chap 2 psychology scientific methods

7/27/2019 Chap 2 Psychology Scientific Methods

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Sept 15

Scientific Principles in Psychology

Scientific Attitudes

Curiosity-ask why, skepticism-show me your evidence, open-mindedness-might there be a

better explanation

Gathering Evidence

Identify question of interest—See/read an event; ask why

Gather information and form hypothesis

o A specific prediction about some phenomenon that often takes the form of an “if -then”

statement

If multiple bystanders are present, then the likelihood that any one bystander

will intervene is reduced

Test hypothesis by Conducting Research-research/experiment will prove the hypothesis

Analyze Data-Draw conclusions between your research and the hypothesis

Build a Body of Knowledge

o Ask further questions—eg. What other factors affect bystander intervention

o Form new hypothesis and test those hypotheses by doing more research

o This allows the scientific process to become self-correcting

Theory

o Broader than hypotheses and psychology theories specify lawful relations between

certain behaviours and their causes

Two Approaches to Understanding Behaviour

Hindsight

Hindsight reasoning can provide valuable insights and is often the foundation on which further

scientific inquiry is build

Related past events can be explained in many creative, reasonable , and contradictory ways

Scientists prefer to test their understanding of “what causes what”

If we understand the causes of a behaviour, the we should be able to predict the conditions for

the future behaviour to occur

If these conditions can be controlled then it the behaviour can be produced

Understanding though prediction and control is a scientific alternative to hindsight

understanding

Theory development is the strongest test of scientific understanding because good theories generate

an integrated network of predictions



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Characteristics of a good theory

Incorporates existing facts and observations within a single broad framework

o Aka. Organizes info. In a meaningful way

Testable

o Generates new hypotheses and predictions whose accuracy can be evaluated bygathering new evidence

Predictions made by theory are supported by the findings of new research

Conforms to law of parsimony

o If 2 theories explain and predict the same phenomena equally well, the simpler theory is

preferred

Defining and Measuring Variables

Variable

o Characteristic or factor that can vary

Eg. Height, hair color

Operational definition

o Defines a variable in terms of the specific procedures used to produce or measure it

o Eg. Stress and academic performance—GPA can be the operational definition

Self reports and reports by others

Self report measures

o Ask people to report on their own knowledge, beliefs, feelings, experiences, or

behaviour

o Often gathered in interviews/questionnaires Participants may be distorted by a social desirability bias

o Tendency to respond in a socially acceptable manner rather than according to how one

truly feels/behaves

Researches can minimize this bias through wording of the question

Measures of Overt Behaviour

Record overt behaviour

o Eg. How many errors a person makes while performing a task during an experiment on

learning

o Eg. Drug effects –measure people’s reaction time—how rapidly they respond to a

stimulus

Coding systems

o Eg. While parent and child jointly performs task, we cold code the parent’s behaviour

into categories like praise child, assists child, and criticizes child

o Observers must know how to use the coding properly so that their measurements will

be reliable—consistent observations



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Humans/ other animals may act differently when they are observed

o Researchers use unobtrusive measures to counter this problem

Disguise their presence and records behaviour

in a way that keeps participants unaware that certain responses are being

measured

Archival Measures

o Records or documents that already exist

o Eg. To evaluate effectiveness of a program to reduce school children’s disruptive

classroom behaviour, researchers examined school records containing student

suspensions/# of trips to office

Psychologists also use tests such as personality tests and IQ tests or neuro-psychological tests—

helps diagnose normal and abnormal brain functioning by measuring how well people perform

mental and physical tasks such as recalling a list of words

Psychologists also record physiological responses to assess what people are experiencing.

Measures of heart rate, blood pressure, respiration rate, hormonal secretions, brain functioning.

These measurements have their own problems because we do not know what they mean.

Methods of Research

Descriptive Research

Seeks to identify how humans and other animals behave –mainly in natural settings

o Provides info about diversity of behaviour and give clues about cause-effect relations

o Case studies, naturalistic observation, surveys are research methods commonly used to

describe behaviour

Case study

In-depth analysis of individual, group, event

Studying cases, researchers hope to find principles of behaviour true for people or general

situations

Data gathered through observation, interviews, psychology tests, physiology recordings, task

performance, archival records

Advantages

o When a rare phenomenon occurs, enables scientists to study it closely

o A case study may challenge the validity of a theory or widely held scientific belief

o Be a source of new ideas and hypotheses that subsequently may be examined by using

more controlled research methods

Limitations

o Poor method for determining cause-effect relations

o May not generalize to other people/situations

To establish generalization of a principle, more case studies/research methods/variety of

cultural groups



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Observers may not be objective in gathering and interpreting data

o Measurement bias/observer bias can occur in any type of research

o Based on an observer’s subjective impressions

o Cases should be followed up by more controlled experiments

Naturalistic Observation

Researcher observes behaviour as it occurs in a natural setting and tries to avoid influencing that

behaviour

Bully ex. 7

Does not permit clear causal conclusions—bias, other variables

Habituation

In chimp example researchers may delay their data collection until participants have habituated

to the observer’s presence

Survey Research: Does your own Personality Match the Canadian National Character

Survey Research

o Info. About topic is obtained through questionnaires/interviews

o Not representative of the population

o Cannot be used to draw cause and effect conclusions

o Relies heavily on participant’s self efforts-can be distorted by the social desirability bias,

interviewer bias, peoples’ inaccurate perceptions of their own behaviour, and

misinterpretation of survey questions

o Unrepresentative samples can lead to faulty generalizations about how an entire

population would respond

Correlation Research: Measuring associations between events

The researcher measures one variable (X)

Measures second variable (Y)

Statistically determines whether X and Y are related

Naturalistic research and surveys do not only describe events but also studies the association

between variables

Correlation does not establish causation

Bidirectionality –two way causality problem

o Both variables have influenced each other

o Spurious-a third variable Z

Correlation coefficient

o Statistic indicates the direction and strength of the relation between two variables



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o Negative correlation occurs when higher scores on one variable=lower scores on the

second variable

Abs value tells you of its strength

Correlation can

o Not establish cause and effect

o Real world association

o Associations that are later studied under controlled lab conditions

o For practical reasons some questions can be studied through experiments and

correlations

o Make predictions

Experiments: Examining Cause and Effect

Experiments have essential characteristics

o Researcher manipulates one of more variables

o Measures whether this manipulation influences other variables

o Attempts to control extraneous factors that might influence the outcome of the

experiment

Logic

o Start with same number of participants

o Treat equally in all respects except for the variable that is of interest

o Isolate this variable and manipulate it

o Measure how groups respond

Independent Variables and Dependent Variables

Independent variable

o Factor manipulated or controlled by experimenter

Dependent variable

o Factor that is measured by the experimenter and may be influenced b the independent

variable

Experimental and Control Groups

Experimental group

o Group that receives a treatment/active level of the independent variable

Control group

o Not exposed to treatment

Provides standard behaviour to which experimental group can be compared

NOTE in experiment the independent variable MUST HAVE at least 2 levels

o Not all experiments need a control group



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Basic ways to Design Experiment

Between groups/subjects design

o Each group in the experiment is composed of a different set of participants

o To draw meaningful conclusions, various groups of participants must be same at the

start of study o Random assignment

Each participant has equal likelihood of being assigned to any one group within

the experiment

Repeated measures/within subjects design

o Each participant is exposed to all the conditions of an independent variable

Counterbalancing- a procedure in which the order of conditions is varied so that no condition has an

overall advantage relative to the others

Manipulating Two independent Variables

Scientists manipulate two/more independent variables simultaneously to study several causal

factors to better capture real life complexity

Manipulating both independent variables –cell phone use and traffic density

o How cell phone use and traffic density each independently influence drivers’

performance

o Whether cell phone use has different effects, depending on whether traffic is heavier or

lighter

o Scientific terms this as an interaction between cellphone use and traffic density

Interaction means that the way in which one independent variable influences the dependent

variable differs depending on the various conditions of another independent variable

Having two independent variables allows for 4 types treatment methods

Threats to the validity of research

Validity

o How well an experimental procedure actually tests what it is designed to test

Internal validity

o Represents the degree to which an experiment supports clear causal conclusions

o Eg. If experiment is well designed and properly conducted, we can be confident that the

independent variable really was the cause of differences in the dependent variable –high internal validity

o Flaws=low internal validity

Confounding variables

Means that two variables are intertwined in such a way that we can not determine which one

has influenced a dependent variable



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Confounding variables prevents one from drawing clear causal conclusions and it ruins the

internal validity of the experiment

Placebo effects

In medical research

o Substance that has no pharmacological effect

Experiment testing

o Placebo-fake dummy

Placebo effect-people receiving a treatment show change in behaviour because of their

expectations not because the treatment itself ha specific benefit

Decrease internal validity by providing alternative explanation for why responses change after

exposure to treatment

Experimenter expectancy effects

Refers to the subtle and unintentional ways researchers influence their participants to

respond in a manner that is consistent with the researcher’s hypothesis

Scientists can take steps to avoid this

o Eg. Researchers who interact with participants in a study/ record participants’ responses

are often kept blind to the hypothesis or the condition that they are assigned which

makes it less likely that these researchers will develop expectations about how

participants “should” behave

o Double blind experiment

Both participant and experimenter are kept blind as to which experimental

condition the participant is in

Minimizes placebo effects and experimenter expectancy effects

Replicating and Generalizing the Findings

External Validity

o The degree to which the results of a study can be generalized to other populations,

settings, and conditions

o Typically judgements about external validity concern the generalizability of underlying

principles

To determine external validity

o Either we/other scientists need to replicate experiment

o Replication is the process of repeating a study to determine whether the original

findings can be duplicated

o If successfully replicated, we become more confident in our conclusion

In typical experiments

o Responses of each participant is analyzed



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o When researchers review a number of experiments that are trying to replicate an effect

they use meta analysis

Statistical procedure for combining results of different studies that examine the

same topic to test the overall significance of the findings

In meta analysis each study is treated as a single participant, and its overall

results are analyzed with those of other studies

Informs researchers about the direction and statistical strength of the

relationships between two variables

The most objective way to integrate the findings of multiple studies and reach

overall conclusions about behaviour

Cross Cultural Replication

o Examining whether findings generalize across different cultures

o Research that fail to replicate may lead to better research and new discoveries as

scientists search for clues to explain why the results were different from one study to

another

o Studies that consistently fail to replicate the original results of earlier research suggests

that the original research was flawed or that the finding was a fluke

o Ultimately the accountability for the results of experiments rests with individual

researchers and the scientific and academic community

Ethical Principles in Human and Animal research

In Canada university research in large is funded by three national government agencies

o The Canadian institutes of Health Research

o Natural Sciences and Engineering Research Council

o Social Sciences and Humanities Research Council Developed tri council policy for ethical conduct for research involving humans

Canadian Psychological Association published Canadian Code of Ethics for Psychologists to cover

behaviour of psychologists engaged in research, direct service, teaching, administration, legal

cases or other roles related to psychology

Psychologists must

o Protect and promote the welfare of participants

o Avoid doing harm to participants

o Not carry out any studies unless the probable benefit is proportionately greater than the

risks

o Provide Informed Consent –explain all aspects of procedure and ensure that theprocedure is understood

Oral/written consent is usually required and assurance is given that one can

withdraw from the study without penalty

For those not able to give informed consent , consent is obtained through

guardians

o Take all reasonable steps to ensure that consent is not given under coercion



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o Ensure privacy and confidentiality

Use of incomplete disclosure/deception

o When participants are misled about the nature of a study

o Supporters of deception research argues that when studying certain types of

behaviours, deception is the only way to obtain natural, spontaneous responses from

participants

o Guidelines permit incomplete disclosure only when no other feasible alternative is

available and when the scientific educational or applied benefits clearly outweigh the

ethical costs of deceiving participants

o If incomplete disclosure is used participants must be debriefed- told the true purpose of

the study at the end of the experiment

o Most psychological studies do not involve incomplete disclosure and deception research

has decreased recently

o In Internet observational studies confidentiality and privacy , informed consent and

debriefing is highlighted

Ethical standards in Animal research

Animals are subjects in 7/8% of psychological studies including research done in wild/controlled

settings

Tell us about human behaviour/behaviour of other species

Canada-fed and CPA code of ethics state experimental animals should not be subjected to pain

stress or privation unless there is no alternative procedure and the research is justified by

prospective scientific/educational benefits

ERBs follow Guide to the care and use of experimental animals

Critical Thinking

Pseudoscientific misinformation:

Ganzfeld procedure

Lots of control-does not replicate it

We need to have a balance of skepticism

chap 2 psychology scientific methods

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