AP Psych 1.3: Studies and Experimentation

## Experiments

**Experimentation and Research**

We tend to believe, after learning an outcome, that we would have foreseen it - the “I knew it all along” phenomenon.

Overconfidence: we tend to think that we know more than we do.

Overconfidence will inhibit critical thinking or creativity.

Critical Thinking

Thinking that does not blindly accept arguments and conclusions

Examine assumptions, find hidden values, evaluate evidence

OVERCONFIDENCE WILL INHIBIT THIS

**Parts of Research**

Theory

An explanation using an integrated set of principles that organizes and predicts observations.

Hypothesis

A testable prediction, often implied by a theory.

Operational Definition

A statement of procedures (operations) used to define research variables.

Replication

It repeats an experiment in order to compare results and figure out that your actual experiment was the correct answer, as well as whether the basic finding generalizes to other participants and circumstances.

Experimentation

An investigator manipulates one or more variables to observe their effect (i.e. on a mental process or behavior - a dependent variable

Done by random assignment of participants the experiment controls by other relevant factors

For a study to be considered an experiment, it needs to include either random assignment or manipulation of one independent variable

**Independent Variable**

Whatever is being manipulated in an experiment, which hopefully brings about change.

If there is a drug in the experiment, it is almost always the independent variable.

**Dependent Variable**

Whatever is being measured in the experiment, dependent on the IV.

The dependent variable would be the effect of the drug.

**Confounding Variables**

Anything that can influence or compromise the results of the experiment are the confounding variables.

The object of the experiment is to prove that A causes B!

## Descriptive Studies

**Descriptive Studies**

Psychologists describe behavior using three different methods:

Case studies

Surveys

Naturalistic observation

**Case Study**

They study one or more individuals in depth in hope of gaining information and learning things that hold true about us all

**Survey**

A technique used for finding the behavior or attitude of people, which is self reported

Done by questioning a representative, random sample of people

A random sample is a sample that accurately represents a population since each member has an equal chance of being included in the sample.

**Naturalistic Observation**

Observing and recording behavior in settings that are natural to the subjects without trying to change anything about the circumstances

## Phenomena, Bias, and Other Effects

**Hawthorne Effect**

There is no control group

Selecting a group of subjects to experiment with affects the performance, regardless of what the experiment is

Knowing they are in an experiment will change their performance either way

**False Consensus Effect**

We have a tendency to overestimate how much others share our beliefs or thoughts

**Placebo Effect**

The belief that a person is on the real drug, and even though they aren’t truly on the drug, experience the effects that are from the active agent.

Can act as a confounding variable

Works using the belief of positive expectations

**Experimenter Bias**

A confounding variable that is not consciously controlled

A double-blind procedure can stop any experimenter bias

## Parts of a Study

**Population**

All the cases in a group from which samples are drawn from during a study or similar experiment

**Samples**

There are two types of examples

Stratified: a population is divided into categories from which a random sample is taken

Random: Everyone in a population has an equal likelihood of being selected for a study

**Experimentation**

There are two conditions to experimentation

Experimental condition: the condition that exposes participants to one version of the independent variable

Control condition: the condition that contracts with the experimental condition, and serves as a comparison to evaluate the experiment’s effects.

Random assignment

Assigning participants to experimental and control groups by chance

Minimizes pre-existing differences between the people assigned to different groups.

Placebo

An inert substance or condition that is put into an experiment that is administered in place of an active agent, with the intent to see if it triggers the effect that characterizes the active agent.

Blind and Double-Blind Procedures

Blind procedures mean that the participants are unaware of which group they are in - experimental or control

Double-blind procedures mean that nobody, neither the participants or research staff, know which participants are in which groups, which is commonly used in drug evaluation studies.

## Correlation Studies

**Correlational Study**

Examines relationships between two variables

Correlation does NOT prove causation

Has a correlation coefficient from -1.0 to +1.0

A statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other

Defines the strength of a correlation

Positive means one variable increases with the other

Negative means as one increases, the other decreases

Positive vs. negative correlation

Positive correlation means that the variables go in the same direction

Negative correlation means that the variables go in opposite directions

**Scatter Plot**

A graphed cluster of dots, each of which represents the values of two variables

The slope of the points suggests the direction of the relationship

The amount of scatter suggests the strength of the correlation

little scatter indicates high correlation

Also called a scattergram or scatter diagram

## Interpreting Data

**Measures of Central Tendency**

Ways to determine parts of data, including those of variables that occur most frequently, those that are in the middle of a dataset, and the average of the results.

Mean, median, and mode

**Approving an Experiment**

An experiment must be approved before it can be conducted

It has to be reviewed by the ethics board

The ethical guidelines are established by the American Psychology Association (APA).

**P-Value**

A hypothesis test that is used to determine the significance of the results from a study.

The probability that results from an experiment are due to chance and not the experimental conditions.

The null hypothesis is a prediction or claim about a population and hypothesis test

P-value is used to see how valid the null hypothesis claim is.

Range from 0 to 1

P value of less than .05 is statistically significant, as it had a less than .05% chance that it was chance and not the experimental conditions.

# AP Psych 1.3: Studies and Experimentation

## Experiments

**Experimentation and Research**

We tend to believe, after learning an outcome, that we would have foreseen it - the “I knew it all along” phenomenon.

Overconfidence: we tend to think that we know more than we do.

Overconfidence will inhibit critical thinking or creativity.

Critical Thinking

Thinking that does not blindly accept arguments and conclusions

Examine assumptions, find hidden values, evaluate evidence

OVERCONFIDENCE WILL INHIBIT THIS

**Parts of Research**

Theory

An explanation using an integrated set of principles that organizes and predicts observations.

Hypothesis

A testable prediction, often implied by a theory.

Operational Definition

A statement of procedures (operations) used to define research variables.

Replication

It repeats an experiment in order to compare results and figure out that your actual experiment was the correct answer, as well as whether the basic finding generalizes to other participants and circumstances.

Experimentation

An investigator manipulates one or more variables to observe their effect (i.e. on a mental process or behavior - a dependent variable

Done by random assignment of participants the experiment controls by other relevant factors

For a study to be considered an experiment, it needs to include either random assignment or manipulation of one independent variable

**Independent Variable**

Whatever is being manipulated in an experiment, which hopefully brings about change.

If there is a drug in the experiment, it is almost always the independent variable.

**Dependent Variable**

Whatever is being measured in the experiment, dependent on the IV.

The dependent variable would be the effect of the drug.

**Confounding Variables**

Anything that can influence or compromise the results of the experiment are the confounding variables.

The object of the experiment is to prove that A causes B!

## Descriptive Studies

**Descriptive Studies**

Psychologists describe behavior using three different methods:

Case studies

Surveys

Naturalistic observation

**Case Study**

They study one or more individuals in depth in hope of gaining information and learning things that hold true about us all

**Survey**

A technique used for finding the behavior or attitude of people, which is self reported

Done by questioning a representative, random sample of people

A random sample is a sample that accurately represents a population since each member has an equal chance of being included in the sample.

**Naturalistic Observation**

Observing and recording behavior in settings that are natural to the subjects without trying to change anything about the circumstances

## Phenomena, Bias, and Other Effects

**Hawthorne Effect**

There is no control group

Selecting a group of subjects to experiment with affects the performance, regardless of what the experiment is

Knowing they are in an experiment will change their performance either way

**False Consensus Effect**

We have a tendency to overestimate how much others share our beliefs or thoughts

**Placebo Effect**

The belief that a person is on the real drug, and even though they aren’t truly on the drug, experience the effects that are from the active agent.

Can act as a confounding variable

Works using the belief of positive expectations

**Experimenter Bias**

A confounding variable that is not consciously controlled

A double-blind procedure can stop any experimenter bias

## Parts of a Study

**Population**

All the cases in a group from which samples are drawn from during a study or similar experiment

**Samples**

There are two types of examples

Stratified: a population is divided into categories from which a random sample is taken

Random: Everyone in a population has an equal likelihood of being selected for a study

**Experimentation**

There are two conditions to experimentation

Experimental condition: the condition that exposes participants to one version of the independent variable

Control condition: the condition that contracts with the experimental condition, and serves as a comparison to evaluate the experiment’s effects.

Random assignment

Assigning participants to experimental and control groups by chance

Minimizes pre-existing differences between the people assigned to different groups.

Placebo

An inert substance or condition that is put into an experiment that is administered in place of an active agent, with the intent to see if it triggers the effect that characterizes the active agent.

Blind and Double-Blind Procedures

Blind procedures mean that the participants are unaware of which group they are in - experimental or control

Double-blind procedures mean that nobody, neither the participants or research staff, know which participants are in which groups, which is commonly used in drug evaluation studies.

## Correlation Studies

**Correlational Study**

Examines relationships between two variables

Correlation does NOT prove causation

Has a correlation coefficient from -1.0 to +1.0

A statistical measure of the extent to which two factors vary together, and thus how well either factor predicts the other

Defines the strength of a correlation

Positive means one variable increases with the other

Negative means as one increases, the other decreases

Positive vs. negative correlation

Positive correlation means that the variables go in the same direction

Negative correlation means that the variables go in opposite directions

**Scatter Plot**

A graphed cluster of dots, each of which represents the values of two variables

The slope of the points suggests the direction of the relationship

The amount of scatter suggests the strength of the correlation

little scatter indicates high correlation

Also called a scattergram or scatter diagram

## Interpreting Data

**Measures of Central Tendency**

Ways to determine parts of data, including those of variables that occur most frequently, those that are in the middle of a dataset, and the average of the results.

Mean, median, and mode

**Approving an Experiment**

An experiment must be approved before it can be conducted

It has to be reviewed by the ethics board

The ethical guidelines are established by the American Psychology Association (APA).

**P-Value**

A hypothesis test that is used to determine the significance of the results from a study.

The probability that results from an experiment are due to chance and not the experimental conditions.

The null hypothesis is a prediction or claim about a population and hypothesis test

P-value is used to see how valid the null hypothesis claim is.

Range from 0 to 1

P value of less than .05 is statistically significant, as it had a less than .05% chance that it was chance and not the experimental conditions.