PSYB20H3 Chap.1 Defining Development and Research Methods
Defining Development and Research Methods
Start with a precise definition
The opening lecture of PSYB20H3 defines development as systematic change across the lifespan, from conception to death, that typically endures across time and contexts. Two words in that definition do most of the work on tests. Systematic rules out random fluctuation, and enduring rules out a mood or a one-off event.
The lecture then names maturation and learning as the forces behind development and describes development itself as continual, holistic, plastic and shaped by history and culture. Expect multiple-choice items that offer a temporary change and ask whether it counts.
Know what researchers are trying to do
Developmentalists describe, explain and optimize. Description comes in two forms that students often reverse.
Normative description establishes the typical age and pattern for most children, the logic behind milestone charts. Ideographic description follows how one child departs from that pattern, which is why a detailed study of a single child with an unusual profile counts as ideographic.
Explanation asks why development takes the course it does, and optimization uses that knowledge to help children develop well.
Place the three early philosophers
Thomas Hobbes, writing in the early 1600s, held the doctrine of original sin and saw the child as passive and in need of control.
John Locke, in the late 1600s, described the mind as a tabula rasa, a blank slate written on by experience, again with a passive child. Jean-Jacques Rousseau, around 1750, held the doctrine of innate purity and gave the child an active role.
Questions usually describe a parent or a child and ask which philosopher would agree, so learn each doctrine together with the role it assigns to the child.
Separate measures, designs and ethics
Research in the course uses the scientific method: theories describe or explain patterns of behaviour, and hypotheses make testable predictions.
A useful measure must be reliable, giving consistent results, and valid, measuring what it is meant to measure. The lecture compares self-report, observational, case study, ethnographic and psychophysiological measures by their strengths and limitations. Correlational designs ask whether two variables are related, with a coefficient between plus one and minus one, and cannot establish causation.
Experiments manipulate an independent variable, measure a dependent variable, control confounds and use random assignment.
Choose the right age-change design
Three designs track development over time. Cross-sectional studies compare different age groups at one point in time. Longitudinal studies follow the same individuals across years.
Sequential studies follow several age groups across several years, which lets researchers check for cohort effects. Research with children also carries ethical duties: informed consent, the child's own assent, protection from harm, minimal risk, and benefits that outweigh the costs. Term Test #1 covers this lecture, and the cumulative final returns to it, so these distinctions are worth securing early.
What this chapter covers
- 01
Definition of development
- 02
Maturation and learning
- 03
Normative and ideographic description
- 04
Hobbes, Locke and Rousseau
- 05
Reliability and validity
- 06
Correlational and experimental designs
- 07
Cross-sectional, longitudinal and sequential designs
- 08
Ethics with child participants
Worked example · free
Spot the cohort check inside a sequential study
- 1Track each group: the youngest reaches 9 in 2029 and 12 in 2032, while the middle group reaches 12 in 2029.
- 1Age 12 is measured three times: oldest group in 2026, middle group in 2029, youngest group in 2032.
- 1Equal ages in different birth groups let the lab ask whether scores differ because of cohort rather than age.
Key terms
- Maturation
- Maturation is developmental change that unfolds from biological programming rather than from experience.
- Tabula Rasa
- Tabula rasa is Locke's view that the mind begins as a blank slate written on by experience.
- Validity
- Validity is the extent to which a measure assesses what it is intended to measure.
- Cross-Sectional Design
- A cross-sectional design compares different age groups measured at a single point in time.
Defining Development and Research Methods FAQ
How is development defined in this course?
Development is the set of systematic changes across the lifespan, from conception to death, that typically last across time and settings. The definition excludes brief or random changes, such as a single bad day, and includes lasting shifts in physical, cognitive and social functioning that a researcher could observe again later.
What is the difference between normative and ideographic development?
Normative description identifies the typical pattern and timing shared by most children of an age, as in milestone charts. Ideographic description focuses on how a particular child differs from that typical pattern. A detailed study of one child's unusual path is ideographic even though it may later inform normative research.
Can a correlational study show that one variable causes another?
No. A correlation shows only that two variables are related, positively or negatively, with a coefficient between plus one and minus one. A third factor or a reversed direction could explain the link. Establishing cause requires an experiment that manipulates the independent variable and randomly assigns participants to conditions.
What ethical protections apply to research with children?
Parents provide informed consent and children give their own agreement, called assent. Researchers must protect participants from harm, keep risk minimal and ensure that the benefits of the research outweigh its costs. These protections apply whatever design or measure the study uses.
Exam move
Make a two-column sheet: one column of terms from this lecture and one column of short scenarios you invent. Cover the terms and classify each scenario, then explain the deciding feature aloud. Redo the designs with new ages and years until you can tell cross-sectional, longitudinal and sequential apart in under ten seconds.
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