Null Result
In experimental research, a null result occurs when the collected data reveal no statistically significant effect of the manipulation of the independent variable on the dependent variable.
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Research Methods in Psychology - 4th American Edition @ KPU
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A social psychologist wants to determine if the number of bystanders present during an emergency affects how long it takes for an individual to help. The psychologist stages an emergency in a public space and systematically varies whether there are one, three, or ten other people present. The researcher then measures the time it takes for a participant to intervene and offer assistance. In this experiment, what is the dependent variable?
Example of an Experiment: Note-Taking Method and Learning Performance
Extraneous Variable
Time Series
Confounding Variable
Internal Validity
Null Result
Non-Experimental Research
In an experimental study, which of the following best describes the dependent variable?
In a psychological experiment investigating whether a new mnemonic technique improves memory recall, the students' memory recall scores represent the dependent variable.
Match each psychological research scenario with the specific dependent variable that would be measured to evaluate the presumed effect of the study's conditions.
A researcher investigates whether practicing mindfulness for ten minutes a day reduces anxiety scores on a standardized test. Arrange the logical steps for analyzing the role of the dependent variable in this investigation.
A researcher evaluates whether 'heart rate' or 'self-reported anxiety' is a more valid measure of the presumed effect in a study on stress. This judgment specifically addresses the quality and appropriateness of the ________ variable.
Suppose you are constructing an experimental protocol to investigate if 'ambient peppermint scent' improves 'cognitive focus' during a repetitive task. To create a valid dependent variable that measures the presumed effect of the scent, which of the following measurement strategies should you propose?
In a psychological experiment, the dependent variable is the factor that the researcher actively manipulates to determine its causal effect.
Match each core aspect of a dependent variable in a psychological experiment with the statement that best describes its function or behavior.
A researcher randomly assigns participants to either a quiet room or a noisy room and asks them to study a list of 30 vocabulary words for 10 minutes. Afterward, all participants complete a written recall test. The researcher records how many words each participant correctly recalled. In this experiment, the number of words correctly recalled is the _____, because it is the factor measured to evaluate whether the manipulation of the environmental condition produced a change.
A researcher proposes using 'number of errors made on a 10-minute proofreading task' as the dependent variable in a study on whether mental fatigue (induced by 60 minutes of continuous cognitive work) impairs attention. Arrange the following evaluative steps in the logical order a researcher should follow to determine whether this dependent variable is appropriate for the study.
Example of an Experiment: Note-Taking Method and Learning Performance
Functional Relationship Between Independent and Dependent Variables
A researcher conducts a study to determine if the amount of sleep affects problem-solving skills. One group of participants is allowed to sleep for eight hours, while a second group is only allowed to sleep for four hours. The next morning, both groups are given the same set of puzzles to solve, and the researcher records how many puzzles each participant completes correctly. In this study, what is the independent variable?
Identifying Experimental Variables
Extraneous Variable
Treatment
Non-Experimental Research
Non-Manipulated Independent Variable
Operational Definition
Experimental Manipulation
Experimental Condition
Internal Validity
Manipulation Check
Null Result
In an experimental research study, how is an independent variable defined?
A researcher conducts an experiment to determine if a new cognitive exercise improves memory retention. They have one group practice the exercise daily while a second group does not, and then they measure both groups' memory test scores. In this study, the memory test scores represent the independent variable.
Match each psychology study description to the specific factor that serves as the independent variable in that research scenario.
A researcher is investigating how anxiety affects cognitive performance. Arrange the following methods of operationalizing the Independent Variable (IV) from the approach that provides the highest degree of internal validity (strongest causal evidence) to the approach that provides the lowest degree.
In a factorial research design investigating how both lighting conditions (bright vs. dim) and participant age (young vs. old) affect visual search speed, a researcher classifies both 'lighting' and 'age' as _____ variables because they are both hypothesized to be causes of the variation in search speed.
According to the definition of experimental research, what is the role of an independent variable in a cause-and-effect relationship?
True or False: In psychological research, an independent variable must always be manipulated by the researcher and can never simply be measured.
Match each research design scenario to the correct status of its independent variable (IV) based on the study's design.
Active Manipulation in Experiments
Treatment
Experimental Condition
Manipulation Check
Null Result
In an experiment, what does it mean to manipulate an independent variable?
A researcher studying the effect of sleep deprivation on memory assigns one group of participants to sleep for 8 hours and a second group to sleep for only 4 hours, then measures both groups' recall scores. This procedure qualifies as experimental manipulation of the independent variable.
A researcher is conducting an experiment to see how different types of feedback affect student motivation. Match each action taken by the researcher to the specific component of experimental manipulation it represents.
A researcher is investigating how 'lighting intensity' affects student focus. To ensure the study utilizes a systematic change of the lighting levels across groups, the researcher must follow a specific logical structure. Arrange the following actions in the order required to correctly implement this process.
A researcher is developing a novel experiment to investigate the causal effect of 'visual complexity' on 'cognitive load'. To fulfill the requirement of experimental manipulation, which of the following original research protocols should the researcher create?
In a psychological experiment, manipulating an independent variable can only be achieved by exposing different groups of participants to different levels of that variable.
A researcher claims to have discovered a cause-and-effect relationship by comparing the focus levels of students who naturally drink coffee to those who do not. To evaluate the validity of this claim, a critic would argue that the study lacks a(n) _____ of the factor being studied. Without systematically changing which participants receive which amount of coffee, the researcher cannot rule out pre-existing differences as the true cause of the results.
Match each research scenario or experimental action to the specific aspect of experimental manipulation it applies.
A researcher measures the attention span of participants who naturally choose to drink coffee compared to those who do not. Because the researcher did not systematically change the caffeine levels, this study lacks _____, which is a fundamental requirement of an experiment.
Order the steps of designing, executing, and evaluating a study with an experimental manipulation from the first step to the final step.
Learn After
Interpreting Null Results with Manipulation Checks
In experimental research, what does a null result indicate?
A researcher investigates whether a specific exercise program reduces stress levels. After comparing the groups, the researcher finds that the difference in stress scores is not statistically significant. This outcome is correctly described as a null result.
A cognitive psychologist conducts an experiment to determine if wearing blue-tinted glasses improves reading speed. After collecting data from a group wearing the glasses and a group wearing clear lenses, the psychologist finds that both groups read at an average of 250 words per minute, and the difference is not statistically significant. In research terminology, this outcome is specifically referred to as a(n) ________.
A psychologist conducts an experiment to see if a 'citrus scent' improves 'test scores' but obtains a null result (no statistically significant difference). To analyze why this happened, the researcher investigates several possibilities. Match each potential explanation for the null result with the specific experimental scenario it describes.
A researcher concludes that a new cognitive therapy is ineffective after obtaining a null result (no statistically significant difference). To evaluate the validity of this conclusion, the researcher must rule out potential methodological errors. Arrange the following steps in the logical order required to perform this critical evaluation.
Imagine you are designing a research study to demonstrate the occurrence of a null result for a teaching lab. You decide to investigate whether listening to 'nature sounds' affects puzzle-solving speed. Which of the following experimental designs would you create to most likely produce a null result?
In experimental research, a null result is defined as an outcome where the independent variable has a statistically significant, but extremely small, effect on the dependent variable.
An experimenter tests whether daily use of a new studying app (0 hours vs. 2 hours) affects final exam scores. The analysis reveals no statistically significant difference in exam scores between the two groups. Match each element of this study to the corresponding research methods concept.
When an experiment yields a null result, a researcher can determine whether the outcome is due to a real absence of an effect or a failure in the experimental setup by analyzing a(n) _____.
A researcher obtains a null result in an experiment testing a new memory drug. Place the steps for evaluating the validity of this null result in the correct logical sequence, starting with verification of the manipulation.