Nature vs. Nurture
Is development primarily the product of genes, biology, and maturation - or experience, learning, and social influences?
Nature: The way you were born e.g., genes and hereditary factors
Nurture: The way you were raised e.g., childhood experiences, surrounding culture
The truth lies in between… Nature-nurture interactions
Nature-nurture interactions: Critical/sensitive period
Critical period→is a maturational period in which the nervous system is especially sensitive to certain environmental stimuli.
If the organism does not receive the appropriate stimulus at the right time, it is impossible to catch up, to develop certain
associated functions later in life. If deprived of stimuli in this period→they never caught up
Example→binocular vision Are there critical periods to develop a skill?
Lorenz and his ‘children’: Imprinting
incubator-hatched geese imprint on the first suitable moving stimulus they saw within "critical period"
between 13–16 hours after hatching →they followed him and not the mother because he was the first thing they saw
In psychology we have more the idea of:
Sensitive period→is a maturational period in which specific experiences have maximal positive or negative effects: Periods
of increased plasticity under the influence of specific condition factors.
Examples: language development→if infant not exposed to any language it is possible to catch up but much slower and do
not reach the same level of people that learned on time
Nature-nurture interactions
1. Gene-environment interactions nature × nurture
2. Gene-environment correlations nature➔nurture
3. Epigenetics nature←nurture (nature influenced by the environment)
1) Gene–environment interaction ×
4
