Psychology Chapter 2: Scientific Method & Intuition

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Questions and Answers

What is a primary problem with relying on intuition for conclusions?

Intuition often leads to more accurate conclusions.

Intuition is always based on extensive data collection.

Intuition discounts cases that don't match our beliefs. (correct)

Intuition allows for better scientific reasoning.

What is the theory-data cycle primarily concerned with?

Observations that are not quantifiable.

Developing theories based solely on intuition.

Testing theories by comparing them with collected data. (correct)

Collecting data to confirm or refute personal beliefs.

What is a hypothesis?

A collection of data from numerous studies.

An untested belief about human behavior.

A definitive conclusion drawn from extensive research.

A prediction of what will happen based on a theory. (correct)

What does replication in research ensure?

Results can be confirmed through repeated studies. Signup and view all the answers

Which of the following is not a characteristic of measured variables?

They are controlled by the researcher. Signup and view all the answers

What role do journals play in the scientific community?

They facilitate the peer review and publication of research. Signup and view all the answers

How is a manipulated variable defined?

A variable that the researcher assigns different levels to. Signup and view all the answers

What is the purpose of peer review in scientific publishing?

To provide feedback and identify flaws in the manuscript. Signup and view all the answers

What does the null hypothesis assume?

There is no relationship between variables Signup and view all the answers

What is indicated when researchers find a p-value less than 0.05?

There may be a statistically significant effect Signup and view all the answers

Which scenario would lead researchers to reject the null hypothesis?

Sample results occur less than 5 percent of the time if null hypothesis is true Signup and view all the answers

What does effect size indicate?

The strength of the relationship between variables Signup and view all the answers

What is the main purpose of a meta-analysis in research?

To estimate the effect size of a body of studies Signup and view all the answers

Which ethical principle involves finding alternatives to animal testing?

Replacement Signup and view all the answers

What does the principle of refinement in animal research aim to achieve?

To minimize animal distress during experiments Signup and view all the answers

Why might a small sample size affect the validity of a study's findings?

It can lead to less statistical significance Signup and view all the answers

What does construct validity assess in a study?

How well a variable has been manipulated Signup and view all the answers

What is the primary focus of external validity in research?

Generalizing study results to a broader population Signup and view all the answers

Which measure describes the most common value in a data set?

Mode Signup and view all the answers

What is the main concern of internal validity in research?

Ruling out alternative explanations for the results Signup and view all the answers

What does standard deviation measure in a data set?

The degree of variation around the mean Signup and view all the answers

Which statistical method estimates whether results from a sample reflect the broader population?

Inferential statistics Signup and view all the answers

What does reliability refer to in the context of research measures?

The consistency of results across multiple administrations Signup and view all the answers

What aspect of a research study does the correlation coefficient (r) measure?

The strength of a correlation between variables Signup and view all the answers

What does a frequency distribution typically represent in research data?

A visual representation of scores from lowest to highest Signup and view all the answers

Which of the following is a concern when experiments have confounding variables?

It introduces alternative explanations for findings Signup and view all the answers

What does operationalizing a measured variable involve?

Turning a variable into a number Signup and view all the answers

What is the purpose of descriptive research in psychology?

To describe typical behaviors or characteristics of a sample Signup and view all the answers

How is a sample defined in research?

The specific individuals chosen to participate in a study Signup and view all the answers

What does a positive correlation indicate between two variables?

As one variable increases, the other variable also increases Signup and view all the answers

What is a limitation of correlational studies?

They cannot imply that one variable causes another Signup and view all the answers

Which method involves observing behavior in its natural environment without interference?

Naturalistic observation Signup and view all the answers

What kind of sampling ensures that a sample can generalize to the larger population?

Random sampling Signup and view all the answers

In a scatterplot, what does the x-axis typically represent?

The independent variable Signup and view all the answers

What should researchers rely on to operationalize variables that are not easily observable?

Technological tools Signup and view all the answers

What is a case study primarily focused on?

An individual or very small group Signup and view all the answers

What must be established to say that one variable causes another?

The two variables must be positively correlated. Signup and view all the answers

What is the primary purpose of random assignment in experimental research?

To assume similarity among groups at the start of the study. Signup and view all the answers

What is a control group in an experiment?

The group that is not exposed to the treatment. Signup and view all the answers

Which statement best describes the third variable problem?

A correlation between two variables may be explained by a third variable. Signup and view all the answers

In the context of experimentation, what is an independent variable?

The variable that is manipulated by the researcher. Signup and view all the answers

What is the purpose of the placebo condition in an experiment?

To distinguish physiological effects from participants' expectations. Signup and view all the answers

Which research method is typically utilized first to discover what is typical before establishing relationships between variables?

Descriptive study Signup and view all the answers

What does random sampling achieve in research?

It gives every person in the population an equal chance to be selected. Signup and view all the answers

Which variable is assessed for its effect in an experimental setup?

Dependent variable Signup and view all the answers

In the context of causal relationships, what does it mean for variables to be correlated?

Changes in one variable predict changes in another. Signup and view all the answers

What is a key issue with relying solely on intuition for forming conclusions?

It often leads to overconfidence and biased interpretations. Signup and view all the answers

During the theory-data cycle, what happens if the data contradicts the initial theory?

The theory must be re-evaluated or revised based on the new evidence. Signup and view all the answers

What distinguishes a manipulated variable from a measured variable?

Manipulated variables are controlled by the experimenter, while measured variables are observed. Signup and view all the answers

What is a significant aspect of replication in research studies?

It requires a different sample of participants to validate findings. Signup and view all the answers

What is the primary purpose of peer review in scientific research publications?

To identify strengths and weaknesses of a manuscript based on expert evaluation. Signup and view all the answers

In the context of hypotheses, what does a properly formulated hypothesis serve as?

A prediction that is based on established theories. Signup and view all the answers

How do measured variables typically differ from manipulated variables in research?

Measured variables are often represented in a numerical format. Signup and view all the answers

What is the significance of quantitative data in scientific research?

It provides the means to confirm or refute theories with concrete evidence. Signup and view all the answers

What is the main purpose of operationalizing measured variables?

To convert variables into quantifiable numbers for analysis Signup and view all the answers

Which of the following best describes a limitation of survey research?

It relies heavily on participants' self-reporting, which may be inaccurate Signup and view all the answers

In a scatterplot, what does a positive correlation indicate?

As one variable increases, the other variable also increases Signup and view all the answers

What is a key characteristic of naturalistic observation as a research method?

It seeks to minimize interference while observing behavior Signup and view all the answers

What is the implication of the statement 'correlations reveal relationships but are not enough to support causal claims'?

Correlation alone does not imply one variable directly affects another. Signup and view all the answers

Which method would researchers use to gather data about behavior when self-reporting may not be reliable?

Use naturalistic observation Signup and view all the answers

What role does random sampling play in research studies?

It guarantees that a sample represents the entire population of interest Signup and view all the answers

What is the primary goal of case studies in research?

To provide in-depth analysis of one individual or small group Signup and view all the answers

How is operationalizing a measured variable practically oriented?

It is made based on the feasibility and technological advancements available Signup and view all the answers

What does construct validity primarily assess in a study?

How well operationalizations capture the variables of interest Signup and view all the answers

Which concept focuses on whether the results of a study can generalize to a broader population?

External validity Signup and view all the answers

What aspect is crucial for ensuring strong internal validity in an experimental study?

Control of confounding variables Signup and view all the answers

Which measure indicates the average deviation from the mean in a dataset?

Standard deviation Signup and view all the answers

Which statistical approach allows researchers to infer population characteristics based on sample data?

Inferential statistics Signup and view all the answers

What does statistical significance testing help to determine?

Whether results are likely due to chance Signup and view all the answers

When assessing central tendency, which measure would represent the most frequently occurring response?

Mode Signup and view all the answers

What is the primary purpose of using random sampling in research?

To make the sample representative of the population Signup and view all the answers

Which type of validity focuses on the extent to which a study can rule out alternative explanations?

Internal validity Signup and view all the answers

What is the effect size used to describe in research?

The strength of a correlation or difference between groups Signup and view all the answers

What does a null hypothesis significance testing approach assume?

No significant effect is present in the data. Signup and view all the answers

Under what condition would researchers typically reject the null hypothesis?

When results would occur less than 5% of the time if the null hypothesis is true. Signup and view all the answers

What is the primary outcome when researchers identify a large effect size?

It implies a higher likelihood of statistical significance. Signup and view all the answers

What does the term 'meta-analysis' refer to in research methodology?

Combining results from multiple studies to estimate overall effect size. Signup and view all the answers

Which of the following represents the ethical principle of 'reduction' in animal research?

Using fewer animals in experiments without compromising data integrity. Signup and view all the answers

In hypothesis testing, what does it mean when p < 0.05?

The results are statistically significant, suggesting a real effect. Signup and view all the answers

What role does sampling play in the validity of research findings?

Random sampling helps ensure representativeness of the population. Signup and view all the answers

What does it imply if a sample is described as a 'good estimate' of the population?

It accurately reflects the true characteristics of the population. Signup and view all the answers

What is the main purpose of random assignment in experimental research?

To guarantee that the experimental and control groups are similar at the start Signup and view all the answers

Which of the following correctly describes the independent variable in an experiment?

The variable being manipulated by the researcher Signup and view all the answers

What constitutes an essential requirement for establishing a causal relationship between two variables?

The independent variable must precede the dependent variable in time Signup and view all the answers

What is the consequence of a third variable problem in correlational studies?

It creates the possibility of misattributing causality Signup and view all the answers

Why might researchers include a placebo condition in an experiment?

To isolate the effects of a treatment from participants' expectations Signup and view all the answers

What defines the role of the experimental group in a scientific study?

This group is used to manipulate an independent variable Signup and view all the answers

What best describes the distinction between random sampling and random assignment?

Random sampling ensures each individual has an equal chance of being selected for the study Signup and view all the answers

In the context of correlation and causation, what is a critical factor that must be met regarding variable relationships?

Alternative explanations for the correlation must be ruled out Signup and view all the answers

How does experimental research manipulate causal variables?

By assigning different levels of treatment to participants Signup and view all the answers

What can significantly alter our conclusions when relying on intuition?

Effect of confirmation bias Signup and view all the answers

What is the role of replication in the scientific method?

To confirm results across different samples Signup and view all the answers

How is a measured variable distinct from a manipulated variable?

Measured variables display naturally occurring differences. Signup and view all the answers

What is the primary purpose of peer review in scientific journals?

To ensure validity and credibility of research Signup and view all the answers

Which of the following best defines a hypothesis within the scientific method?

A testable prediction based on theory Signup and view all the answers

What can be a consequence of overconfidence in one's intuition during research?

Neglect of contradictory evidence Signup and view all the answers

What characterizes the theory-data cycle in research?

Theories evolve based on observed data. Signup and view all the answers

How are variables categorized within research frameworks?

In terms of their ability to vary and their measurement approach Signup and view all the answers

What must be established to convincingly assert that one variable causes another?

The timing of events and lack of alternative explanations must be known. Signup and view all the answers

In experimental research, what is the purpose of random assignment?

To minimize any potential biases between experimental conditions. Signup and view all the answers

Which of the following accurately describes a control group in an experiment?

The group that lacks exposure to the independent variable. Signup and view all the answers

What is a potential issue with the third variable problem in correlational research?

It suggests that a third variable may influence the observed correlation. Signup and view all the answers

What distinguishes an independent variable from a dependent variable in an experiment?

The independent variable is hypothesized cause, while the dependent variable is the measured effect. Signup and view all the answers

Which condition is essential for researchers to effectively separate physiological effects from expectations in an experimental setup?

Including a placebo condition in the experimental design. Signup and view all the answers

What is the outcome of an effective experimental design when a participant believes they are being manipulated?

It maintains the integrity of physiological measurements. Signup and view all the answers

Which scenario illustrates the importance of demonstrating that one variable precedes another in establishing causation?

Wealth influencing generosity must account for timing of wealth acquisition. Signup and view all the answers

When researchers employ both random sampling and random assignment, what is the primary benefit?

They assure unbiased representation in the study sample and treatment groups. Signup and view all the answers

What is the primary assumption of the null hypothesis in research studies?

There is no relationship between the variables. Signup and view all the answers

What does it indicate when researchers encounter a p-value less than 0.05?

The result is statistically significant. Signup and view all the answers

Which statement best describes the concept of effect size in research?

It indicates the strength of the relationship between variables. Signup and view all the answers

In the context of ethical research with animals, what does the principle of reduction emphasize?

Designing experiments to use the fewest number of animal subjects possible. Signup and view all the answers

What does a researcher reject when they find that a sample's result would happen less than 5 percent of the time if the null hypothesis is true?

The null hypothesis. Signup and view all the answers

What is the role of meta-analysis in research?

To average the effect sizes of multiple studies. Signup and view all the answers

Which principle in ethical research involves modifying procedures to minimize distress in animals?

Refinement Signup and view all the answers

Why might a small sample size be a limitation in estimating population parameters?

It reduces the chance of detecting a significant effect. Signup and view all the answers

What is the primary goal of descriptive research?

To describe what is typical in behavior or responses Signup and view all the answers

Which of the following methods is used to operationalize variables that are not easily observable?

Technological measurement such as brain activation Signup and view all the answers

What characteristic differentiates a case study from naturalistic observation?

A case study focuses on one individual or a small group, while naturalistic observation examines behavior in everyday contexts Signup and view all the answers

What is indicated by a zero correlation between two measured variables?

No systematic relationship exists between the variables Signup and view all the answers

Which aspect of a research sample enhances the ability to generalize findings to a full population?

Random sampling techniques Signup and view all the answers

In correlational research, what does the scatterplot represent?

The relationship between two measured variables Signup and view all the answers

What does operationalizing a measured variable typically involve?

Turning an abstract variable into quantifiable numbers Signup and view all the answers

What type of correlation is suggested when one variable increases while another decreases?

Negative correlation Signup and view all the answers

How does descriptive research based on self-report differ from observational methods?

Descriptive research relies on participants' perceptions while observational methods measure actual behavior Signup and view all the answers

Which statement accurately describes a limitation of correlational studies?

They fail to provide insights into the directionality of relationships Signup and view all the answers

Which of the following best describes internal validity in research?

The extent to which the study can rule out alternative explanations. Signup and view all the answers

What is external validity primarily concerned with?

The extent to which results can be generalized to broader populations. Signup and view all the answers

How is reliability defined in the context of research measures?

The consistency of a measure across multiple administrations. Signup and view all the answers

Which of the following best describes a frequency distribution?

A visual representation of individual scores across a variable. Signup and view all the answers

What does the term 'operationalization' refer to in research?

The manipulation of a variable to measure its effects. Signup and view all the answers

Which statistical concept describes the strength of a relationship between two variables?

Effect size. Signup and view all the answers

What does statistical significance testing aim to determine?

If results are due to random chance. Signup and view all the answers

Which measure would be best to assess how much scores vary from the average in a dataset?

Standard deviation. Signup and view all the answers

What does the mean refer to in statistical terms?

The average of a set of scores. Signup and view all the answers

Which of the following would be a concern regarding confounding variables in research?

They can introduce alternative explanations for the results. Signup and view all the answers

What is a potential consequence of overconfidence in our intuitive judgments?

We tend to ignore contradictory evidence. Signup and view all the answers

Which best describes a measured variable?

A variable that can be quantified and observed. Signup and view all the answers

What is the role of peer review in scientific publications?

To evaluate a manuscript's scientific merit by other experts. Signup and view all the answers

What aspect of a hypothesis makes it critical in research?

It provides a clear prediction about expected outcomes. Signup and view all the answers

In the context of the theory-data cycle, what happens if data do not align with the existing theory?

The theory may need to be revised or rejected. Signup and view all the answers

What is a fundamental characteristic of manipulated variables in research studies?

They are controlled and varied by the researcher. Signup and view all the answers

Why is replication important in scientific research?

It verifies that results can be consistently reproduced. Signup and view all the answers

What distinguishes a theory from a hypothesis in research?

A theory comprises broader explanations than a hypothesis. Signup and view all the answers

What aspect of construct validity is assessed regarding the manipulative variable in a study?

How well the variable has been manipulated Signup and view all the answers

Which of the following describes the importance of external validity in research?

It evaluates if the findings can be applied to different populations. Signup and view all the answers

What is the primary focus of internal validity in a research study?

Assessing whether alternative explanations can be ruled out Signup and view all the answers

Which measure describes the degree to which scores in a data set vary from the mean?

Standard deviation Signup and view all the answers

What is critical for determining statistical significance in research findings?

The likelihood that the results occurred by chance. Signup and view all the answers

In terms of data representation, what does a frequency distribution visually communicate?

The total number of occurrences for scores of a variable Signup and view all the answers

What does the term 'effect size' refer to in research?

The magnitude of the association or difference found in the research Signup and view all the answers

What does reliability specifically assess in research measures?

The extent to which a measure produces consistent results Signup and view all the answers

How are inferential statistics used in research?

To infer truths about a larger population based on sample data Signup and view all the answers

Which of the following describes the role of random sampling in research?

To ensure that the sample is representative of the population Signup and view all the answers

What does the null hypothesis specifically assume about the relationship between variables?

There is no relationship between the variables. Signup and view all the answers

In null hypothesis significance testing, what is indicated if a sample’s result occurs less than 5 percent of the time under the null hypothesis?

The result is statistically significant. Signup and view all the answers

Which of the following best defines effect size in research?

The strength or magnitude of a relationship or difference. Signup and view all the answers

What is the purpose of conducting a meta-analysis in research?

To average the results of multiple studies to estimate overall effect size. Signup and view all the answers

Which ethical principle emphasizes reducing the number of animal subjects used in research?

Reduction Signup and view all the answers

What does a p-value less than 0.05 imply in the context of research findings?

The sample results contradict the null hypothesis. Signup and view all the answers

Which approach is suggested to ensure ethical standards in research involving animals?

Implement procedures to minimize distress and consider alternatives. Signup and view all the answers

What is the primary consideration when rejecting the null hypothesis based on sample results?

The results should occur with a low probability if the null hypothesis is true. Signup and view all the answers

Which of the following is NOT a criterion necessary to establish a causal relationship between two variables?

The independent variable must be experimentally manipulated. Signup and view all the answers

In an experiment, what is the primary role of the control group?

To establish a baseline for comparison against the experimental group. Signup and view all the answers

What type of assignment ensures that participants have an equal chance of being placed in any experimental condition?

Random assignment. Signup and view all the answers

Which term describes the phenomenon when a correlation between two variables is influenced by a third variable?

Third variable problem. Signup and view all the answers

What is the effect of using a placebo condition in an experiment?

It isolates psychological effects from physiological responses. Signup and view all the answers

Which research method is primarily used to establish relationships between variables after conducting a descriptive study?

Correlational study. Signup and view all the answers

Which of the following terms refers to the variable that is manipulated in an experiment?

Independent variable. Signup and view all the answers

What does random sampling aim to achieve in research?

Selecting participants without bias. Signup and view all the answers

Which aspect of research does internal validity primarily concern?

Establishment of a causal relationship. Signup and view all the answers

What is the primary purpose of conducting controlled experiments?

To establish causal relationships. Signup and view all the answers

What is the main goal of descriptive research that relies on self-report?

To describe typical behaviors or characteristics Signup and view all the answers

In correlational studies, which of the following statements about scatterplots is true?

A positive correlation indicates that both variables increase together Signup and view all the answers

What type of sampling allows researchers to generalize their findings to a larger population?

Random sampling Signup and view all the answers

Which of the following best describes naturalistic observation in research?

Observing subjects in their everyday environments without interference Signup and view all the answers

How is a case study different from other observational methods?

It typically involves studying a single individual or a small group Signup and view all the answers

Which aspect of correlational studies limits the ability to assert causation?

The potential influence of external variables unaccounted for Signup and view all the answers

What is an example of operationalizing a measured variable through technology?

Using blood samples to measure intoxication levels Signup and view all the answers

What does a zero correlation indicate about two measured variables?

They are independent and generally unrelated Signup and view all the answers

What principle guides the choice of how to operationalize a measured variable?

Practical reasons and feasibility of measurement Signup and view all the answers

What is a significant limitation of surveys used in descriptive research?

They may not accurately reflect individual behaviors Signup and view all the answers

Study Notes

Limits of Intuition and Experience

Our intuition can be unreliable because we tend to be overconfident in our knowledge and understanding.
We tend to discount contradictory information that doesn't align with our preconceived notions.

The Scientific Method: Testing Theories with Data

The scientific method involves a cycle of developing theories about human behavior and using data to test those theories.
Data either confirms or disproves the theory.
A hypothesis is a prediction based on a theory.
Data is collected from participants in the form of observations and numerical values.
Replication means repeating a study on a new sample of participants to verify the original findings.
Scientific research is shared through peer-reviewed journals, where experts assess the manuscript's strengths and weaknesses.

Variables: The Building Blocks of Research

A variable is any characteristic that can vary from person to person or situation.
Measured variables are observed and recorded in numerical form (e.g., height, braking time).
Manipulated variables are controlled by researchers by assigning participants to different levels of the variable (e.g., level of intoxication).
Manipulated variables are only used in experiments.

Operationalizing Measured Variables

Operationalization means turning a variable into a number.
Self-report methods ask participants to describe themselves using a scale (e.g., 0 to 1).
Direct observation involves counting or recording the duration of specific behaviors.
Technology can be used to operationalize variables that are not easily observable (e.g., blood alcohol level, brain activation).

Surveys : Descriptive Research Based on Self-Report

Descriptive research focuses on understanding the typical characteristics of a variable.
Survey research provides concise summaries of large groups of people.
Random sampling ensures that the sample accurately represents the population of interest.

Descriptive Research Based on Naturalistic Observations and Case Studies

Naturalistic observation involves observing the behavior of animals or people in their natural environments without interference.
Case studies are naturalistic observations conducted on a single individual or a small group, often used to study rare phenomena.

Correlational research involves measuring two or more variables to understand their relationship.
Data from correlational studies is often presented in scatterplots, where each dot represents one participant.
Positive correlation: as one variable increases, the other variable also increases.
Negative correlation: as one variable increases, the other variable decreases.
Zero correlation: no systematic relationship between the two variables.

Correlations Reveal Relationships but Are Not Enough to Support Causal Claims

Correlation does not equal causation.
To establish a causal relationship between two variables, three criteria must be met:
- The variables must be correlated
- The cause must come before the effect in time.
- No other plausible explanations must exist.
The third variable problem refers to when a correlation between two variables is explained by the influence of a third, unmeasured, variable.

Experimental Research: Manipulating a Causal Variable to Observe Its Effect

Experimental research manipulates a variable hypothesized to be causal and observes the effects on a measured variable.
Independent variable: the hypothesized cause.
Dependent variable: the measured variable, the hypothesized effect.
Random assignment ensures that groups in an experiment are similar on average at the beginning of the study.
Experimental group: the group that receives the active ingredient or treatment.
Control group: the group that does not receive the active ingredient or treatment.
Placebo condition helps researchers distinguish between physiological effects and participants' expectations.

Random Assignment vs Random Sampling

Random means selecting or assigning something without bias.
Random sampling is a method for selecting participants for the study, where all members of the population have an equal chance of being selected.
Random assignment is a method for assigning participants to different levels of the independent variable.

Comparing and Contrasting Different Methods

Researchers may start with a descriptive study to understand typical characteristics, followed by a correlational study to establish relationships, and then a controlled experiment to establish causality.

Assessing Construct Validity: How Well Were the Variables Operationalized?

Construct validity refers to how well a variable has been operationalized.
It assesses how accurately the measures used in the study capture the variables of interest.
Reliability refers to the consistency of a measure over time.

Assessing External Validity: Are the People Studied Representative of a Broader Population?

External validity refers to the generalizability of the study's findings to the population of interest.
Random sampling increases external validity.

Assessing Internal Validity: Can We Rule Out Most Plausible Alternative Explanations?

Internal validity refers to the ability to rule out alternative explanations for the findings.
Experiments are more likely to have higher internal validity than correlational studies.
A confound occurs when experimental groups accidentally differ on more than just the independent variable.

Using Data to Describe People: Central Tendency and Standard Deviation

Descriptive statistics summarize participants' responses using measures of central tendency and variability.
Mean: the average of the scores.
Median: the middle value of the scores.
Mode: the most frequent value of the scores.
Standard deviation: a measure of how much scores vary from the mean.

Statistical Significance

Inferential statistics use samples to infer what is true about a larger population.
Statistical significance testing uses statistical rules to estimate whether the results obtained in a sample came from a specific population.
The null hypothesis assumes that there is no relationship between variables.
Null hypothesis significance testing assumes no significant effect.
If the likelihood of the sample results occurring under the null hypothesis is very low (typically less than 5%), the null hypothesis is rejected, and the findings are considered statistically significant.
A larger effect size increases the likelihood of statistical significance.
Meta-analysis averages the results of multiple studies to estimate the overall effect size.

Replication and High-Quality Science

Replication is essential for validating scientific findings and building confidence in those findings.
Failed replications can reveal limitations of the original study.
Open science practices increase transparency and collaboration in research, promoting replication.

Ethical Principles for Research with Humans

Informed consent ensures that participants understand the risks and benefits of participating in research.
Privacy and confidentiality protect participants' personal information.
Deception must be justified and minimized, and participants must be debriefed afterward.
Participants have the right to withdraw from a study at any time.
Research must be conducted ethically and contribute to the advancement of scientific knowledge.

Ethical Principles for Research with Animals

Replacement: using alternatives to animals when possible.
Refinement: minimizing animal distress.
Reduction: using the fewest animal subjects possible.
Ethical guidelines for research with animals emphasize minimizing harm and promoting animal welfare.

Limits of Intuition and Experience

Our intuition can sometimes lead us to wrong conclusions because we tend to overestimate what we know and how well we understand events.
Our biased intuitions tend to discount cases that do not match our expectations.

The Scientific Method: Testing Theories with Data

The theory-data cycle involves developing a theory about people’s behavior and collecting data to compare with the theory.
Data either supports or refutes the theory.
A hypothesis is a prediction about what will happen, based on the theory.
Data refers to observations from a study, usually in numerical form, and is collected from people under specific circumstances.
Replication means a study has been conducted more than once with different participants, achieving similar results.
Scientific research is shared in specialized scientific publications called journals.
Peer review is part of the publication process in which other experts in the field identify the strengths and weaknesses of a manuscript.

Variables: The Building Blocks of Research

A variable represents something that can change from person to person or situation to situation and is of interest to researchers.
Measured variables are aspects like height or braking time, observed and recorded numerically.
Manipulated variables are controlled by the researcher by assigning different participants to different levels of the variable.
Manipulated variables are only used in experiments.

Operationalizing Measured Variables

Operationalizing a measured variable involves converting it into a number.
Self-report involves asking people to describe themselves on a scale.
Direct observation involves counting behaviors or recording time.
Researchers can use technology to operationalize variables that are not easily observable.
The choice of how to operationalize a variable is often based on practical considerations.

Surveys: Descriptive Research Based on Self-Report

Descriptive research focuses on one variable at a time with the goal of describing what is typical.
Descriptive research based on self-report typically involves surveys.
Surveys provide concise summaries of a large number of people.
A sample refers to the group of people participating in the research.
Random sampling ensures the sample can be generalized to the population of interest.

Descriptive Research Based on Naturalistic Observations and Case Studies

Naturalistic observation involves observing animals or people in their natural environments without interference.
The goal of naturalistic observation is to observe behavior without influencing it.
Naturalistic observation can be a good measure of behavior because people may not accurately self-report their actions.
A case study is similar to naturalistic observation but focuses on a single individual or a very small group due to the rarity of their behaviors.

Correlational research measures two or more variables to understand the relationship between them.
Scatterplots display data from a correlational study, with each dot representing a participant.
The x-axis represents one variable (explanatory), and the y-axis represents another variable (response).
Positive correlation means as x increases, y increases.
Negative correlation means as x increases, y decreases.
Zero correlation means there is no systematic relationship between the two variables.

Correlations Reveal Relationships but Are Not Enough to Support Causal Claims

A stronger correlation implies better prediction.
However, correlation does not allow us to conclude that one variable causes the other.
To establish a causal link between two variables, three criteria must be met:
- The two variables must be correlated.
- We must know which variable came first in time.
- There must be no reasonable alternative explanations for the pattern.
The third-variable problem refers to a scenario where a correlation between two variables is explained by the influence of a third variable.

Experimental Research: Manipulating a Causal Variable to Observe Its Effect

Experimental research allows researchers to support causal statements such as "alcohol leads to aggression" or "feeling wealthy reduces generosity."
The researcher manipulates the variable believed to be causal and assesses its effect on one or more measured variables.
Participants are assigned to different levels of the variable (e.g., taking a drug or not taking a drug).
The independent variable is the hypothesized cause.
The dependent variable is the hypothesized effect, which is measured.

Random Assignment vs. Random Sampling

"Random" implies selection or assignment without bias.
Random sampling is a method for selecting participants who will be in a study.
Every person in the population of interest has an equal chance of being selected.
Random sampling can be used in surveys, observational studies, correlational studies, and experiments.
Random assignment is a method for assigning participants to different levels of the independent variable.
Random assignment is only used in experiments.
Each person in the study has an equal chance of being assigned to one experimental condition or another.
Random assignment allows researchers to assume that participants are similar on average at the beginning of the study.

Comparing and Contrasting Different Methods

Researchers might start with a descriptive study to identify what is typical, then move to a correlational method to establish relationships between variables, and finally use controlled experiments to establish causation.

Assessing Construct Validity: How Well Were the Variables Operationalized?

To assess construct validity, researchers examine how well the operationalizations in a study capture the variables of interest.
They ask questions like: What questionnaire was used? Which behaviors were observed?
Reliability refers to the consistency of a measure when administered repeatedly.
Researchers should also assess how well the independent variable was manipulated.

Assessing External Validity: Are the People Studied Representative of a Broader Population?

External validity refers to the generalizability of the study's findings to the population of interest.
Random sampling increases external validity.
Researchers also consider whether the results from one population of interest can be generalized to another.

Assessing Internal Validity: Can We Rule Out Most Plausible Alternative Explanations?

Internal validity refers to the ability to rule out other plausible explanations for the results.
Internal validity is higher in experiments than in correlational studies.
Sometimes, experiments are confounded, meaning the experimental groups accidentally differ on more than just the independent variable.
Confounds can jeopardize internal validity because they become alternative explanations for the findings.

Using Data to Describe People: Central Tendency and Standard Deviation

Descriptive statistics summarize participant responses in terms of what is most typical and the variability of responses.
A frequency distribution is a bar graph showing the distribution of possible scores on a variable.
The x-axis lists possible scores, and the y-axis represents the number of people who achieved each score.
There are three ways to describe central tendency:
- The mean is the average.
- The median is the middle value.
- The mode is the most common value.
Measures of variability include:
- The standard deviation indicates how much a set of scores varies around its mean.
- It is calculated by finding the distance between each individual score and the mean and averaging these distances.

Statistical Significance

Descriptive statistics summarize data from a study.
Effect sizes describe the strength of a correlation or the difference between groups in an experiment.
Inferential statistics are used to infer what is true about a broader population based on a sample.
Statistical significance testing is used to estimate whether results obtained in a sample are likely to have come from a particular population.
If a sample is randomly selected, it is assumed to be a good estimate of the rest of the population.
The null hypothesis assumes there is no relationship between variables.
Null hypothesis significance testing assumes there is no significant effect.
Researchers reject the null hypothesis if the sample's result is unlikely to have come from a population where no effect is present.
This means the observed effect is statistically significant.
A larger effect size (strong correlation or large group difference) makes statistical significance more likely.
Meta-analysis involves averaging results from multiple studies that tested the same variables to estimate the overall effect size.

Replication and High-Quality Science

Replication is crucial for validating scientific findings.
A study’s results are more likely to be trustworthy if they can be replicated by independent researchers.

Ethical Principles for Research with Humans

Researchers must ensure that participants are treated ethically.
Informed consent is crucial, meaning participants must understand the study’s procedures and risks before agreeing to participate.
Confidentiality is important, ensuring that participants' information is kept private.
Debriefing is a process to inform participants about the study's true purpose and to address any harm caused by the research.

Ethical Principles for Research with Animals

Researchers must adhere to strict ethical guidelines when conducting research with animals to minimize harm and distress.
Three key principles guide this research:
- Replacement: researchers should use alternatives to animals if possible.
- Refinement: researchers should modify procedures to minimize animal distress.
- Reduction: researchers should use the fewest possible animal subjects.

Limits of Intuition and Experience

Our intuitions are often biased because we tend to be overconfident in what we know and how well we understand events.
Our biased intuitions tend to discount cases that don’t match what we think.

The Scientific Method: Testing Theories with Data

The theory–data cycle involves developing a theory about what people do and collecting data that can be compared with the theory.
Data can either confirm or disconfirm a theory.
A hypothesis is a prediction about what will happen, based on a theory.
Data are observations gathered in a study, usually in numerical form, collected from people at certain times or in certain situations.
Replication occurs when a study has been conducted more than once on a new sample of participants and the same results were found.
Scientists share their scientific research in specialized scientific publications called journals.
The publication process involves peer review, where other scientists who are experts in that area of research identify the manuscript’s virtues and flaws.

Variables: The Building Blocks of Research

A variable is something of interest that can vary from person to person or situation to situation.
Measured variables are observed and recorded in some numeric form, such as height or braking time.
Manipulated variables are controlled by the researcher by assigning different participants to different levels of that variable, for example, intoxication.
Manipulated variables are only used in experiments.

Operationalizing Measured Variables

Operationalizing a measured variable means turning a variable into a number.
Self-report requires people to describe themselves on a scale.
Direct observation involves counting how many times people do a behavior or recording the time spent performing a behavior.
Researchers can rely on technology to operationalize variables not easily observable such as levels of intoxication and brain activation.

Surveys: Descriptive Research Based on Self-Report

Descriptive research focuses on one measured variable at a time with the goal of describing what is typical.
Surveys are a form of descriptive research based on self-report.
Survey research provides concise summaries on a lot of people.
A sample is a group of people participating in research.
Random sampling ensures we can generalize the sample to the full population of interest.
Samples are part of a larger group, which is the population of interest.
Surveys tell scientists what people are doing, not why they are doing it.

Descriptive Research Based on Naturalistic Observations and Case Studies

Naturalistic observation involves psychologists observing the behavior of animals or people in their normal, everyday worlds and environments.
The goal of naturalistic observation is to observe without interfering with their usual behavior.
Naturalistic observation can be a good measure of behavior because people may not always accurately self-report what they do.
A case study is a naturalistic observation conducted on only one individual or a very small group of people at a time because it is so rare.

Correlational research involves measuring two or more variables to understand the research between them.
Data from a correlational study is presented on a scatterplot.
Each dot on a scatterplot represents a study participant.
The x-axis represents one variable (explanatory), and the y-axis represents another variable (response).
A positive correlation occurs when x goes up, and y goes up.
A negative correlation occurs when x goes up, and y goes down.
A zero correlation occurs when there is no systematic relationship between two measured variables.

Correlations Reveal Relationships but Are Not Enough to Support Causal Claims

The stronger the correlation the better the prediction of one variable from the other.
Correlation does not allow researchers to conclude that one variable causes another.
To be convinced that one variable causes another three criteria must be met:
- The two variables must be correlated.
- Researchers must know for certain which variable came first in time.
- There must be no reasonable alternative explanations for the pattern.

Experimental Research: Manipulating a Causal Variable to Observe Its Effect

Experimental research is conducted in a way that can support causal statements.
The researcher manipulates a variable that is hypothesized to be causal and assesses the effect of that manipulation on one or more measured variables.
The independent variable is the hypothesized cause.
The dependent variable is the measured variable; the hypothesized effect.
Random assignment is a procedure used in experimental research.
Random assignment allows researchers to assume that people in each group are similar on average at the beginning of the study.
An experimental group is the group where the active ingredient or treatment is present.
A control group is the group in which the active ingredient or treatment is absent.
Ideally, control and experimental groups have the same experience during the day, with the exception of the one variable being manipulated.

Placebo Condition

Participants in both conditions should think they are being manipulated.
A placebo condition helps researchers separate physiological effects from people’s expectations.

Random Assignment vs Random Sampling

Random means something selected or assigned without any bias.
Random sampling is a method for selecting participants who will be in a study.
Every person in the population of interest has an equal chance of being selected for random sampling.
Random sampling can be used in a survey, observational study, correlational study, or experiment.
Random assignment is a method to assign participants to different levels of the independent variable.
Random assignment is only used in experiments.
Each person in the study has an equal chance of being in one experimental condition or another.

Comparing and Contrasting Different Methods

Researchers may start with a descriptive study to find out what is typical, then move to a correlational method to establish relationships between variables, then finally use controlled experiments to establish causation.

Assessing Construct Validity: How Well Were the Variables Operationalized?

Construct validity refers to how well a variable has been manipulated.
Researchers ask how accurately the operationalizations used in a study capture the variables of interest.
The question is what questionnaire did they use, which behaviors did they observe?
Reliability refers to the degree to which a measure yields constant results each time it is administered.
How well was the independent variable manipulated?

Assessing External Validity: Are the People Studied Representative of a Broader Population?

External validity refers to whether the study can generalize to the population of interest.
Random sampling helps establish external validity.
Researchers need to consider whether the results from their specific population of interest can generalize to a broader population of interest.

Assessing Internal Validity: Can We Rule Out Most Plausible Alternative Explanations?

Internal validity refers to the ability to rule out most plausible alternative explanations.
Studies with high internal validity are experiments, rather than correlational studies.
Sometimes experiments are confounded, which means the experimental groups accidentally differ on more than just the independent variable.
Poor internal validity occurs because confounds become alternative explanations of the study’s findings.

Using Data to Describe People: Central Tendency and Standard Deviation

Descriptive statistics summarize participants’ differing responses in terms of what was most typical and how much people’s responses varied from the average.
A frequency distribution is a bar graph in which possible scores on a variable are listed on the x-axis from lowest to highest, and the total number of people who got each score is plotted on the y-axis.
There are three ways to describe central tendency:
- Mean: The average.
- Median: The middle value.
- Mode: The most common value.
Measures of variability:
- Standard deviation indicates how much a batch of scores varies around its mean.

Statistical Significance

Descriptive statistics summarize a batch of scores from a study.
Effect sizes describe the strength of a correlation, or the degree of difference between groups in an experiment.
Inferential statistics use a sample to infer what is true about a broader population.
Statistical significance testing uses rules of logic and probability to estimate whether results obtained in a sample came from a particular population.
If the sample is randomly selected, researchers assume the sample is a good estimate of the rest of the population of interest.
The null hypothesis is the assumption that there is no relationship between variables.
Null hypothesis significance testing assumes nothing is going on (no significant effect).
Researchers reject the null hypothesis if the sample’s results only rarely come from the null hypothesis population (reject that nothing is going on, which means something is going on).
The results of a sample would happen fewer than 5 percent of the time if the null hypothesis is true (p < 0.05).
When researchers reject the null hypothesis the result is statistically significant.

Replication and High Quality Science

Replication refers to conducting a study more than once to see if the results are consistent.
Replication is critical for establishing the reliability of scientific findings.

Ethical Principles for Research with Humans

Informed consent: Participants must be informed of the nature of the study and the potential risks and benefits before they agree to participate.
Privacy and confidentiality: Participants’ responses must remain confidential and protected from unauthorized disclosure.
Deception: Deception may be used in research if it is justified by the potential benefits to science and if the participants are debriefed about the deception after the study.

Ethical Principles for Research with Animals

Replacement: Researchers should use alternatives to using animals in research when possible, such as computer simulations.
Refinement: Researchers should modify experimental procedures to minimize animal distress.
Reduction: Researchers should adopt experimental designs that require the fewest animal subjects possible.

Limits of Intuition and Experience

Often feel like our intuitions are correct because we are overconfident in our knowledge and understanding of events.
Tend to discount cases that don't match our own intuition.

The Scientific Method: Testing Theories with Data

Theories about people’s behaviours are developed and then tested against data.
Data either supports or refutes the theory.
Hypothesis is a prediction based on the theory.
Data represents observations from a study and are often in numerical form, which can be collected from people at different times or in different situations.
Replicating a study involves repeating it multiple times on different samples of participants to ensure similar results.
Scientific results are often shared in journals, which are specialized scientific publications that undergo peer review, meaning other experts evaluate the manuscript's strengths and weaknesses.

Variables: The Building Blocks of Research

Variable: Something of interest that can vary from person to person or situation to situation.
Measured variable: Can be observed and recorded in a numeric form, such as height or time.
Manipulated variable: Levels are controlled by the researcher, assigning different participants to different levels of the variable. For example, the researcher could manipulate the level of intoxication by assigning participants to drink either alcohol or a non-alcoholic beverage. This is only used in experiments.

Operationalizing Measured Variables

Operationalizing a measured variable involves converting it into a number.
Self-report: Asking people to describe themselves on a scale, such as from 0 to 10.
Direct observation: Counting the number of times someone performs a behavior or recording the time spent doing it.
Researchers can use technology to operationalize variables which are not easily observable, such as using a blood sample to measure intoxication levels or analyzing brain activity via fMRI.
The choice on how to operationalize depends on practical reasons.

Surveys: Descriptive Research Based on Self-Report

Descriptive research focuses on a single variable at a time, aiming to describe what is typical.
Surveys use self-report to gather information from a group of individuals.
Surveys provide summaries of data gathered from a large number of people.
Sample: A group of people who participate in a study.
Random sampling: Ensures that the sample can be generalized to the full population of interest. This means that each person in the population has an equal chance of being selected.
Surveys tell scientists what people are doing but not why they are doing it.

Descriptive Research Based on Naturalistic Observations and Case Studies

Naturalistic observation: Observing the behavior of animals or people in their normal environments without interfering with their usual behavior.
Case study: Naturalistic observation focused on one individual, or a small group, often because the behavior is rare.

Correlational research involves measuring two or more variables to see if there is a relationship between them.
Data for a correlational study is visualized using a scatterplot.
Scatterplot: Each dot represents a participant in the study.
The X-axis reflects one variable (explanatory), and the Y-axis reflects another (response).
Positive correlation: As X increases, Y increases.
Negative correlation: As X increases, Y decreases.
Zero correlation: No systematic relationship between the two variables.

Correlations Reveal Relationships but Are Not Enough to Support Causal Claims

The stronger the correlation, the better the prediction, but this does not imply causation between the two variables.
Example: Observing more aggression among wives in men who are dependent on alcohol does not mean alcohol causes aggression.
To establish causation, it is necessary to meet three criteria:
- The two variables must be correlated.
- We must know which variable comes first in time.
- There should be no other reasonable alternative explanations for the pattern.
The third variable problem: A correlation between two variables may be explained by the influence of a third variable.

Experimental Research: Manipulating a Causal Variable to Observe Its Effect

Experimental research is designed to support causal statements, such as "alcohol leads to aggression" or "feeling wealthy reduces generosity."
The researcher manipulates a variable believed to be the cause and then assesses the effects on one or more measured variables.
Independent variable: The hypothesized cause.
Dependent variable: The measured variable, representing the hypothesized effect.
Random assignment: A random method of assigning participants to different levels of the independent variable. This ensures that, on average, the participants in each group are similar at the beginning of the study.
Experimental group: The group that receives the active ingredient or treatment.
Control group: The group that does not receive the active ingredient or treatment.
Ideally, the control and experimental groups experience the same conditions during the study, except for the variable being manipulated.
It is important to keep the participants blind to the treatment they are receiving (placebo effect) to help researchers distinguish physiological effects from expectations.

Random Assignment vs Random Sampling

Random means something selected or assigned without any bias.
Random sampling is used to select participants for a study.
Each person in the population of interest has an equal chance of being selected.
Random sampling can be used in surveys, observational studies, correlational studies, or experiments.
Random assignment is specifically used in experiments to assign people to different levels of the independent variable.
Each person in the study has an equal chance of being assigned to one experimental condition or another.

Comparing and Contrasting Different Methods

Researchers may start with a descriptive study to explore what is typical. Then, they may pursue a correlational study to identify relationships between variables, followed by controlled experiments to establish causation.

Asessing Construct Validity: How Well Were the Variables Operationalized?

Construct validity: Measures how well a variable has been manipulated.
To determine construct validity, ask:
- How accurately do the operationalizations capture the variables of interest?
- What questionnaire was used?
- What behaviors were observed?
Reliability: Measures how consistent a measure is and whether it yields similar results each time it is administered.
Determine how well the independent variable was manipulated.

Assessing External Validity: Are The People Studied Representative of the Broader Population?

External validity: Measures whether the study can be generalized to the population of interest.
Consider whether random sampling was used.
Determine if results from one population can be generalized to other populations.

Asessing Internal Validity: Can We Rule Out Most Plausible Alternative Explanations?

Internal validity: Measures how well the study can rule out alternative explanations for the results.
Consider whether the study is an experiment rather than a correlational study.
A confound occurs when experimental groups unintentionally differ on more than just the independent variable.
Poor internal validity makes confounds become alternative explanations.

Using Data to Describe People: Central Tendency and Standard Deviation

Descriptive statistics: Summarize participants' responses in terms of typicality and variation.
Frequency distribution: A bar graph that shows the frequency of each possible score on a variable.
There are three ways to describe central tendency:
- Mean: The average.
- Median: The middle value.
- Mode: The most common value (the one that occurs the most times).
Measures of variability:
- Standard deviation: Measures how much a set of scores varies around the mean. It is calculated by finding the average distance between each individual score and the mean.
Measures of effect size
- r: Correlation coefficient
- d: Standard deviation

Statistical Significance

Descriptive statistics only summarize the data from the study; they don’t tell us if those results apply to other participants or situations.
Effect size (r and d): Describes the strength of a correlation or the difference between groups in an experiment.
Inferential statistics: Use a sample to infer what is true about a larger population.
Statistical significance testing: Uses rules of logic and probability to estimate whether the results obtained in a sample came from a particular population, allowing researchers to decide if the results represent a real effect or a fluke.
Null hypothesis: Assumes there is no relationship between variables.
Null hypothesis significance testing: Assumes nothing is happening (no significant effect).
Researchers reject the null hypothesis if the sample's result is unlikely to happen under the null hypothesis (meaning that there is something going on).
- The results would happen less than 5% of the time if the null hypothesis is true.
- p < 0.05
If the researcher rejects the null hypothesis, the result is statistically significant.
When the effect size is large (strong correlation or large group difference), it is more likely to be statistically significant.
Meta-analysis: Combines the results of multiple studies to determine an overall effect size, offering a more robust conclusion about the relationship between the variables.

Replication and High Quality Science

Replication: Key test of scientific quality.
A study that shows an unlikely result must be replicated to confirm the findings.

Ethical Principles for Research with Humans

Informed consent: Participants must understand the study's risks and benefits before agreeing to participate.
Confidentiality: All individual data must be kept private and confidential.
Deception: Deception is only permissible when necessary and is justified by the potential benefits of the research. In these cases, participants must be informed of the deception after the experiment has been completed.
Debriefing: Participants must be told the true purpose of the research after it is completed.
Research ethics boards: These review and approve all research involving human participants to ensure ethical guidelines are followed.

Ethical Principles for Research with Animals

Replacement: Use alternatives to animals in research whenever possible, such as computer simulations.
Refinement: Modify experimental procedures to minimize animal distress.
Reduction: Use the fewest animal subjects possible in research designs.

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Description

Explore the limits of intuition and the scientific method in psychology. Understand how to test theories, the importance of variables, and the role of data in confirming or disproving hypotheses. This quiz will challenge your grasp of core psychological research principles.