Variables are crucial part of one eye tracking experiment. A change is anything the can change or it is in changed. In various other words, it is any kind of factor that deserve to be manipulated, regulated for, or measure up in one experiment.Experiments save different types of variables. Us will existing you with some of the main species of experimental variables, your definitions and give you examples containing every variable types.

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Types of experimental variables:

Independent variables (IV): These space the determinants or problems that you manipulate in an experiment. Your theory is that this variable causes a direct effect ~ above the dependent variable.Dependent variables (DV): These space the factor that you observe or measure. Together you vary your independent change you watch what happens to her dependent variable.

Extraneous variable: one extraneous varable is any type of extra aspect that may influence the result of an experiment, also though the is not the focus of the experiment. Ideally, this variables won’t affect the conclusions attracted from the outcomes as a mindful experimental architecture should equally spread out influence throughout your check conditions and stimuli.Nevertheless, extraneous variables should always be considered and controlled when possible as castle may introduce unwanted variation in your data. In this case, you should tweak her design and also procedure to have the ability to keep the variation constant or find a strategy to screen its influence (constant or managed variables).All experiments have extraneous variables. Below are some examples of different species of extraneous variables:aspects that the setting where the data collection will take it place, e.g., room temperature, lift noise level, irradiate levels;differences in participant characteristics (participant variables); andtest operator, or experimenter habits during the test, i.e., their instructions to the check participants space not continuous or they provide unintentional hints of the goal of the experiment come the participants.

Figure 2. Displays the result of extraneous variables top top the relationship between the independent and also dependent variables.

regulated (or constant) variables: are extraneous variables the you control to keep consistent or controlled for during the course of the experiment, together they may have actually an result on your dependent variables together well.Participant variables: Participant variables have the right to be defined as the different individual qualities that may affect how a participant responds in one experiment. Instances of participant variables encompass gender, age, ethnicity, socioeconomic status, proficiency status, mood, clinical diagnosis etc.Stimulus variables: these are specific features of your stimulus or group of stimuli that are part of the paper definition in i beg your pardon the actions occurs. This are often an expression of or a subset of her independent variables and also covariates. Examples incorporate the number of items, article category, economic stimulation crowdedness, color, brightness, contrast, etc.

Operationalizing variables

Before you begin your experiment, you require to have actually a clear meaning of, and strategy for, exactly how each variable will be measured and recorded. This process is dubbed variable operationalization.

For example, you space interested in studying mindsets towards food, visual attention, and food choice. In your an initial study, your objective is to investigate “the effect of personal health purposes on visual attention to different food groups”.

The first part of her objective, “the effect of personal health goals…”, contains an elevation variable. Come operationalize it you should ask yourself the adhering to questions: What is a personal health goal? have the right to you quantify and measure it? can you break it down into unique categories? how will you collect and record that is value? because of the nature of this term, your variable will certainly most likely be composed of 2 or much more categories (e.g. Shed weight, store weight, acquire weight etc.) and also its value recorded by method of a questionnaire or interview. Notice that in this example, the independent variable is also an intrinsic attribute the a participant and thus specific to that individual, together a result, this variable can likewise be classified as a participant variable.

The next component of your examine objective “…on visual attention to different food groups”, has your dependency variable. Once again, friend will have to ask you yourself the adhering to questions: What is intuitive attention? just how do i measure it? how is food grouped? just how will we stand for the different groups in the stimuli? Which group strategy is appropriate to mine objective? The ax “visual fist to” can be operationalized into one or much more relevant visual behavior measures that can be quantified and also measured continuously. For example, eye tracking metrics favor fixation duration, continuous count, and also dwell time can carry out you v information around the intuitive engagement and bias towards different items in her stimulus. The “… different food groups” term will certainly most most likely be operationalized as food species aggregated into categories (e.g. Vegetables, red meat, dairy) and also displayed on photo stimulus. Because you space manipulating the contents of the stimulus and the manipulation affect the paper definition in which the behavior occurs as well as the viewing actions itself, her stimulus categories will certainly be part of your collection of live independence variables and simultaneously a stimulus variable.


Figure 3. Reflects one possible outcome the the operationalization that the various variables in the example study. The objective of this research is to find out what effect personal 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 also attention bias. If a test participant ate their enjoy the meal a long time back and feeling hungry, their fist may come to be focused ~ above high calorie food groups, also though they might normally not look come those food items once they"re satisfied. If you decision to ignore it, it becomes an extraneous variable in your experiment and also may influence the relationship in between your independent and also dependent variable. Top top the various other hand, if you decide to address it and control for it, girlfriend will additionally have to operationalize it, e.g. You can measure it as the elapsed time since the last meal. If you then ask all your research participants come eat a enjoy the meal within 1 hour before your test, this variable i do not care a regulated variable, together you shot to standardize the level the hunger throughout your independent variable groups.