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Eye tracking is a behavioral research tool often used to answer research questions about various aspects of human behavior and cognition, such as visual attention, memory, or decision-making.
Here are some examples of research questions that can be addressed with eye tracking:
As illustrated above, research questions are too broad to answer in a controlled and systematic manner. Therefore, they require dissection into testable hypotheses. The hypothesis is the prediction about a possible outcome of an experiment where an independent variable is manipulated, and the corresponding change in a dependent variable will be observed. Researchers formulate hypotheses based on existing knowledge and then design experiments to either confirm or refute these hypotheses.
Factors or conditions an experimenter manipulates in an experiment. The hypothesis suggests that changing this variable causes a direct effect on the dependent variable.
Factor or condition observed or measured in response to manipulations in the independent variable.
Here are some examples of experiment hypothesis and its independent and dependent variables:
Type of movie clip (horror or neutral).
Saccades during memory encoding.
Blinking rate during the auditory stimulus
The perceived duration of the auditory stimulus.
Some additional types of variables are important to consider when designing an eye tracking experiment:
Factors or conditions that may affect the outcome of an experiment, even though they are not the primary independent or dependent variables. Extraneous variables may introduce unwanted bias in your data and lead to inaccurate conclusions. Extraneous variables can be controlled and uncontrolled.
In the experiment studying "The link between saccades and memory performance,” these are some extraneous variables to consider:
Different individual characteristics that may impact how a participant responds in an experiment. Examples of participant variables include gender, age, ethnicity, socioeconomic status, literacy status, mood, clinical diagnosis, and others.
Features of your stimulus or group of stimuli that are part of the context in which the behavior occurs. These are often an expression of or a subset of independent variables and covariates. Examples include the number of items, category, stimulus crowdedness, color, brightness, and contrast.
Before starting your experiment, it is essential to have a clear definition of and strategy for how each variable will be measured and recorded. This process is called variable operationalization. For your experiment investigating “The link between saccades and memory performance,” you will need to operationalize two primary variables:
The number of saccades refers to the count of rapid, ballistic eye movements that occur when an individual views a visual scene. Define what aspects of saccades you are interested in, for example – saccade amplitude toward AOIs, number of saccades, or scan path.
To manipulate the presence of saccades, you can introduce a stimulus variable – trials in which participants are asked to fixate on a screen during the entire stimulus viewing period. In this way, you can account for the effect of saccades on memory retrieval by comparing ”saccade trials” to ”fixation trials.” Learn more about different
types of eye movements.
To measure, record, and quantify various aspects of saccades and fixations, you can use eye tracking technology, such as eye tracking software and hardware.
Tobii eye trackers can capture eye movement data at up to 1200 Hz, and the
Tobii Pro Lab software simplifies the calculation and export of various eye tracking metrics.
Curious to learn more about eye tracking in scientific research? This white paper explains how eye tracking can provide insights into attention, memory, decision-making, problem-solving, and more.
Define what aspects of memory performance you want to quantify and the tasks you will use. Will you use recall tasks, recognition tasks, or retrieval? Variables related to the memory performance measurement might include:
SCIENCE WRITER, TOBII
As a science writer, I get to read peer-reviewed publications and write about the use of eye tracking in scientific research. I love discovering the new ways in which eye tracking advances our understanding of human cognition.
Advanced Screen simplifies the design of screen-based eye tracking studies for behavioral research and allows researchers to easily create and control complex experiments.
In this learn article, we will present how eye tracking technology has been used to study cognitive processes and the insights that these studies have generated.
Saccades, fixations, and other types of eye movements can be captured with eye tracking technology. Read about various types of eye movements and their function.