Variables are crucial part of an eye tracking experiment. A change is anything the can readjust or it is in changed. In various other words, the is any factor that can be manipulated, regulated for, or measured in an experiment.Experiments contain different species of variables. Us will existing you with several of the main types of experimental variables, their definitions and give you examples containing all variable types.

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Types of experimental variables:

Independent variables (IV): These are the factors or conditions that friend manipulate in an experiment. Your hypothesis is the this variable reasons a direct effect ~ above the dependency variable.Dependent variables (DV): These are the variable that you watch or measure. As you vary your independent variable you clock what wake up to her dependent variable.

Extraneous variable: one extraneous varable is any kind of extra variable that may affect the result of one experiment, even though it is no the emphasis of the experiment. Ideally, these variables won’t affect the conclusions attracted from the outcomes as a careful experimental design should equally spread out influence throughout your check conditions and also stimuli.Nevertheless, extraneous variables should constantly be considered and also controlled when possible as they may present unwanted sports in her data. In this case, you should tweak her design and also procedure to be able to keep the variation constant or find a strategy to monitor its influence (constant or controlled variables).All experiments have extraneous variables. Right here are some examples of different species of extraneous variables:aspects that the setting where the data arsenal will take place, e.g., room temperature, background noise level, light levels;differences in participant attributes (participant variables); andtest operator, or experimenter habits during the test, i.e., their instructions to the test participants space not constant or they give unintentional hints of the score of the experiment come the participants.

Figure 2. Display screens the effect of extraneous variables on the relationship in between the independent and also dependent variables.

controlled (or constant) variables: space extraneous variables the you control to keep continuous or controlled for during the course of the experiment, together they may have an impact on her dependent variables together well.Participant variables: Participant variables have the right to be characterized as the different individual attributes that may influence how a participant responds in an experiment. Instances of participant variables include gender, age, ethnicity, socioeconomic status, literacy status, mood, clinical diagnosis etc.Stimulus variables: this are particular features of her stimulus or group of stimuli the are part of the paper definition in i m sorry the actions occurs. These are often an expression that or a subset of your independent variables and also covariates. Examples include the number of items, item category, stimulus crowdedness, color, brightness, contrast, etc.

Operationalizing variables

Before you begin your experiment, you need to have a clear an interpretation of, and also strategy for, exactly how each variable will be measured and recorded. This process is referred to as variable operationalization.

For example, you are interested in studying perspectives towards food, intuitive attention, and food choice. In your an initial study, your objective is to inspection “the impact of personal health purposes on visual fist to different food groups”.

The very first part of her objective, “the impact of an individual health goals…”, includes an elevation variable. Come operationalize it you need to ask yourself the adhering to questions: What is a an individual health goal? can you quantify and also measure it? can you rest it down into distinct categories? just how will friend collect and also record the value? as result of the nature of this term, her variable will most most likely be composed of two or an ext categories (e.g. Lose weight, save weight, get weight etc.) and also its value recorded by way of a questionnaire or interview. An alert that in this example, the independent variable is additionally an intrinsic attribute that a participant and also thus certain to that individual, as a result, this variable can also be classified together a participant variable.

The next part of your examine objective “…on visual attention to various food groups”, contains your dependency variable. Once again, you will need to ask yourself the following questions: What is visual attention? how do i measure it? just how is food grouped? exactly how will we stand for the different groups in the stimuli? Which grouping strategy is relevant to mine objective? The ax “visual attention to” can be operationalized into one or much more relevant visual habits measures that deserve to be quantified and also measured continuously. Because that example, eye tracking metrics like fixation duration, fixation count, and dwell time can administer you v information around the intuitive engagement and also bias towards various items in her stimulus. The “… various food groups” term will certainly most likely be operationalized together food species aggregated into categories (e.g. Vegetables, red meat, dairy) and also displayed on photo stimulus. Due to the fact that you room manipulating the content of the stimulus and also the manipulation affect the context in i beg your pardon the behavior occurs and the viewing habits itself, your stimulus categories will certainly be part of your set of live independence variables and simultaneously a stimulus variable.


Figure 3. Mirrors one possible outcome that the operationalization of the various variables in the example study. The objective of this study is to discover out what effect an individual health goals have actually on a person"s visual fist to different food groups.

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In the example above, the participant’s "current hunger state" is a factor that may influence visual behavior and attention bias. If a check participant ate their meal a lengthy time earlier and feels hungry, their attention may become focused ~ above high calorie food groups, even though they could normally not look come those food items as soon as they"re satisfied. If you decide to disregard it, it i do not care an extraneous variable in your experiment and also may influence the relationship between your independent and also dependent variable. On the other hand, if you decide to deal with it and also control for it, girlfriend will also have to operationalize it, e.g. You deserve to measure it together the elapsed time since the last meal. If you climate ask all your examine participants come eat a enjoy the meal within 1 hour before your test, this variable i do not care a regulated variable, together you try to standardize the level the hunger across your independent variable groups.