EXPERIMENTAL PSYCHOLOGY AND THE SCIENTIFIC METHOD

Psy105 - Experimental Psychology Chapter 1

CHAPTER OBJECTIVES Understand why we rely on scientific

methods rather than common sense to explain.

Learn the principles of the scientific method Learn the basic tools of psychological

research Understand how “cause and effect” is

established by experimentation

PSYCHOLOGY IS A SCIENCE! Science = Content and Process Psychology is the science of behavior, thus it

relies on scientific methodology and techniques in gathering data about, and analyzing behavior.

These processes vary form surveys, to therapy sessions, to laboratory experimentations

Aside from science, where do we get knowledge from?

Philosophy Folk wisdom Common sense

WHY SCIENTIFIC METHODOLOGY? Because commonsense, though very useful,

is not enough. Limitations of commonsense:

Contradicting at times Gathered from small samples of behavior Might be biased Generally unreliable

WHERE DO COMMONSENSE KNOWLEDGE COME FROM?

Seemingly credible and trustworthy sources People we like, respect, or admire Our own observations and interaction with

others

Upon believing something, we tend to notice things that confirm our beliefs more than those that disconfirm it.

NONSCIENTIFIC INFERENCES Traits, traits, traits

Ay nadapa…Lampa! Stereotyping

Basta kulot…. Poor calculations of the probability

Na-fi-feel ko…tatama tayo sa Lotto! Overconfidence bias

I’m super sure!

CHARACTERISTICS OF MODERN SCIENCE

THE SCIENTIFIC MENTALITY Behavior must follow a natural order;

therefore, it can be predicted. Faith in an organized universe is essential to

science. Determinism

GATHERING EMPIRICAL DATA Describing the Universe’s order requires

collecting empirical data – data that are observable or experienced.

SEEKING GENERAL PRINCIPLES Data gathered should be organized through

principles, such as laws or theories. Theories pull together or unify diverse sets of

scientific facts into an organizing theme.

GOOD THINKING Collection and interpretation of date should

be systematic, objective, and rational. Openness to new ideas Follow the rules of logic Parsimony – When 2 explanations are

equally defensible, the simplest explanation is preferred until it is ruled out by conflicting data.

SELF-CORRECTION Acceptance of the uncertainty conclusions Change is an important part of scientific

progress Theories are best tested through attempts at

falsification, not verification Modus tollens – we can never really prove

that a statement is true, we can only prove that it is false.

PUBLISHING RESULTS Science has become a highly public activity Continuous exchange of information and

incorporation of findings is vital to the scientific process

REPLICATION We should be able to repeat our procedures

and get the same result. It gives us more confidence in our findings.

OBJECTIVES OF PSYCHOLOGICAL SCIENCE (SCIENTIFIC METHOD)

DESCRIPTION The initial step Information about what the behavior is like Systematic and unbiased account of the

observed characteristics of behaviors

PREDICTION The capability of knowing in advance when a

certain behavior would be expected to occur, because we have identified other conditions with which the behavior is linked or associated.

EXPLANATION To be able to understand what caused a

behavior. Knowledge of the conditions that produced

the behavior.

CONTROL Application of what has been learned about

the behavior Use of knowledge to effect change or

improve behavior Applied research

TOOLS OF PSYCHOLOGICAL SCIENCE

OBSERVATION Systematic noting and recording of events Events that are observable, or at least their

observable signs This system should be used consistently in

any given research Must be objective

MEASUREMENT The assignment of numerical values to

observed objects or events according to conventional rules

Should also be used consitently

EXPERIMENTATION Undertaken to test a testable prediction – a

Hypothesis How a particular behavioral event will occur

in certain, specifiable situations Involves manipulation of a setting

SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE

THE ANTECEDENT CONDITION Explanation = specifying the antecedent

conditions of an event or behavior Circumstances that come before the event or

behavior

XYZ Helping XYZ ? XYD ?

COMPARING TREATMENT CONDITIONS Treatments – Manipulated specific sets of

antecedent conditions Different groups of participants are exposed

to different treatments so as to compare the effects of varying antecedents

THE PSYCHOLOGY EXPERIMENT A controlled procedure in which at least two

different treatment conditions are applied to two identical groups of subjects.

The resulting behaviors are them measured and compared to test the hypothesis about the effects of the treatment conditions

Careful control; other explanations should be ruled out.

THE PSYCHOLOGY EXPERIMENT

Treatment 1(Hypothesiz

ed Antecedent)

Group 2Group 1

Treatment 2(A Neutral

Antecedent)

Behavior Behavior

THE PSYCHOLOGY EXPERIMENT

Independent Variable

Dependent Variable

Control Group

Experimental Group

ESTABLISHING CAUSE AND EFFECT Only true experiment allows us to make

causal statements Temporal relationship – a time difference

holds in the relationship; the cause precede the effect

ACTIVITY Hypothetically design a simple experiment Should be:

Psychological Testable/feasible Variables are measurable Ethical

ACTIVITY Present the following:

Your educated guess Observational or theoretical basis for the guess Characteristics of the sample Treatment Conditions (IV and neutral) Behavior or event to be measured (DV) Diagram