The Science of Psychology Psychology: A Concise Introduction 2 nd Edition Richard Griggs Chapter 1 Prepared by J. W. Taylor V.

The Science of Psychology

Psychology: A Concise Introduction

2nd Edition

Richard Griggs

Chapter 1

Prepared byJ. W. Taylor V

Psychology

The science of behavior and mental processes

Psychologists attempt to understand1. Observable behavior: Such as speech and

physical movement

2. Mental processes: Such as remembering and thinking, which cannot be directly observed

The Journey…

The Four Major Research Perspectives

Research Methods Used by Psychologists

How to Understand Research Results

The Four Major Research Perspectives

Research Methods Used by Psychologists

How to Understand Research Results

The Four Major Research Perspectives

Perspectives Emphasizing Internal Factors

Perspectives Emphasizing External Factors

Four Perspectives

All four perspectives are complementary; they fit together like the pieces of a jigsaw puzzle to give us the complete picture.

No one perspective is “better’ than another, as each one provides information of behavior and mental processing.

All four perspectives are complementary; they fit together like the pieces of a jigsaw puzzle to give us the complete picture.

No one perspective is “better’ than another, as each one provides information of behavior and mental processing.

BiologicalBiological

CognitiveCognitive

BehavioralBehavioral

Socio-cultural

Socio-cultural

Perspectives Emphasizing Internal Factors

Biological perspective Views our physiological hardware (especially

the brain and nervous system) as the major determinants of behavior and mental processing

Cognitive perspective Emphasizes how our

mental processes, such as perception, memory, and problem solving, work and impact our behavior

The Biological Perspective

There are many reasons why people get depressed From a biological perspective, we would focus on a

deficiency of activity for certain chemicals in our nervous system as the cause of this disorder, and use anti-depressant drugs to alleviate the disorder

A few weeks after starting to ingest the drugs, we feel better because mood is in part a function of brain chemistry

The Biological Perspective

Biological psychologists also study the involvement of the various parts of the brain and nervous system on our behavior and mental processing

For instance, vision is actually processed in the back of our heads (hence, we really do have eyes in the back of our heads,” or more precisely “the back of our brains”)

The Cognitive Perspective

When explaining why people become depressed, the cognitive psychology would focus on reasons such as how people explain their successes and failures If we blame ourselves for all of our setbacks (i.e., make

internal attributions), we might start to feel poorly about ourselves

However, if we realize the situation played a role in some of our setbacks (i.e., make external attributions), we might not feel so badly Of course, it is important for students not to blame their

academic failures on their teachers, because in so doing they would fail to take personal responsibility for their lives!

The Cognitive Perspective

Many people report problems remembering other people’s names Often, we claim it is because we have bad

memories, but is that so? Or, is it that we never bothered to exert the

mental energy required in the first place to encode other people’s names?

Both explanations may have validity, and such explanations would be of interest to a cognitive psychologist

Perspectives Emphasizing External Factors

Behavioral perspective Explains that we behave as we do because of

our past history of conditioning by our environment

Sociocultural perspective Focuses on the impact of other people and

culture on our behavior and mental processing

Behavioral Perspective

Two types of conditioning:

ClassicalConditioning

ClassicalConditioning

OperantConditioning

OperantConditioning

Can explain how we learn fear and other emotional responses, taste aversions, and certain other behaviors

Involves the relationship between our behavior and its environmental consequences

Classical Conditioning

When entering a department store, you may catch the scent of a perfume or cologne of an old boyfriend or girlfriend, and instantly be reminded of that person because during the relationship, you came to associate the scent with the person

Operant Conditioning

If you ask a question in class, and the teacher say “What a stupid question!” you are unlikely to ask questions in the future to avoid such an undesirable consequence

But, if the teachers prefaces his or her response to the question with “That’s an interesting question,” you may continue to ask questions in the future because of the desirable consequence of being implicitly told you are smart

The Sociocultural Perspective

In 1964, Kitty Genovese was brutally attacked and murdered while trying to enter her apartment building in New York City late one night. Many of the people living in the building heard her screams and cries for help, but no one called the police under after the attacker had killed her and fled more than 30 minutes later.

Subsequently, researchers devised laboratory experiments that examined how particular variables influence people’s decision whether or not to help each other.

Major Research Perspectivesin Psychology

Perspective Major Explanatory Focus

Biological How our physiology (especially the brain and nervous system) produces our behavior and mental processes and how genetics and evolution have impacted our physiology

Cognitive How our mental processes, such as perception, memory, and problem solving, work and how they impact our behavior

Behavioral How external environmental events condition our observable behavior

Sociocultural How other people and the cultural context impact our behavior and mental processes

Research Methods Used by Psychologists

Descriptive Methods

Correlational Studies

Experimental Research

Research Methods

Descriptive

Correlational

Experimental

Descriptive Methods

Include Observational techniques Case studies Survey research

Seek to provide objective and detailed descriptions of behavior and mental processes

Descriptive Methods:Observational Techniques

The researcher directly observes the behavior of interest Naturalistic observation: The behavior being

observed occurs in its natural setting, without the researcher intervening in the behavior being observed.

Participant observation: The observer becomes part of the group being observed. This type of research is similar to undercover police work.

Naturalistic Observation

Researchers use naturalistic observation when they are interested in how humans or other animals behave in their natural environments

For instance, two well-known observational studies were done by Dian Fossey in a study of mountain gorillas in Africa, and Jane Goodall’s study of chimpanzees in Africa

This technique is also used in settings such as schools, the workplace, and bars

Participant Observation

In most observational studies, the observer begins the study as a participant, whether in a laboratory or a natural setting

One famous example of participant observation was conducted by Rosenhan (1973). In this study, psychologists posing as patients with symptoms of a major mental disorder were admitted to psychiatric hospitals because the doctors could not tell the psychologists from the real disordered patients. Once admitted, these “pseudopatients” acted normally and asked to be released. However, they were not released until many days later!

Descriptive Methods:Case Studies

The researcher studies an individual in depth over an extended period of time to attempt to learn as much as possible about the individual being studied

Often used in clinical settings to gather information that will help in the treatment of the patient

Results of case studies cannot be generalized to other people

Descriptive Methods:Case Studies

Case studies do allow the researcher to develop hypotheses that can be tested using experimental research

For instance, the case of H. M., who had his hippocampus removed for medical reasons at a young age, was a case study. H. M. seemed to have normal memory for information learned before the surgery, but didn’t seem to be able to form any new memories. Such a finding led to the hypothesis that the hippocampus plays an important role in the formation of new memories, which was supported by subsequent experimental research.

Descriptive Methods:Survey Research

Uses questionnaires and interviews to collect information about the behavior, beliefs, and attitudes of particular groups of people

It is critical to note that the wording, order, and structure of the survey questions may lead the participants to biased answers For instance, some questions might evoke socially-

desirable responses in an effort to make certain impressions on the researchers

Descriptive Methods:Survey Research

Another concern for survey researchers is defining the population, or the entire group of people to be studied

From that population, a representative sample, or subset of the people in the population, is surveyed The sample must be representative of the larger

relevant population so you can generalize results of the survey from the smaller sample to the larger population

A representative sample?

In a study of women and love, a sample was drawn mainly from women’s organizations and political groups, plus some women who requested and completed a survey following the researcher’s talk show appearances

Thus, the results (which said that women having affairs and being disenchanted in their relationships with men was typical) were not representative of the population of American women

Random Sampling

Each individual in the population has an equal opportunity of being in the sample It is much like drawing

names from a hat Random sampling allows

the researcher to generalize his or her findings from the sample to the larger population

Correlational Methods

Two variables are measured to determine if they are related A variable is any factor that can take on more

than one value (e.g., height, age, GPA, extraversion level)

The Correlation Coefficient

A statistic that tells us the type and the strength of the relationship between two variables Range in value from -1.0

to +1.0 The sign of the

coefficient (- or +) tells us the type of relationship, positive or negative

Positive Correlation

A positive correlation indicates a direct relationship between two variables, with low scores on one variable tending to be paired with low scores on the other variable, and high scores on one variable tending to be paired with high scores on the other variable For instance, SAT scores and first-year college

GPA tend to be positively correlated A person’s height and weight also tend to be

positively correlated

Negative Correlation

A negative correlation is an inverse relationship between two variables, with low scores on one variable tending to be paired with high scores on the other variable For instance, there is a negative correlation

between how much time a student watches TV and his or her grades in school

Mountain elevation level and temperature are also negatively correlated

Strength of Relationship

The second part of the correlation coefficient is its absolute value, which ranges from 0 to 1 Zero and absolute values near zero indicate no

relationship As the absolute value increases toward 1.0, the

strength of the relationship increases It is critical to note that the sign of the

coefficient tells us nothing about the strength of the relationship

Scatterplots

A scatterplot is a visual depiction of correlational data On the X axis are scores on one variable; on the

Y axis are scores on the second variable Each data point in the scatterplot is a person’s

scores on each of the two variables

The Third-Variable Problem Strong correlations give us excellent

predictability, but they do not allow us to draw cause-and-effect conclusions about the relationships between the two variables The third-variable problem occurs when a third,

unmeasured variable is responsible for the relationship observed between the two measured variables For example, the length of time a man is married is

negatively correlated with the amount of hair on his head Does this mean that being married longer causes a

man’s hair to fall out?

Experimental Research

The key aspect of experimental research is that the researcher controls the experimental setting

It is this control that allows the researcher to make cause-and-effect statements about the experimental results

Experimental Control

First, the experimenter controls for the influence of possible third-variables by making sure that they are held constant across all of the experimental groups/conditions

Second, the experimenter controls for any possible influence due to the individual characteristics of the participants, such as intelligence, by using random assignment, which is randomly assigning the participants to groups in an experiment to equalize participant characteristics across the various groups in the experiment

Designing an Experiment

When a researcher designs an experiment, the researcher begins with a hypothesis about the cause-and-effect relationship between two variables

One of the variables is assumed to be the cause, and the other variable is the one to be affected

The independent variable is the hypothesized cause, and the experimenter manipulates it

The dependent variable is the variable that is hypothesized to be affect by the independent variable and thus is measured by the experimenter

Designing an Experiment

The simplest of experiments is one with two groups, in which participants are randomly assigned to one of the groups

One of the groups will be exposed to the independent variable, and the other group will not be

The group exposed to the independent variable is called the experimental group

The group not exposed to the independent variable is called the control group

For example… If the hypothesis is that aerobic exercise reduces anxiety,

then the independent variable to be manipulated is aerobic exercise, and the dependent variable will be anxiety level

The experimental group will participate in some aerobic exercise program, and the control group will not

The experiment must measure the anxiety levels for the groups at the beginning of the study before the independent variable is manipulated and then again after the manipulation

If the two groups are truly equivalent, the average anxiety level for each group at the start of the study should be the same

If aerobic exercise does reduce anxiety, then we should see this difference in the second measurement at the end of the experiment

The Placebo Group

In addition to the experimental and control groups, we need to add a placebo group to improve the experiment

A placebo group is a group of participants that believes they are receiving treatment but are not

They receive a placebo, a harmless pill that has no active ingredients

For example, this group would be told they are getting an anti-anxiety drug, but they would only get a placebo

The Placebo Group

The placebo effect is improvement due to the expectation of improving because of receiving treatment The reduction of anxiety in the experimental group

participants may, in fact, be partially or completely due to a placebo effect

To conclude that the reduction of anxiety in the experimental group was not due to a placebo effect, it would have to be significantly greater than that observed for the placebo group

Inferential Statistical Analyses

Indicate the probability that the results of a study are due to random variation (chance)

Of course, the researchers would want this probability to be low

In statistics, a “significant” finding is one that has a probability less than 0.05 (1/20) that it is due to chance

Thus, a significant finding is one that is not likely due to chance

The Double-Blind Procedure

A control measure in which neither the experimenter nor the participants know which participants actually got the treatment and or got the placebo Controls for experimenter expectations If the experimenter knew which condition the

participants were in, then s/he might unintentionally treat them differently and thereby impact their behavior

Summary of Research Methods

How to Understand Research Results

Descriptive Statistics

Frequency Distributions

Types of Statistics

DescriptiveStatistics

Used to describe the data of a research study in a concise

fashion

DescriptiveStatistics

Used to describe the data of a research study in a concise

fashion

InferentialStatistics

Indicate the probability that the results of the

study are due to random variation

InferentialStatistics

Indicate the probability that the results of the

study are due to random variation

Descriptive Statistics

Two types of descriptive statistics Measures of central tendency Measures of variability

A researcher will also often examine a frequency distribution, which depicts in a table or graph, the number of participants receiving each score for a variable

Measures of Central Tendency

Designed to summarize a set of data with a single number Three measures of central tendency

1. The mean is the numerical average for a distribution of score

2. The median is the score that is positioned in the middle of the distribution of scores when scores are listed from lowest to highest

If there is an odd number of scores, the median is the middle score

If there is an even number of scores, the median is the average of the two center scores

3. The mode is the most frequently-occurring score in a distribution of scores

If two scores occur with equal frequency, both can be the mode

About the Mean…

The mean is the most commonly used measure of central tendency because it is used to analyze data in many inferential statistical tests

However, the mean, because it uses all scores in its computation, can be distorted by extremely high or extremely low scores

Measures of Variability

Designed to provide an idea of how scattered a set of scores tends to be

Two measures of variability1. The range is the difference between the highest and

lowest scores in a distribution of scores Like the mean, the range can be greatly distorted by

extremely high or extremely low scores

2. The standard deviation is the average extent to which the scores vary from the mean of the distribution

A small standard deviation means that scores do not vary very much from the mean

A larger standard deviation means that scores tend to vary greatly from the mean

Summary of Descriptive Statistics

Frequency Distributions

Organizes the data in a score distribution so that we know the frequency of each score

Types of distributions

NormalDistributions

NormalDistributions

SkewedDistributions

SkewedDistributions

Normal Distributions

The mean, the median, and the mode are all equal because the normal distribution is symmetric about its center

The percentage of scores falling within a certain number of standard deviations of the mean is set About 68% of the scores fall within 1 standard deviation

of the mean About 95% fall within 2 standard deviations of the mean More than 99% fall within 3 standard deviations of the

mean It is these percentages that give the normal

distribution its bell shape

The Normal Distribution

Normal Distributions with Different Standard Deviations

Percentile Rank

The percentage of scores below a specific score in a distribution of scores For instance, the percentile rank of a score that is 1

standard deviation above the mean is roughly 84% Note that you can never have a percentile rank

of 100% because it is impossible to outscore yourself You can, however, have a percentile rank of 0% if

you have the lowest score in the distribution

Skewed Distributions

Are asymmetrical in shape A right-skewed (also called positively

skewed) distribution is a frequency distribution in which there are some unusually high scores, but most scores tend to be low

A left-skewed (also called negatively skewed)

distribution is a frequency distribution in which there are some unusually low score, but most scores tend to be high

Sample Skewed Distributions

Skewed Distributions

Because unusually high or low scores distort a mean, such distortion occurs for the means of skewed distributions The mean for a right-skewed distribution is distorted

toward the tail created by the few high scores and so is greater than the median

The mean for a left-skewed distribution is distorted toward the tail created by the few low scores and so is less than the median

Consequently, when you have a skewed distribution, you should use the median because atypical scores in the distribution do not distort the median