Developmental psychology
Chapter 1
The scope and Methods of Developmental psychology

Introduction

Developmental psychology: the discipline that attempts to describe and explain the changes that occur over time in the thought, behavior, reasoning and functioning of a person due biological, individual and environmental influences.

Studying changes with age

Maturation: aspects of development that are largely under genetic control, and hence largely uninfluenced by environmental factors.

Developmental psychologist study age-related changes in behavior and development.

Age itself causes nothing. So we need to look for the many factors that cause development to take place.

Concepts of human development

The assumptions and ideas we have about human nature will affect how we rear our own children and how we interpret the findings from studies of children.

‘Folk’ theories of development: ideas held about development that are not based upon scientific investigation.
Often reflect the issues that psychologists investigate, with aim of putting our understanding on a firmer, more scientific footing.

Defining development according to world views

The manner in which development is defined, and the areas of development that are of interest to individual researchers, will lead them to use different methods of studying development.

Two paradigms:

Organismic world view

The idea that people are inherently active and continually interacting with the environment, and therefore helping to shape their own development.
Emphasizes the interaction between maturation and experience that leads to the development of new internal, psychological structures for processing environmental input.

Each new stage in development represents an advance on the preceding stage and the individual does not regress to former stages.
Each new stage presents new characteristics not present in the previous stage.

Mechanistic world view

The idea that a person can be represented as being like a machine, which is inherently passive until stimulated by the environment.
Ultimately, human behavior is reducible to the operation of fundamental behavioral units that are acquired in a gradual, cumulative manner.
The frequency of behaviors can increase with age due to various learning processes and they can decrease with age when they no longer have any functional consequence, or lead to negative consequences.
Development is reflected by a more continuous growth function, rather than occurring in qualitatively different stages, and the child is passive rather than active in shaping its own development.
Behaviorists represent this world view.

Ways of studying development

Designs for studying age-related changes

Two general developmental designs

Cross-sectional designs

A study where children of different ages are observed at a single point in time.
Least time-consuming and provides a quick estimate of changes with age.
But: it only describes age differences. Performance is averaged over different individuals at each age.

Longitudinal designs

A study where more than one observation of the same group children is made at different points in their development.
Powerful because each individual’s development is measured over time. It accesses within-person changes with age and between-person differences in age changes.
In many cases the data are summarized by plotting the group average as function of age. But. By looking at each individual’s data, we can determine if there is a gradual change with age or a sudden shift in performance more characteristic of stage-like development.
There are many types of longitudinal designs.
Problems: the cost is very high and they are very time-consuming. It many be difficult to schedule and the drop-out rate can be high. And the possible effects of repeated testing, people can learn.

Cohort: a group of people who were raised in the same environment or who share certain demographic characteristics.

Microgenetic methods

A method that examines change as it occurs and involves individual children being tested repeatedly, typically over a short period of time so that the density of observations is high compared with the typical longitudinal study.
Examine change as it occurs.
Provides detailed information about an individual, or individuals, over a period of transition.

When longitudinal and cross-sectional results tell a different story

Two instances of conflicting results;

• Time between measures
  Sometimes different instances between test ages can result in very different developmental functions.
• Cohort effects
  Changes across generations in the characteristic one is interested in.

Sequential designs

A combination of longitudinal and cross-sectional designs that examines the development of individuals from different age cohorts.
Used to provide a measure of individual differences and reveal whether or not longitudinal and cross-sectional results agree.

Research methods

Observational studies

Studies in which behavior is observed and recorded, and the researcher does not attempt to influence the individual’s natural behavior in any way.
Weaknesses: problems of generalization, observations tend to be unsystematic and in many cases are retrospective, there can be theoretical biases.

Time sampling: an observational study that records an individual’s behavior at frequent intervals of time.

Criticisms:

• the researcher may not get an accurate record of the amount of time spent in different behaviors.
• Many behaviors of interest may simply not occur, or might be missed, during the period that the recording is taking place.

Event sampling: an observational study which records what happens during particular events.

Clinical method: a research method first used by piaget whereby natural behavior is observed and then the individual’s environment is changed in order to understand better the behavior of interest.

Experimental methods

Control an individual’s environment in systematic ways in an attempt to identify which variables influence the behavior of interest.

Psychological tests

Instruments for the quantitative assessment of some psychological attribute or attributes of a person.
Researchers can compare their sample of children against the appropriate norms.

Correlational studies

Studies that examine whether two variables vary systematically in relation to each other.

Two types of correlational studies:

• Concurrent
  Where we are interested in the relationship between variables that are measured at the same time.
• Predictive
  Where we are interested in finding whether individuals retain their relative standing, or rank order, relative to others, over time.

Neurodevelopmental studies
To understand brain development and its relation to developments in perceptual, cognitive, social, and motor skills.

Marker task:
a method designed to elicit a behavior with a known neural basis.

Imaging methods

Methods of recording brain activity.

• Electroencephalogram (EEG): a scalp recording done with electrodes that measure electrical activity produced by neurons.
  Event-related potential (ERP): scalp recordings in which brain activity is monitored during the presentation of specific perceptual events.
• Positron emission tomography (PET): an imaging method measuring cortical activity. Works by measuring blood flow to tissues in the body.
• Functional magnetic resonance imaging (fMRI)

Beyond common sense: the importance of research evidence

Social policy implications of child development research

Social policies: actions, rules and laws aimed at solving social problems or attaining social goals, in particular intended to improve existing conditions.

Developmental researchers have applied their vast store of knowledge to the implementation of social policies.

Developmental functions: growing and changing

Developmental functions: typical trends in development.

• Continuous function, increasing ability
  Behavior that improves with age.
• Continuous function, decreasing ability
• Discontinuous (step) function
• U-shaped functions