Chapter 1
Outline
● The Goal of Scientific Psychology
● Sources of Knowledge
● What is a Theory?
● Induction and Deduction
● Evaluating Theories
● Psychology as a Science
The Goal of Scientific Psychology
● The goal of scientific psychology is to understand why people think and act the way they
do
● And we go about this using the scientific method
● An Example: Social Loafing
○ When individuals are working in groups, they tend to work less hard than they
would have if they were on their own
○ How can we go about studying this?
○ Ringelmann (1913)
■ Individuals pulled a rope
■ Would pull themselves by, with one other person, with two other people,
or with seven other people
■ Used sensitivity gauge to see the extent individuals pulled
■ Found that groups of two pulled at 95% of their combined capacity,
groups of three pulled at 85% capacity, and groups of eight pulled at 49%
of capacity
● What do the findings of Ringelmann (1913) suggest?
○ When in groups, individuals exert less effort than they would alone
○ But is it an experiment?
● Further Work
○ Latané and colleagues would go on to build on the work of Ringelmann (1913)
○ Brought individuals into the lab and showed same phenomenon could be obtained
in other situations and across cultures
○ Developed a theory known as diffusion of responsibility as a reason for social
loafing
■ When in groups, we feel less responsible for action
● This is what this class is all about…
○ We are going to work on understanding this process
How do experimental psychologists go from question, to hypothesis, to
, experimental development, data collection, analyses, and to interpretation
of results?
Sources of Knowledge
● Sources of Knowledge (Pierce, 1877)
○ Experimental psychologists use the scientific method to obtain knowledge and
form beliefs about the world
○ But where else do we get knowledge? What else do we use to form our beliefs?
■ Method of Authority
● We obtain knowledge from those who are considered an authority
○ We may believe what we see on the news because the news
is an authority
○ You may believe everything I say because I have been
trained in this field
● We lack time and resources to investigate everything we learn, we
take what is told to us by authorities as truth
■ Method of Tenacity
● We refuse to alter acquired knowledge, even in the face of contrary
evidence
○ I do not like mushrooms, regardless of how they are cooked
○ Forms of bigotry → to maintain their beliefs of other
people
○ This is a form of “fixed belief”. I refuse to alter what I
believe!
● We may use the method of tenacity to fix our beliefs to avoid the
stress or discomfort associated with having to change our beliefs
■ Method of a Priori
● “A Priori” = before experience/observation
● Method of a priori refers to something that is believed without
prior study or examination
● If it’s reasonable, it’s believable
● Examples
○ At one time, we believed the world was flat (IT”S NOT)
■ Scientific Method
● Knowledge, and the associated beliefs we form based on this
knowledge, is based on experience
○ In other words, the scientific method is empirical (it is
based on observation of experiences).
Outline
● The Goal of Scientific Psychology
● Sources of Knowledge
● What is a Theory?
● Induction and Deduction
● Evaluating Theories
● Psychology as a Science
The Goal of Scientific Psychology
● The goal of scientific psychology is to understand why people think and act the way they
do
● And we go about this using the scientific method
● An Example: Social Loafing
○ When individuals are working in groups, they tend to work less hard than they
would have if they were on their own
○ How can we go about studying this?
○ Ringelmann (1913)
■ Individuals pulled a rope
■ Would pull themselves by, with one other person, with two other people,
or with seven other people
■ Used sensitivity gauge to see the extent individuals pulled
■ Found that groups of two pulled at 95% of their combined capacity,
groups of three pulled at 85% capacity, and groups of eight pulled at 49%
of capacity
● What do the findings of Ringelmann (1913) suggest?
○ When in groups, individuals exert less effort than they would alone
○ But is it an experiment?
● Further Work
○ Latané and colleagues would go on to build on the work of Ringelmann (1913)
○ Brought individuals into the lab and showed same phenomenon could be obtained
in other situations and across cultures
○ Developed a theory known as diffusion of responsibility as a reason for social
loafing
■ When in groups, we feel less responsible for action
● This is what this class is all about…
○ We are going to work on understanding this process
How do experimental psychologists go from question, to hypothesis, to
, experimental development, data collection, analyses, and to interpretation
of results?
Sources of Knowledge
● Sources of Knowledge (Pierce, 1877)
○ Experimental psychologists use the scientific method to obtain knowledge and
form beliefs about the world
○ But where else do we get knowledge? What else do we use to form our beliefs?
■ Method of Authority
● We obtain knowledge from those who are considered an authority
○ We may believe what we see on the news because the news
is an authority
○ You may believe everything I say because I have been
trained in this field
● We lack time and resources to investigate everything we learn, we
take what is told to us by authorities as truth
■ Method of Tenacity
● We refuse to alter acquired knowledge, even in the face of contrary
evidence
○ I do not like mushrooms, regardless of how they are cooked
○ Forms of bigotry → to maintain their beliefs of other
people
○ This is a form of “fixed belief”. I refuse to alter what I
believe!
● We may use the method of tenacity to fix our beliefs to avoid the
stress or discomfort associated with having to change our beliefs
■ Method of a Priori
● “A Priori” = before experience/observation
● Method of a priori refers to something that is believed without
prior study or examination
● If it’s reasonable, it’s believable
● Examples
○ At one time, we believed the world was flat (IT”S NOT)
■ Scientific Method
● Knowledge, and the associated beliefs we form based on this
knowledge, is based on experience
○ In other words, the scientific method is empirical (it is
based on observation of experiences).
