Developmental%20Psychology:%20Research%20Issues

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• Developmental Psychology Research Issues
• Intractable Variables
• Difficult or impossible to manipulate
• Heredity/Genes
• Environment
• Age
• Age is a proxy for causal variablesi.e., age
  co-varies with these causal agents, but it is not
  a causal variable

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• Measurement Equivalence
• When constructs change with development, measures
  that are appropriate at one age (time) may be
  inappropriate at another age
• Ex Assessment of attachment in preschoolers
• Is a separation-reunion procedure appropriate?

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• Self-report data are limited
• Parents, teachers, and other adults often
  complete self-report measures of childrens
  behavior
• Greater reliance on observational techniques
• Inferring the meaning of behavior is difficult
• Ex Infants understanding of object permanence

4

• Complexity of causal influences
• Ethical concerns preclude manipulation of many
  variables
• Ex maltreatment and childrens development
• Laboratory analog studies may compromise external
  validity
• Ex Marital conflict and childrens development

5

• Direction of causation
• Biases/assumptions about the direction of
  influence
• Ex parents influence children rather than the
  reverse
• Bidirectional influences are more likely than
  unidirectional influences

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• General Research Designs
• Experimental Designs
• Manipulation of hypothesized independent variable
• Random assignment of participants to different
  conditions (between-subjects designs) OR other
  control procedures (within-subjects designs,
  small-n designs)
• Allow strong inferences about causal relationships

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• Potential Limitations of Experimental Designs
• Participant non-compliance in the treatment or
  intervention condition (e.g., dropping out,
  failure to participate fully in the treatment)
• Generalization (external validity)

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• Non-experimental (Correlational) Designs
• No manipulation of variables
• No random assignment or other comparable control
  procedures
• Not possible to make strong causal inferences

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• Why not?
• Selection Bias (Confounding Variables)
• Refers to third variables that are correlated
  with both the predictor variable and the outcome
  variable
• Ex Does high-quality child care cause improved
  school readiness?
• Children in high-quality child care (and their
  families) are likely to be different in many ways
  from children in lower-quality child care
  (socioeconomic status high-quality parental
  care)
• These confounding variables are likely to be
  related to school readiness

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• Most common approach to reducing selection bias
• Identify, measure, and control for possible
  confounding variables either in the research
  design or in the statistical analysis

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• Developmental Designs
• Designs in which age-related change is examined
• Normative development (developmental functions)
• Individual differences

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• Variables Involved in Developmental Designs
• Cohort Groups of participants who are born or
  experience some other common event in the same
  time period
• Ex children born in 1980 are a cohort
  individuals growing up during the Great
  Depression are also a cohort
• Age
• Time/Point of Assessment

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• Simple Developmental Designs
• Longitudinal Designs
• A single cohort is examined at multiple ages (and
  thus at multiple times of assessment)
• Age and time of assessment are confounded
• An event may occur between points of assessment
  that produces differences in the dependent
  variable
• Ex Sept. 11 may affect rates of psychological
  disorders in children
• If we see increases in psychological disorders in
  a longitudinal design, are they due to age or to
  time of assessment differences?

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• Advantages
• Can examine stability and change in individual
  childrens characteristics and behavior over time

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• Disadvantages
• Non-random participant loss (selective attrition)
• Participants who finish the study differ in
  systematic ways from participants who drop out
• Final sample is not representative of the group
  (population) researcher wanted to studyfindings
  may not generalize
• Practice effects
• Change due to familiarity with data collection
  procedures rather than change due to development

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• Time-consuming and expensive

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• Cross-sectional Designs
• Multiple cohorts (and multiple ages) are examined
  at a single time of assessment
• Cohort and age are confounded
• Differences across cohorts may produce changes in
  the dependent variable
• Ex Cohorts born in 1970 and 1990 are likely to
  differ with respect to early child care
  experiences
• If we see differences in social competence in a
  cross-sectional design, are they due to age or to
  cohort differences?

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• Advantages
• More efficient than a longitudinal design
  (faster, less expensive)
• No participant loss
• No practice effects

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• Disadvantages
• Cannot examine stability or change in individual
  childrens characteristics or behavior over time

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• Complex Developmental Designs
• (Sequential Designs)
• Involve complete crossing of 2 of 3 variables
  (cohort, age, time of assessment)
• Interpretation of data from these designs is
  still ambiguous
• Results cannot be clearly attributed to one of
  the three variables (confounding is still
  present)

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• Baltes (1968) argued for the use of the
  cohort-sequential design in studies of
  development
• Allows for the separation of cohort and age
  effects
• But time of assessment is still confounded with
  both factors
• Baltes argues that time of assessment is unlikely
  to affect data in developmental studies

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• Cohort-sequential design
• Different cohorts compared at the same ages (but
  at different times of assessment)

Cohort Time of Assessment 1975 1980 1985 Time of Assessment 1975 1980 1985 Time of Assessment 1975 1980 1985
1960 15 20
1965 15 20
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• Allows comparison of children of the same age
  from different cohorts
• Ex Two groups of 15-year-olds (different
  cohorts) two groups of 20-year-olds (different
  cohorts)
• If the same-age groups are different from one
  another with respect to the dependent
  variable(s), have evidence for cohort effects
• If not, can attribute any differences to age
  rather than to cohort
• But both are confounded with time of assessment

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• Data Collection Techniques
•  Systematic Observation (2 Types)
• Naturalistic Observation
• Observe childs behavior in a natural environment
• Exs playground, school, home

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• Structured Observation
• Design a situation that will elicit relevant
  behavior(s)
• Typically conducted in a laboratory setting (but
  not always)
• Observe different children in the same situation

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• Coding Observational Data
• Event sampling Every occurrence of a
  behavior(s) during a specified observation period
  is recorded
• Time sampling The observation period is divided
  into intervals and the occurrence of a
  behavior(s) is recorded if it occurs during an
  interval the same behavior is not coded twice in
  the same interval
• Likely to under- or over-estimate the frequency
  of behaviors depending on the base rate of the
  behavior and the size of the interval

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• Ratings Likert-type scales are used to rate
  behavior(s) during a specified observation period
• Often used for molar behaviors (e.g., maternal
  sensitivity)
• Typically require a higher level of inference on
  the part of observers

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• General Disadvantages (Observation)
• Observer Bias
• Observer records/judges behavior inaccurately in
  order to make it consistent with hypotheses or
  with other beliefs (unintentional!)
• Participant Reactivity
• Observers presence affects behavior of those
  being observed

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• Self-report Measures
• Clinical Interviews
• More open-ended questionsresponse choices are
  not limited
• Participants may be asked different questions
  (depending on their answers)

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• Structured interviews and questionnaires
• More close-ended questionsresponse choices are
  limited
• Ex yes/no questions, rating scales, multiple
  choice questions
• All participants are asked the same questions

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• Parents, child care providers, and teachers often
  provide information about infants and younger
  children
• Ex infant/child temperament behavior problems
  social skills

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• General Disadvantage (self-report or report by
  others)
• Data may be inaccurate due to
• Deliberate (or semi-deliberate) deception
• Misinterpretations of questions
• Lower verbal skills
• Memory limitations
• Lower observational skills
• Less knowledge about relevant behaviors

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• Psychophysiological Methods
• Record physiological responses
• Exs heart rate, hormone levels (cortisol),
  brain wave activity
• Infer psychological states from these responses
  (e.g., perceptions, emotions)

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• Advantage
• Can be used with preverbal infants and young
  children (limited language)
• Disadvantage
• Changes in physiological responses can be caused
  by many irrelevant factors (e.g., hunger,
  boredom, movement)