Child Development Laura E. Berk 8th edition

Chapter 2Research Strategies

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HypothesisResearch can:Test a prediction of one theory against that of anotherTest a prediction of one theoryStart with a research question, if there is no theoryA prediction often drawn from a theory.

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Why Should We Learn About Research Strategies? Helps us separate dependable information from misleading results. Individuals who work with children may be in a unique position to build bridges between research and practice. Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Systematic ObservationNaturalistic ObservationIn the field, or natural environment, where behavior happens

Structured ObservationsLaboratory situation set up to evoke behavior of interestAll participants have equal chance to display behavior

Naturalistic or Structured observation?

Marshmallow Experiment

Collecting Systematic ObservationsEvent SamplingObserver records all instances of a particular behavior during a specific time period.Time SamplingObserver records whether certain behaviors occur during a sample of short time intervals.Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Limitations of Systematic ObservationObserver InfluenceParticipants may react in unnatural ways.Can be minimizedObserver BiasObservers record what they expect, rather than what really happens.Corbis Royalty FreeCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

InterviewsUnstructured Clinical InterviewFlexible, conversational styleProbes for participants point of viewStructured InterviewEach participant is asked same questions in same wayMay use questionnaires; get answers from groupsCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Limitations ofClinical InterviewsAccuracy of participants expressionsDistortions in participantsRecallJudgmentsFlexibility may make responses too varied to compare btw samples/studiesPhotodiscCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Psychophysiological MethodsMeasures of autonomic nervous system activityHeart rate, blood pressure, respiration, pupils, stress hormonesCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon. www.adinstruments.com/

Methods of Measuring Brain Functioning Electroencephalogram (EEG)Event-related potentials (ERPs)Functional magnetic resonance imaging (fMRI)Position emission tomography (PET)Near-infrared optical topography (NIROT)Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Functional magnetic resonance imaging (fMRI)Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon. AP/Wide World Photos Scott K. Holland

Near-infrared optical topography (NIROT)NIROT is limited to examining the functioning of the cerebral cortex. Can be used on very young babies as they sit on their parents lap. Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon. Courtesy of Gentaro Taga, University of Tokyo

Memory Impairments in Infants of Diabetic Mothers: Findings of ERP ResearchERPs to assess young infants memory performance showed a diabetic pregnancy places the fetus at risk for lasting memory deficits as a result of iron depletion in critical brain areas. Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

ERPs recorded over the left temporal lobe as 8-month old infants of diabetic mothers and controls viewed familiar and novel objects. Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Effects of Diabetes during pregnancy Mothers excess blood glucoseFetus gets overfed Higher level of insulin in fetus to metabolize maternal glucose Higher demand for oxygenIncreased production of red blood cells to get oxygenProduction of red blood cells need iron taken from its own iron stores Iron depletion interferes with brain growthSmaller hippocampus

Clinical/Case Study MethodBrings together a wide range of information on one childInterviewsObservationsTest scoresPsychophysiological measuresFamily Life Royalty Free CDCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

EthnographyDescriptive, qualitative techniqueGoal is to understand a culture or social groupParticipant ObservationResearcher lives in community for months or yearsPhotodiscCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Reliability and ValidityReliabilityConsistency, repeatability of a measureInter-raterTest-retestValidityHow accurately the measure captures the characteristics the researcher is trying to studyInternal validity: study conditionsExternal validity: generalizabilityCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Correlation CoefficientsMagnitudeSize of the number between 0 and 1Closer to one (positive or negative) is a stronger relationshipDirectionIndicated by + or - signPositive (+): as one variable increases, so does the otherNegative (-): as one variable increase, the other decreasesCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Correlation coefficients can range from 1.00 to +1.00. 1.00 means that two variables are perfectly correlated in a positive direction. 0 means that two variables are not correlated1.00 means that two variables are perfectly correlated in a negative direction

Examples of Correlation CoefficientsCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Independent and Dependent VariablesIndependentExperimenter changes, or manipulatesExpected to cause changes in another variableDependentExperimenter measures, but does not manipulateExpected to be influenced by the independent variableCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

An Example of a Laboratory ExperimentCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Avoiding Confounding VariablesRandom AssignmentResearchers use unbiased procedure to assign participants to treatment conditionsSometimes combined with matching participants on key characteristicsPhotodiscCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Modified ExperimentsField ExperimentUse rare opportunities for random assignment in natural settingsNatural ExperimentQuasi-experimentCompare differences in treatment that already existGroups chosen to match characteristics as much as possibleCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

An Example of a Natural Experiment Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Can Musical Experiences Enhance Intelligence? Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Designs for Studying DevelopmentCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

LongitudinalSame participants studied repeatedly at different agesCross-sectionalPeople of differing ages all studied at the same timeSequentialSame groups of different-aged people studied repeatedly as they change agesMicrogeneticSame participant studied repeatedly over a short period as they master a task

Longitudinal Design AdvantagesPermits study of common patterns and individual differences in development and relationships between early and later events and behaviors.ProblemsAge-related changes may be distorted because of biased sampling, selective attrition, practice effects, and cohort effects.Theoretical and methodological changes in the field can make findings obsolete.Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Cross-Sectional Design AdvantagesEfficient Not plagued by selective attrition, practice effects, or theoretical and methodological changes in the fieldProblems Does not permit study of individual developmental trendsAge difference may be distorted because of cohort effectsCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Sequential Design 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 designMay have the same problems as the longitudinal and cross-sectional strategies, but the design itself helps identify difficultiesCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Example of a Sequential DesignCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Microgenetic Design Offers insights into how change occursRequires intensive study of participants moment-by-moment behaviors The time required for participants to change is difficult to anticipatePractice effects may distort developmental trends

Copyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Childrens Research RightsProtection from harmInformed consentPrivacyKnowledge of resultsBeneficial treatmentsCorbis Royalty FreeCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

Childrens Research Risks Age Differences Childrens Unique Characteristics Corbis Royalty FreeCopyright 2009 Pearson Education, Inc. Publishing as Allyn & Bacon.

********Figure 2.1 Functional magnetic resonance imaging (fMRI) This 6-year-old is part of a study that uses fMRI to find out how his brain processes light and motion. The fMRI image shows which areas of the boys brain are active while he views changing visual stimuli.*Figure 2.2 Near-infrared optical topography (NIROT).*Figure 2.3 ERPs recorded over the left temporal lobe as 8-month old infants of diabetic mothers and controls viewed familiar (vide taped image of mother) and novel objects. ***** *Figure 2.5 - A positive and a negative correlation.**Figure 2.6 Does the way adults end their angry encounters affect childrens emotional reactions? ***Figure 2.7 A natural, or quasi-, experiment on the relationship of child maltreatment to childrens social adjustment. Researchers brought children to a summer camp to observe them under similar condition. One group had a hx to maltreatment and the other had none. Peers consistently rated maltreated children as more disruptive, aggressive, and less cooperative (Shields et al., 2001)*Figure 2.8 Sustained music lessons promote small gains in intelligence.**Figure 2.9 Example of a Sequential Design. Three cohorts, born in 1985 (blue),1986 (pink), and 1987 (green),respectively, are followed longitudinally for three years. Testing the cohorts in overlapping grades enables researchers to check for cohort effects by comparing participants born in different years when they reach the same grade (see diagonals). In a study using this design, same-grade adolescents who were members of different cohorts scored similarly on a questionnaireassessing family harmony, indicating no cohort effects. By following each cohort for just three years, the investigator could infer a developmental trend across five years, from sixth to tenth grade. *