Controlled ExperimentBy Dr. Saul McLeod, published 2019 Show
What is a controlled experiment? This is when a hypothesis is scientifically tested. In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. The researcher can operationalize (i.e. define) the variables being studied so they can be objectivity measured. The quantitative data can be analysed to see if there is a difference between the experimental group and control group. What is the control group in an experiment?What are extraneous variables in an experiment?
Why do scientists conduct controlled experiments? Scientists use controlled experiments because they allow for precise control of extraneous and independent variables. This allows a cause and effect relationship to be established. Controlled experiments also follow a standardised step by step procedure. This makes it easy another researcher to replicate the study. Key TerminologyExperimental GroupThe group being treated, or otherwise manipulated for the sake of the experiment. Control GroupThey receive no treatment and are used as a comparison group. Ecological validityThe degree to which an investigation represents real-life experiences. Experimenter effectsThese are the ways that the experimenter can accidentally influence the participant through their appearance or behavior. Demand characteristicsThe clues in an experiment that lead the participants to think they know what the researcher is looking for (e.g. experimenter’s body language). Independent variable (IV)Variable the experimenter manipulates (i.e. changes) – assumed to have a direct effect on the dependent variable. Dependent variable (DV)Variable the experimenter measures. This is the outcome (i.e. result) of a study. Extraneous variables (EV)All variables, which are not the independent variable, but could affect the results (DV) of the experiment. Extraneous variables should be controlled where possible. Confounding variablesVariable(s) that have affected the results (DV), apart from the IV. A confounding variable could be an extraneous variable that has not been controlled. Random AllocationRandomly allocating participants to independent variable conditions means that all participants should have an equal chance of taking part in each condition. The principle of random allocation is to avoid bias in the way the experiment is carried out and to limit the effects of participant variables. Order effectsChanges in participants’ performance due to their repeating the same or similar test more than once. Examples of order effects include: (i) practice effect: an improvement in performance on a task due to repetition, for example, because of familiarity with the task; (ii) fatigue effect: a decrease in performance of a task due to repetition, for example, because of boredom or tiredness. How to reference this article:How to reference this article:McLeod, S. A. (2019, Aug 12). Controlled Experiment Simply psychology: https://www.simplypsychology.org/controlled-experiment.html Home | About Us | Privacy Policy | Advertise | Contact Us Simply Psychology's content is for informational and educational purposes only. Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. © Simply Scholar Ltd - All rights reserved What are the features of a wellKey elements of a well-designed experiment. Ensure your experiment is unbiased.. Make sure your experiment is adequately powered.. Consider the range of applicability of your experiment.. Simplify your experiment.. Indicate the uncertainty in your results.. References and further reading.. What are the elements of a wellWhat are the components of experimental design? The components of experimental design are control, independent variable and dependent variable, constant variables, random assignment and manipulation. These are the components that also help you define if the experiment is valid.
What are the three key features of experimental design?In general, designs that are true experiments contain three key features: independent and dependent variables, pretesting and posttesting, and experimental and control groups. In a true experiment, the effect of an intervention is tested by comparing two groups.
What is a well controlled experiment?What characterizes a well-controlled experiment? A well-designed experiment is simple and easily replicated. It maintains strict control on all variables. The variables in the experiment are designed to prove or disprove a casual relationship between the independent variable and the dependent variable.
|