CHILD PSYCHOLOGY Second Canadian Edition Vasta, Younger, Adler, Miller, Ellis Prepared by: Mowei Liu

Chapter 2 Research Methods

Learning Objectives Learning Objective 2.1 Understand how researchers use the scientific method to study child development.Learning Objective 2.1 Understand how researchers use the scientific method to study child development. Learning Objective 2.2 Compare and contrast the research methods commonly used to study children.Learning Objective 2.2 Compare and contrast the research methods commonly used to study children. Learning Objective 2.3 Analyze the strengths and limitations of the four basic methods for studying child development as a process.Learning Objective 2.3 Analyze the strengths and limitations of the four basic methods for studying child development as a process.

Learning Objectives Learning Objective 2.4 Understand the uses of cultural research, comparative research, and psychophysiological methods.Learning Objective 2.4 Understand the uses of cultural research, comparative research, and psychophysiological methods. Learning Objective 2.5 Explain the ethical guidelines for human research that developmental researchers must follow.Learning Objective 2.5 Explain the ethical guidelines for human research that developmental researchers must follow.

Scientific Research Scientific method: rules for designing, conducting, evaluating, and communicating researchScientific method: rules for designing, conducting, evaluating, and communicating research –Theory: a set of statements that describe a relation between behaviour and the factors that influence that behaviour –Hypothesis: a statement as to how one variable(s) may influence another variable(s) High temperature conditions enhance aggressionHigh temperature conditions enhance aggression –Law (Principle): a proven statement supported by strong evidence Responses that produce satisfying consequences are strengthened (Law of Effect)Responses that produce satisfying consequences are strengthened (Law of Effect)

Objectivity and Measurement The scientific method assumes objective measurementThe scientific method assumes objective measurement –Serves to eliminate bias –Aims to operationalize the methods of study so that other scientists can replicate the study (and presumably replicate the research findings) Objectivity can be achieved byObjectivity can be achieved by –A focus on observable behaviours –Ensuring that the behaviours under study are precisely defined and are measurable –Using a quantitative approach to measurement

Descriptive research consists of conducting observations or interviews and recording responsesDescriptive research consists of conducting observations or interviews and recording responses Correlational research aims to describe the association between two variablesCorrelational research aims to describe the association between two variables Experimental research aims to show a causal relationship between one variable and anotherExperimental research aims to show a causal relationship between one variable and another Types of Research

Descriptive Research Observational methodsObservational methods –Naturalistic observations vs. structured observations –Limitations Observer bias: the influence of the observer’s expectations and interpretationsObserver bias: the influence of the observer’s expectations and interpretations Observer influences: the effects of the observer’s presenceObserver influences: the effects of the observer’s presence

Descriptive Research Interview methodsInterview methods –Open-ended vs. structured –Can provide a wealth of information –Rely on the informant’s knowledge, memory and ability or willingness to communicate Case studiesCase studies –Bring a wide range of information on one child –Often are concerned with clinical issues –Cautions need to be made when drawing conclusions

Correlational Research A variable is any factor that can take on different valuesA variable is any factor that can take on different values –E.g. running speed, intelligence quotients, gender A correlation is a statistical statement as to the degree and direction of relationship between two variablesA correlation is a statistical statement as to the degree and direction of relationship between two variables –Positive: Values of one variable change in the same direction (increase or decrease) as the other variable –Negative: High values of one variable are associated with low values of the other variable

Correlational Research The correlational coefficient “ r ” reflects the direction and strength of a relation between two variablesThe correlational coefficient “ r ” reflects the direction and strength of a relation between two variables –Ranges from -1 through 0 through +1 –Negative values reflect a negative relation –Positive values reflect a positive relation –The strength of the relation is indicated by the size of the number: 0.5 is less strong than is 0.99 Correlations do not prove causality

Figure 2.1 Scatter diagrams illustrating correlations between two variables. Each dot represents one child and shows the child’s values for the two variables. One value is plotted from the vertical axis and the other from the horizontal axis. The left two graphs show positive correlations, and the right two graphs show negative correlations. Correlational Research

A high positive r (0.78) does not imply that watching Sesame Street causes improved reading – only that the two variables are relatedA high positive r (0.78) does not imply that watching Sesame Street causes improved reading – only that the two variables are related Suggests the need for an experimentSuggests the need for an experiment Correlational Research: Example Figure 2.2 A scatter diagram of a hypothetical correlation between children’s viewing of Sesame Street and their reading level. The correlation coefficient ( r ) shows a strong positive relation between the two variables.

Experimental Research Experiments offer the opportunity to prove causality, i.e., manipulation of one variable induces change in another variableExperiments offer the opportunity to prove causality, i.e., manipulation of one variable induces change in another variable Variables in an experiment:Variables in an experiment: –Independent variable (IV) is manipulated by the experimenter and is assumed to be a causal factor –Dependent variable (DV) is measured by the experimenter and is assumed to be controlled by the IV

Hypothesis: Watching Sesame Street improves reading abilityHypothesis: Watching Sesame Street improves reading ability IV: Hours of watchingIV: Hours of watching DV: Reading level test scoresDV: Reading level test scores Four groups are asked to watch either 2, 4, 8, or 10 hours per weekFour groups are asked to watch either 2, 4, 8, or 10 hours per week Results: Increases in viewing time lead to increases in reading levelResults: Increases in viewing time lead to increases in reading level Experimental Research: An Example of a Group Study Figure 2.3 Sesame Street Viewing and Reading Test Performance. Each bar shows the average test score for all the children in that experimental group. What do these results indicate about the relation between Sesame Street viewing and reading ability? Why can we say from these findings that viewing Sesame Street improves reading ability?

Experimental Research: Other Experimental Designs Sometimes a group is not available for a studySometimes a group is not available for a study –Study can be conducted using one subject –Reversal Replication Design involves measuring the DV under a baseline condition (phase A), instituting the IV (Phase B), reverting back to the baseline (Phase A), and then giving the IV to the subject a second time (Phase B) A B A BA B A B Sometimes treatment CANNOT be reverted or withdrawnSometimes treatment CANNOT be reverted or withdrawn

Reversal-Replication Design Figure 2.4 A reversal-replication design showing a causal relation between the presence of mother (the independent variable) and the amount an infant smiles (the dependent variable). The third and fourth phases replicate the procedures and results of the first two phases.

Sometimes variables can not be experimentally manipulatedSometimes variables can not be experimentally manipulated –Ethical concerns –The nature of some independent variables (such as cultural background) –Quasi-experimental studies allow researchers to compare groups differing on some important characteristics Experimental Research: Other Experimental Designs

Studying Development Longitudinal studies measure a behaviour in the same subject or group at different agesLongitudinal studies measure a behaviour in the same subject or group at different ages Advantages of longitudinal designs:Advantages of longitudinal designs: –Provide estimates of stability of behaviour over time –Estimate the impact of early experiences on later behaviour Issues in longitudinal designs:Issues in longitudinal designs: –Attrition of subjects over time –Problems with repeated testing –Measurement instruments become outdated

Studying Development Cross-sectional studies measure a behaviour in different aged subjects at the same point in timeCross-sectional studies measure a behaviour in different aged subjects at the same point in time –Cross-sectional studies cannot tap into stability of behaviour (because different subjects are used) –Cohort effect: Different age groups have different life experiences that may have a profound impact on their behaviour Cross-sequential studies combine longitudinal and cross-sectional designsCross-sequential studies combine longitudinal and cross-sectional designs –Costly and time consuming

A Cross-Sequential Design FIGURE 2.5 A cross-sequential design. Children aged 4, 7, and 10 years are compared cross-sectionally at Time 1 to reveal age differences. Three years later, at Time 2, another cross-sectional design is conducted comparing these children who are now aged 7, 10, and 13. How might cohort effects play a role in any differences found? To examine the stability of competitiveness, each of the three groups is examined longitudinally comparing their scores at Time 2 to those at Time 1. How could repeated testing affect the results? Comparing the groups who were 7 and 10 at Time 1 with those who are 7 and 10 at Time 2 allows the researcher to examine for a cohort effect or a repeated testing effect.

Studying Development Microgenetic studies examine developmental changes as they are occurMicrogenetic studies examine developmental changes as they are occur Studies small numbers of children and administers repeated measures at the time the developmental change is expected to occurStudies small numbers of children and administers repeated measures at the time the developmental change is expected to occur –Costly –Repeated assessment itself may cause change

Other Research Tactics Cross-cultural research examines a behaviour under different cultural conditions, testing the behaviour’s universalityCross-cultural research examines a behaviour under different cultural conditions, testing the behaviour’s universality Comparative research examines a behaviour in non-humansComparative research examines a behaviour in non-humans –Avoids some ethical issues by doing research with animals Effects of social isolation on maternal behaviourEffects of social isolation on maternal behaviour Psychophysiological methods examine physiological activities associated with the presentation of stimuli.Psychophysiological methods examine physiological activities associated with the presentation of stimuli.

Ethical Issues Research studies must be conducted to avoidResearch studies must be conducted to avoid –Physical or psychological injury –Violations of privacy Through the use of peer reviews, subjects are ensured ofThrough the use of peer reviews, subjects are ensured of –Informed consent –Debriefing –Anonymity and confidentiality Research conducted with animals must also carefully follow ethical guidelinesResearch conducted with animals must also carefully follow ethical guidelines

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