Developmental Psychology

Research MethodsLab 1

Research Strategy

Select research method (test, questionnaire, interview, observation)

Decide on research design (overall plan that permits the best test of research idea)

Evaluate procedure for any possible harm to participants

Different Aims; Different Methods

Basic Research e.g., How do infants acquire language?

Applied Research e.g., Do bilingual environments affect language

development? Action Research

e.g., Are outcomes from bilingual schooling positive enough to continue funding?

Hypothesis

Research can: Test a prediction of one

theory against that of another

Test a prediction of one theory

Start with a research question, if there is no theory

A prediction often drawn from a theory.A prediction often drawn from a theory.

Systematic ObservationNaturalistic Observation

In the “field,” or natural environment, where behavior happens

Observation in a day-care about children’s responses to peers’ distress

+ direct observation of everyday behaviour

- not all children have the same opportunity to display a particular behaviour in everyday life

Structured Observations

Laboratory situation set up to evoke behaviour of interest

All participants have equal chance to display behaviour

+ permit greater control over the research situation

+ method is especially useful for studying behaviour that investigators rarely have an opportunity to see in everyday life (e.g. relationships)

- Participants may behave in the laboratory differently as they do in their natural environment

Collecting Systematic Observations

Event Sampling Observer records

all instances of a particular behaviour during a specific time period.

Time Sampling Observer records

whether certain behaviours occur during a sample of short time intervals.

Limitations of Systematic Observation

Observer Influence Participants may react in unnatural ways Can be minimized

Observer Bias Observers record what they expect,

rather than what really happens.

Observed Behaviour Conveys little about the reasoning

that underlies the observed behaviour

Interviews

Clinical Interview

Flexible, conversational style

Probes for participant’s point of view

Structured Interview

Each participant is asked same questions in same way

May use questionnaires, get answers from groups

Self-reports ask research participants to provide Self-reports ask research participants to provide information on their perceptions, thoughts, abilities, information on their perceptions, thoughts, abilities, feelings, attitudes, beliefs, and past experiencesfeelings, attitudes, beliefs, and past experiences

Limitations ofClinical Interviews

Accuracy of participants’ expressions Wish to please the interviewer Trouble recalling exactly Difficulty articulating answers

Distortions in participants’ Recall Judgments

Flexibility may make responses too varied

Psychophysiological Methods

Methods to uncover the biological bases of perceptual, cognitive, and emotional responses

Measure the relationship between physiological processes and behaviour

Help to infer perceptions, thoughts, and emotions of infants and young children

Measures of autonomic nervous system activity

Heart rate (infant staring at a stimulus – heart rate is stable; processing the stimulus – heart rate slows; experiencing distress – heart rate rises)

blood pressure Respiration Pupils stress hormones

Methods of Measuring Brain Functioning

Electroencephalogram (EEG) Detect changes in electrical activity in the cerebral

cortex, which plays a central role in complex mental functions, including attention, perception, memory, language, planning, and problem solving

Brain-wave patterns are examined for stability and organization

Event-related potentials (ERPs) Detect the general location of cortical activity as a

child processes a particular stimulus Often used to study preverbal infants, impact of

experience on development of brain regions, and atypical brain functioning in children at risk for learning or emotional problems

Methods of Measuring Brain Functioning (Neuroimaging techniques)

Functional magnetic resonance imaging (fMRI) Detects increases in blood flow and oxygen

metabolism throughout the brain magnetically Yields 3D-computerized pictures of the entire

brain and its active areas Provides most precise information about which

brain regions are specialized for certain capacities and about abnormalities in brain functioning

Positron emission tomography (PET) Depends on X-ray photography, which requires

the injection of a radioactive substance

Functional magnetic resonance imaging (fMRI)

Near-infrared optical topography (NIROT)

NIROT is limited to examining the functioning of the cerebral cortex.

Infrared light is beamed at regions of the cerebral cortex to measure blood flow and oxygen metabolism while the child attends to a stimulus.

Can be used on very young babies as they sit on their parent’s lap.

Psychophysiological Methods

Are powerful tools for uncovering relationships between the brain and psychological development but have some limitations Even though a stimulus produces a consistent

pattern of brain activity, the researcher cannot be certain that an infant has processed the stimulus in a certain way

Many factors can influence a physiological response

Children often do not perform as well as they do outside or without apparatus

Children’s fearful reaction to the equipment affects physiological measures

Clinical/Case Study Method

Brings together a wide range of information on one child Interviews Observations Test scores Psychophysiological

measures

Ethnography and the Study of Culture

Descriptive, qualitative technique

Goal is to understand a culture or social group

Participant Observation Researcher lives in community for

months or years

Benefits and Drawbacks of using Standardized tests

Reliability and Validity

Reliability Consistency,

repeatability of a measure Inter-rater

Different observer have to agree on what they see

Test-retestSame measurement on separate occasions

Validity How accurately the

measure captures the characteristics the researcher is trying to study Internal validity:

study conditions External validity:

generalizability

After choosing research methods, it has to be ensured that the procedures provide trustworthy information

Developmental Psychology

Research DesignsLab 2

General Research Designs

Correlational Design Researchers gather information on individuals,

generally in natural life circumstances, and make no effort to alter their experiences

Then they look at relationships between participants’ characteristics and their behaviour or development

+ examining relationships between variables- no conclusion on cause and effect

Correlation Coefficients

Magnitude Size of the number

between 0 and 1 Closer to one (positive

or negative) is a stronger relationship

Direction Indicated by + or - sign Positive (+): as one

variable increases, so does the other

Negative (-): as one variable increase, the other decreases

Correlations

Examples of Correlation Coefficients

General Research Designs

Experimental Design Researchers assign participants to two or more

treatment conditions Events and behaviours are divided into independent

and dependent variables

+ permits inferences about cause and effect

Independent and Dependent Variables

Independent Experimenter

changes, or manipulates

Expected to cause changes in another variable

Dependent Experimenter

measures, but does not manipulate

Expected to be influenced by the independent variable

An Example of a Laboratory Experiment

The way angry encounters end (independent variable) affects children’s emotional reaction (dependent variable)

Unresolved anger condition vs. resolved anger condition

Anxious facial expressions, freezing in place, seeking of closeness to their mothers

Anger resolution can reduce the stressful impact of adult conflict on children

Modified ExperimentsField Experiment

Use rare opportunities for random assignment in natural settings

Natural Experiment

Quasi-experiment Compare differences in

treatment that already exist

Conditions that cannot be experimentally manipulated for ethical reasons (child maltreatment, premature birth)

Groups chosen to match characteristics as much as possible

An Example of a Natural Experiment Maltreated and non-maltreated

8- to 12-year-olds were enrolled in the same summer camp

Were observed and questioned under similar social conditions

Maltreated children showed more disruptive and aggressive behavoiur and were less cooperative

!Natural experiments cannot achieve the precision and rigour of true experimental research!

Designs for Studying Development

Looking for information about the way participants change over time

Extend correlational and experimental approaches to include measurements at different ages

Longitudinal designs Cross-sectional designs Sequential designs Microgenetic designs

Designs for Studying Development

LongitudinalSame participants studied repeatedly at different ages

Cross-sectional

People differing in age are all studied at the same time

SequentialSame groups of different-aged people studied repeatedly as they change ages

MicrogeneticSame participant studied repeatedly over a short period as they master a task

Longitudinal Design: Advantage

Permits study of common patterns and individual differences in development and relationships between early and later events and behaviours.

Longitudinal Design: Problems

Biased sampling The failure to enlist participants who represent the population of

interest

Selective attrition Participants may drop out for other reasons; the ones who remain are

likely to differ in important ways from the ones who do not continue

Practice effects Performance may improve as a result of repeated testing; better testing

skills, increased familiarity with the test (no developmental factors)

Cohort effects Children developing in the same time period who are influenced by

particular cultural and historical conditions; Results based on one cohort may not apply to children developing at other times

Cross-Sectional Design

Advantages Efficient Not plagued by

selective attrition, practice effects, or theoretical and methodological changes in the field

Problems Does not permit

study of individual developmental trends

Age difference may be distorted because of cohort effects

Sequential Design:Advantages and Problems

When the design includes longitudinal sequences, permits both longitudinal and cross-sectional comparisons

Reveals cohort effects Permits tracking of

age-related changes more effectively than the longitudinal design

May have the same problems as the longitudinal and cross-sectional strategies, but the design itself helps identify difficulties

Example of a Sequential Design 3 cohorts

(1985, 1986, 1987)

3 years longitudinal

Developmental trends across five years

Microgenetic Design Longitudinal designs can describe changes over

years, but cannot capture the processes that produce these changes

Microgenetic designs are an adaptation of the longitudinal approach present children with a novel task and follows their

mastery over a series of closely spaced sessions Within this ‘microcosm’ of development, researchers

observe how change occurs Especially useful for cognitive development (strategies

children use to acquire new knowledge)

Ethical Treatment of Children in Research

Protection from harm Children have the right to be protected from physical and/or psychological

harm

Informed consent Have the right to have explained to them all aspects of the research that

may affect their willingness to participate

Privacy Right to delete their identity on all information collected

Knowledge of results Children have the right to be informed of the results of research

Beneficial treatments Children in control groups have the right to alternative beneficial treatments if

they are available

The Case of Little Albert