Experimental research

Summary

In this educational video, Professor Doug Crawl from Northern Kentucky University explains the concept of experimental research in psychology. He illustrates how the study of variables can reveal causal relationships, using the example of whether violent media increases aggression. The video clarifies the roles of independent and dependent variables and addresses potential confounds in experimental design. It emphasizes the importance of random assignment to ensure that any observed effects can be attributed to the independent variable, thus establishing causality.

Takeaways

• 🧑‍🏫 Experimental research aims to determine if one variable causes another, which is crucial in psychology.
• 🔍 Examples of experimental research questions include whether certain therapies reduce depression or if specific techniques reduce violent crime.
• 🎬 A basic experimental study might involve showing participants either a violent film clip or a neutral one, like a documentary on penguins.
• 🔄 The independent variable is what the experimenter manipulates (e.g., type of film), while the dependent variable is what is measured (e.g., levels of aggression).
• ❓ The goal is to see if changes in the independent variable cause changes in the dependent variable.
• ⚠️ Confounds occur when there are multiple possible explanations for the findings, such as differences between participant groups.
• 🔀 Random assignment helps eliminate confounds by evenly distributing participant characteristics across experimental conditions.
• 📊 By ensuring groups are similar before the experiment, any differences found afterward can be attributed to the manipulation of the independent variable.
• ✅ Proper random assignment and control of variables allow researchers to determine causality in experimental research.
• 🎓 The example highlights the importance of controlling extraneous variables to make valid causal inferences in psychological studies.

Q & A

What is experimental research?

Experimental research seeks to discover if one variable causes another, often used in psychology to determine causal effects.

Can you provide an example of a question experimental research might seek to answer in psychology?

One example is determining whether a particular type of therapy reduces levels of depression.

What are independent and dependent variables in experimental research?

Independent variables are the ones that the experimenter controls or manipulates, while dependent variables are the ones being measured and are expected to change in response to the independent variable.

In the example of studying the effect of violent media on aggression, what are the independent and dependent variables?

The independent variable is the type of film watched (violent or neutral), and the dependent variable is the level of aggression observed in viewers.

What is a confound in experimental research?

A confound is a situation where there is more than one possible explanation for the findings, making it unclear what caused the observed effect.

How can confounds affect the validity of an experiment's results?

Confounds can lead to incorrect conclusions because they introduce alternative explanations for the observed effects, making it difficult to determine the true cause.

What strategy can be used to eliminate confounds in an experiment?

Random assignment can be used to mix up participants from different groups, ensuring that the groups are equal before the experiment begins and eliminating potential confounds.

Why is random assignment important in experimental research?

Random assignment ensures that participants are evenly distributed across experimental conditions, making the groups equal ahead of time and allowing for a clearer determination of causality.

What might an experimenter do to ensure the conditions are the same for all participants?

The experimenter can control variables such as the environment, instructions, and timing, ensuring everything is the same except for the independent variable being tested.

How does random assignment help in determining causality in an experiment?

By making the groups equal ahead of time, random assignment allows any differences observed after the manipulation of the independent variable to be attributed to that variable, thus helping to establish causality.

Outlines

00:00

🔬 Understanding Experimental Research

Doug Crawl, a professor of psychological science at Northern Kentucky University, introduces the concept of experimental research, which aims to establish causality between variables. He uses the example of determining whether violent media increases aggression in viewers. The explanation includes the distinction between independent variables (e.g., the type of film watched) and dependent variables (e.g., levels of aggression measured). Crawl outlines a hypothetical study design involving football players and band members watching either a violent or a neutral film clip to test the hypothesis.

Keywords

💡Experimental Research

Experimental research is a method of inquiry that aims to establish a cause-and-effect relationship between variables. In the context of the video, it is used to determine whether exposure to violent media increases aggression among viewers. The script uses the example of a study where participants are exposed to either a violent or a neutral film clip to illustrate how experimental research can be conducted.

💡Causal Effect

A causal effect is the impact one variable has on another, where a change in the first variable results in a change in the second. The video discusses the importance of identifying causal effects in psychology, such as whether a specific therapy reduces depression levels. The script's example of violent media and aggression demonstrates the search for a causal effect.

💡Independent Variable

The independent variable is the element that an experimenter manipulates in an experiment to observe its effect on another variable. In the script, the independent variable is the type of film clip—violent or neutral—that participants watch, with the expectation that it will influence their aggression levels.

💡Dependent Variable

The dependent variable is the outcome that is measured in an experiment, which is expected to change in response to the independent variable. In the video's example, the dependent variable is the level of aggression displayed by the participants after watching the film clips.

💡Confound

A confound in experimental research refers to an extraneous variable that could potentially explain the results, apart from the independent variable. In the script, the initial study's confound is the difference between football players and band members, which could affect aggression levels, not the film clips.

💡Random Assignment

Random assignment is a technique used in experiments to distribute participants into different groups to control for confounding variables. The script describes how random assignment can be used to ensure that both the violent and neutral film groups have a mix of football players and band members, thus reducing the chance of confounding effects.

💡Control Condition

A control condition in an experiment serves as a baseline for comparison against the experimental condition. In the video, the control condition involves participants watching a neutral film clip about penguins, which is used to compare against the aggression levels of those who watched the violent film clip.

💡Experimental Condition

The experimental condition is the scenario in which the independent variable is manipulated. In the script, the experimental condition is where participants watch a violent film clip, which is intended to increase their aggression levels for comparison with the control group.

💡Aggression

Aggression, in the context of the video, is the dependent variable being measured to determine the effect of watching violent media. The script discusses how aggression levels are expected to be higher in the group exposed to violent film clips compared to the control group.

💡Pretreatment

Pretreatment refers to measurements taken before the experiment begins to assess the initial state of the participants. Although not explicitly mentioned in the script, the concept is implied when discussing the possibility of checking if the groups are equal in aggression levels before the experiment starts.

💡Causality

Causality is the relationship between a cause and its effect. The video emphasizes that through proper experimental design, including random assignment and control of confounding variables, researchers can establish causality, such as determining that violent films cause increased aggression.

Highlights

Doug Crawl introduces himself as a professor in the department of psychological science at Northern Kentucky University.

The lecture focuses on experimental research and its aim to discover causal relationships between variables in psychology.

Examples provided include the effect of therapy on depression levels and the impact of memory strategies on recall.

The concept of experimental conditions is introduced, with a study on whether violent media increases aggression in viewers.

The importance of distinguishing between experimental and control conditions in a study is emphasized.

Terminology of independent and dependent variables is explained, with the experimenter controlling the former.

An example study design is proposed, involving football players and band members watching different film clips.

The potential problem of confounding variables is discussed, where other factors could explain the findings.

The solution to confounding is presented through the method of random assignment to ensure equal groups.

Random assignment is highlighted as a means to eliminate confounding factors and establish causality.

The practical application of the study is demonstrated through a hypothetical scenario involving film clips and participants.

The significance of pretests to check for group equality before the experiment is mentioned.

The necessity of maintaining consistent conditions during the experiment, except for the independent variable, is stressed.

The conclusion that experiments allow for the determination of causality is drawn from the study design and findings.

The transcript concludes with the assertion that experimental research is crucial for establishing causal relationships in psychology.

The lecture provides a clear methodology for conducting experimental research and understanding its implications.

Transcripts

my name is Doug crawl I'm a professor in

the department of psychological science

at Northern Kentucky University and I'm

going to talk to you about experimental

research experimental research seeks to

discover if one variable causes another

and this is something that we often want

to know in psychology so for example we

we might want to know does a particular

type of therapy really reduce levels of

depression or does a particular memory

strategy really help people to remember

or maybe does a particular technique

that we can use in communities really

reduce violent crime or increase helping

behavior or something along those lines

and so we often want to know if one

variable does have a causal effect on

another one let me give you an example

of how this might be done let's suppose

that I want to know if violent media

increases aggression in viewers which

research suggests that it does in

general and let's suppose I do a pretty

simple study with just two conditions in

one condition the experimental condition

people watch a violent film clip and

then in the other condition the control

condition they watch some neutral film

clip maybe a documentary on Penguin's

something like that now let me give you

some terminology on this there's two

types of variables that we care about

with regard to experimentation

independent variables and dependent

variables the independent variables are

the ones that the experimenter messes

with in other words the experimenter

controls who's going to get what in this

case we have one independent variable

the film the experimenter decides some

people are going to see a violent film

clip other people are going to see a

neutral film clip the documentary on

Penguin's the dependent variable is the

one we measure in this case it would be

levels of aggression and the prediction

is that the independent variable is

going to influence the dependent

variable or that the dependent variable

will depend upon the independent

variable now let's suppose that I

actually wanted to do a study like that

it so happens there's a school not very

far from where I live so I could load

some film clips on some laptops and

perhaps get some people to help me and

go down there before a football game is

scheduled to begin

and perhaps people are standing around

waiting for the game to begin they have

time on their hands and so I think let's

see here I need some people from my

violent film condition football players

hey you big football players would you

mind coming over here I've got this film

clip it'll just take a couple of minutes

would you mind watching them then I'll

ask you some questions would that be

okay terrific and so I do that and I

think I need some people for my

nonviolent film condition the band band

members would you mind coming over here

and watching this film clip just take a

couple of minutes and then I'll ask you

some questions would that be alright

terrific

it's a let's I let's suppose I do that

and I discover that people in the

violent film condition indeed turn out

to be more aggressive than people in the

nonviolent film condition and so I

conclude that violent films do in fact

increase aggression except as you

probably noticed I have a problem don't

I I have a problem that we refer to as a

confound a confound is where I have more

than one possible explanation for my

finding it could be the film really is

responsible maybe that really is the

reason why aggression levels were higher

but it might not be that it could be

because of differences between the

football players and the band members in

the film has nothing to do with it and

so notice that a confound isn't that I

failed to find something I did find

something I just don't know why I found

what I found

all right let's suppose that I want to

fix this problem and let's suppose that

I only have football players and band

members as possible participants what

could I do as some of you might have

realized I need to mix them up I need to

do something so that I end up with some

football players and some band members

over here in the violent film group and

some football players and some band

members over here in the penguin group

and let's suppose I do that and so we we

flip a coin or something like that if it

comes up heads we put them in the

violent film group it comes up tails we

put them in the penguin group and that

let's suppose that I still find that

people show higher aggression levels in

the violent film group compared to the

control condition then I can conclude

that the violent film really is

responsible you might be able to see why

it's like random assignment is supposed

to make the group's equal ahead of time

you can even check do some sort of

pretest if you really want to see if the

groups are equal in this case in

aggression

levels but random assignment works so

well we usually don't even bother to

check that and so if the groups are

equal ahead of time and then I do

everything the same the experimenter is

the same we say the same things to

everyone the temperature in the room is

the same everything is the same except

the film clip and so now if we find a

difference they were the same at the

beginning everything was the same except

the film and now we find that they

differ in aggression levels clearly the

film must be responsible and so this is

why we say that experiments allow us to

determine causality