Name: using eye movements recorded in the visual world paradigm to explore the online processing of spoken language
Uploaded: 2018-10-13T12:30:00.000+00:00
Duration: 9 min 27 s
Description: Watch this Scientific Journal Video about Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language at JoVE.com

This research was supported by Science Foundation of Beijing Language and Cultural University under the Fundamental Research Funds for the Central Universities (Approval number 15YJ050003).

The author declares that he has no competing financial interests.

To conduct a visual world study, there are several critical steps to follow. First, researchers intend to deduce the interpretation of the auditorily presented language via participants&#39; eye movements in the visual world. Henceforth, in designing the layout of the visual stimuli, the properties of eye movements in a natural task that potentially affect participants&#39; eye movements should be controlled. The effect of the spoken language on participants&#39; eye movements can then be recognized. Second, acoustic cue...

Spoken language is a fast, ongoing information flow, which disappears right away. It is a challenge to experimentally study this temporal, rapidly change speech signal. Eye movements recorded in the visual world paradigm can be used to overcome this challenge. In a typical eye tracking study using the visual world paradigm, participants&#39; eye movements to pictures in a display or to real objects in a visual workspace are monitored as they listen to, or produce, spoken language depicting the contents of the visual world1,2,3,4. The basic logic, or the linking hypothesis, behind this paradigm is that comprehending or planning an utterance will (overtly or covertly) shift participants&#39; visual attention to a certain object in the visual world. This attention shift will have a high probability to initiate a saccadic eye movement to bring the attended area into the foveal vision. With this paradigm, researchers intend to determine at what temporal point, with respect to some acoustic landmark in the speech signal, a shift in the participant&#39;s visual attention occurs, as measured by a saccadic eye movement to an object or a picture in the visual world. When and where saccadic eye movements are launched in relation to the speech signal are then used to deduce the online language processing. The visual world paradigm can be used to study both the spoken language comprehension1,2 and production5,6. This methodological article will focus on comprehension studies. In a comprehension study using the visual world paradigm, participants&#39; eye movements on the visual display are monitored as they listen to the spoken utterances talking about the visual display.
Different eye tracking systems have been designed in history. The simplest, least expensive, and most portable system is just a normal video camera, which records an image of the participant&#39;s eyes. Eye movements are then manually coded through frame-by-frame examination of the video recording. However, the sampling rate of such an eye-tracker is relatively low, and the coding procedure is time consuming. Thus, a contemporary commercial eye tracking system normally uses optical sensors measuring the orientation of the eye in its orbit7,8,9. To understand how a contemporary commercial eye-tracking system works, the following points should be considered. First, to correctly measure the direction of the foveal vision, an infrared illuminator (normally with the wavelength around 780-880 nm) is normally laid along or off the optical axis of the camera, making the image of the pupil distinguishably brighter or darker than the surrounding iris. The image of the pupil and/or of the pupil corneal reflection (normally the first Purkinje image) is then used to calculate the orientation of the eye in its orbit. Second, the gaze location in the visual world is actually contingent not only on the eye orientation with respect to the head but also on the head orientation with respect to the visual world. To accurately infer the gaze of regard from the eye orientation, the light source and the camera of the eye-trackers either are fixed with respect to participants&#39; head (head-mounted eye-trackers) or are fixed with respect to the visual world (table-mounted or remote eye-trackers). Third, the participants&#39; head orientation must either be fixed with respect to the visual world or be computationally compensated if participants&#39; head is free to move. When a remote eye-tracker is used in a head-free-to-move mode, the participants&#39; head position is typically recorded by placing a small sticker on participants&#39; forehead. The head orientation is then computationally subtracted from the eye orientation to retrieve the gaze location in the visual world. Fourth, a calibration and a validation process are then required to map the orientation of the eye to the gaze of regard in the visual world. In the calibration process, participants&#39; fixation samples from known target points are recorded to map the raw eye data to gaze position in the visual world. In the validation process, participants are presented with the same target points as the calibration process. The difference existing between the computed fixation position from the calibrated results and the actual position of the fixated target in the visual world are then used to judge the accuracy of the calibration. To further reconfirm the accuracy of the mapping process, a drift check is normally applied on each trial, where a single fixation target is presented to participants to measure the difference between the computed fixation position&#160;and the actual position of the current target.
The primary data of a visual world study is a stream of gaze locations in the visual world recorded at the sampling rate of the eye-tracker, ranging over the whole or part of the trial duration. The dependent variable used in a visual world study is typically the proportion of samples that participants&#39; fixations are situated at certain spatial region in the visual world across a certain time window. To analyze the data, a time window has firstly to be selected, often referred to as periods of interest. The time window is typically time-locked to the presentation of some linguistic events in the auditory input. Furthermore, the visual world is also needed to split into several regions of interest (ROIs), each of which is associated with one or more objects. One such region contains the object corresponding to the correct comprehension of the spoken language, and thus&#160;is often called the target area. A typical way to visualize the data is a proportion-of-fixation plot, where at each bin in a time window, the proportion of samples with a look to each region of interest are averaged across participants and items.
Using the data obtained from a visual world study, different research questions can be answered: a) On the coarse-grain level, are participants&#39; eye movements in the visual world affected by different auditory linguistic input?&#160;b) If there is an effect, what is the trajectory of the effect over the course of the trial? Is it a linear effect or high-order effect?&#160;and c) If there is an effect, then on the fine-grain level, when is the earliest temporal point where such an effect emerges and how long does this effect last?
To statistically analyze the results, the following points should be considered. First, the response variable, i.e., proportions of fixations, is both below and above bounded (between 0 and 1), which will follow a multinomial distribution rather than a normal distribution. Henceforth, traditional statistical methods based on normal distribution such as t-test, ANOVA, and linear (mixed-effect) models10, cannot be directly utilized until the proportions have been transformed to unbounded variables such as with empirical logit formula11 or have been replaced with unbounded dependent variables such as Euclidean distance12. Statistical techniques that do not require the assumption of normal distribution such generalized linear (mixed-effect) models13 can also be used. Second, to explore the changing trajectory of the observed effect, a variable denoting the time-series has to be added into the model. This time-series variable is originally the eye-tracker&#8217;s sampling points realigned to the onset of the language input. Since the changing trajectory typically is not linear, a high-order polynomial function of the time-series is normally added into the (generalized) linear (mixed-effect) model, i.e., growth curve analyses14. Furthermore, participants&#8217; eye positions in the current sampling point is highly dependent on previous sampling point(s), especially when the recording frequency is high, resulting in the problem of autocorrelation. To reduce the autocorrelation between the adjacent sampling points, original data are often down-sampled or binned. In recent years, the generalized additive mixed effect models (GAMM) have also been used to tackle the autocorrelated errors12,15,16. The width of bins varies among different studies, ranging from several milliseconds to several hundred milliseconds. The narrowest bin a study can choose is restricted by the sampling rate of the eye tracker used in the specific study. For example, if an eye tracker has a sampling rate of 500 Hz, then the width of the time window cannot be smaller than 2 ms = 1000/500. Third, when a statistical analysis is repeatedly applied to each time bin of the periods of interest, the familywise error induced from these multiple comparisons should be tackled. As we described earlier, the trajectory analysis informs the researcher whether the effect observed on the coarse-grain level is linear with respect to the changing of the time, but does not show when the observed effect begins to emerge and how long the observed effect lasts. To determine the temporal position when the observed difference starts to diverge, and to figure out the duration of the temporal period that the observed effect lasts, a statistic analysis has to be repeatedly applied to each time bin. These multiple comparisons will introduce the so-called familywise error, no matter what statistical method is used. The familywise error is traditionally corrected with Bonferroni adjustment17. Recently, a method called nonparametric permutation test originally used in neuroimaging field18 has been applied to the visual word paradigm19 to control for the familywise error.
Researchers using the visual world paradigm intend to infer the comprehension of some spoken language from participants&#8217; eye movements in the visual world. To ensure the validity of this deduction, other factors that possibly influence the eye movements should be either ruled out or controlled. The following two factors are among the common ones that need to be considered. The first factor involves some systematic patterns in participants&#8217; explanatory fixations independent of the language input, such as the tendency to fixate on the top left quadrat of the visual world, and moving eyes in the horizontal direction being easier than in the vertical direction, etc.12,20 To make sure that the observed fixation patterns are related to the objects, not to the spatial locations where the objects are situated, the spatial positions of an object should be counterbalanced across different trials or across different participants. The second factor that might affect participants&#8217; eye movements is the basic image features of the objects in the visual world, such as luminance contrast, color and edge orientation, among others21. To diagnose this potential confounding, the visual display is normally presented prior to the onset of the spoken language or prior to the onset of the critical acoustic marker of the spoken language, for about 1000 ms. During the temporal period from the onset of the test image to the onset of the test audio, the language input or the disambiguation point of the language input has not been heard yet. Any difference observed between different conditions should be deduced to other confounding factors such as the visual display per se, rather than the language input. Henceforth, eye movements observed in this preview period provide a baseline for determining the effect of the linguistic input. This preview period also allows participants to get familiarized with the visual display, and to reduce the systematic bias of the explanatory fixations when the spoken language is presented.
To illustrate how a typical eye tracking study using the visual world paradigm is conducted, the following protocol describes an experiment adapted from L. Zhan&#160;17&#160;to explore the online processing of semantically complex statements, i.e., disjunctive statements (S1 or S2), conjunctive statements (S1 and S2), and but-statements (S1 but not-S2). In ordinary conservation, the information expressed by some utterances is actually stronger than its literal meaning. Disjunctive statements like Xiaoming&#39;s box contains a cow or a rooster are such utterances. Logically, the disjunctive statement is true as long as the two disjuncts Xiaoming&#39;s box contains a cow and Xiaoming&#39;s box contains a rooster are not both false. Therefore, the disjunctive statement is true when the two disjuncts are both true, where the corresponding conjunctive statement Xiaoming&#39;s box contains a cow and a rooster is also true. In ordinary conversation, however, hearing the disjunctive statement often suggests that the corresponding conjunctive statement is false (scalar implicature); and suggests that the truth values of the two disjuncts are unknown by the speaker (ignorance inference). Accounts in the literature differ in whether two inferences are grammatical or pragmatic processes22,23,24,25,26. The experiment shows how the visual world paradigm can be used to adjudicate between these accounts, by exploring the online processing of three complex statements.

<table><tbody><tr><td>Pixelmator</td><td>Pixelmator Team</td><td>http://www.pixelmator.com/pro/</td><td>image editing app</td></tr><tr><td>Praat</td><td>Open Sourse</td><td>http://www.fon.hum.uva.nl/praat/</td><td>Sound analyses and editting software</td></tr><tr><td>Eyelink 1000plus</td><td>SR-Research, Inc</td><td>https://www.sr-research.com/products/eyelink-1000-plus/</td><td>remote infrared eye tracker&amp;nbsp;</td></tr><tr><td>Experimental Builder</td><td>SR-Research, Inc</td><td>https://www.sr-research.com/experiment-builder/</td><td>eye tracker software&amp;nbsp;</td></tr><tr><td>Data Viewer</td><td>SR-Research, Inc</td><td>https://www.sr-research.com/data-viewer/</td><td>eye tracker software&amp;nbsp;</td></tr><tr><td>R</td><td>Open Sourse</td><td>https://www.r-project.org</td><td>free software environment for statistical computing and graphics</td></tr></tbody></table>

using eye movements recorded in the visual world paradigm to explore the online processing of spoken language

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded via an eye tracker as the participant produces or comprehends a spoken language describing the concurrent visual world. This paradigm has high versatility, as it can be used in a wide range of populations, including those who cannot read and/or who cannot overtly give their behavioral responses, such as preliterate children, elderly adults, and patients. More importantly, the paradigm is extremely sensitive to fine grained manipulations of the speech signal, and it can be used to study the online processing of most topics in language comprehension at multiple levels, such as the fine grained acoustic phonetic features, the properties of words, and the linguistic structures. The protocol described in this article illustrates how a typical visual world eye tracking study is conducted, with an example showing how the online processing of some semantically complex statements can be explored with the visual world paradigm.

Participants&#39; behavioral responses are summarized in Figure 4. As we described earlier, the correct response to a conjunctive statement (S1 and S2) is the big open box, such as Box A in Figure 1. The correct response to a but-statement (S1 but not S2) is the small open box containing the first mentioned animal, such as Box D in Figure 1. Critically, which box is chosen ...

Watch this Scientific Journal Video about Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language at JoVE.com

Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language

The visual world paradigm monitors participants' eye movements in the visual workspace as they are listening to or speaking a spoken language. This paradigm can be used to investigate the online processing of a wide range of psycholinguistic questions, including semantically complex statements, such as disjunctive statements.

In a typical eye tracking study using the visual world paradigm, participants' eye movements to objects or pictures in the visual workspace are recorded ...

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Research

JoVE Journal

Behavior

9.9K Views.  Beijing Language and Culture University. The visual world paradigm monitors participants' eye movements in the visual workspace as they are listening to or speaking a spoken language. This paradigm can be used to investigate the online processing of a wide range of psycholinguistic questions, including semantically complex statements, such as disjunctive statements.

Video: Using Eye Movements Recorded in the Visual World Paradigm to Explore the Online Processing of Spoken Language

Using Eye Movements to Evaluate the Cognitive Processes Involved in Text Comprehension

The present article describes how to use eye tracking methodologies to study the cognitive processes involved in text comprehension. Measuring eye movements during reading is one of the most precise methods for measuring moment-by-moment (online) processing demands during text comprehension. Cognitive processing demands are reflected by several aspects of eye movement behavior, such as fixation duration, number of fixations, and number of regressions (returning to prior parts of a text). Important properties of eye tracking equipment that researchers need to consider are described, including how frequently the eye position is measured (sampling rate), accuracy of determining eye position, how much head movement is allowed, and ease of use. Also described are properties of stimuli that influence eye movements that need to be controlled in studies of text comprehension, such as the position, frequency, and length of target words. Procedural recommendations related to preparing the participant, setting up and calibrating the equipment, and running a study are given. Representative results are presented to illustrate how data can be evaluated. Although the methodology is described in terms of reading comprehension, much of the information presented can be applied to any study in which participants read verbal stimuli.

The present article describes how to use eye tracking methodologies to study the cognitive processes involved in text comprehension. Descriptions of eye tracking equipment, how to develop experimental stimuli, and procedural recommendations are included. The information presented can be applied to most any study using verbal stimuli.

The present article describes how to use eye  tracking methodologies to study the cognitive processes involved in text  comprehension. Measuring eye ...

Methods to Test Visual Attention Online

Online data collection methods have particular appeal to behavioral scientists because they offer the promise of much larger and much more representative data samples than can typically be collected on college campuses. However, before such methods can be widely adopted, a number of technological challenges must be overcome &#8211; in particular in experiments where tight control over stimulus properties is necessary. Here we present methods for collecting performance data on two tests of visual attention. Both tests require control over the visual angle of the stimuli (which in turn requires knowledge of the viewing distance, monitor size, screen resolution, etc.) and the timing of the stimuli (as the tests involve either briefly flashed stimuli or stimuli that move at specific rates). Data collected on these tests from over 1,700 online participants were consistent with data collected in laboratory-based versions of the exact same tests. These results suggest that with proper care, timing/stimulus size dependent tasks can be deployed in web-based settings.

To replicate laboratory settings, online data collection methods for visual tasks require tight control over stimulus presentation. We outline methods for the use of a web application to collect performance data on two tests of visual attention.

Online data collection methods have particular appeal to behavioral scientists because they offer the promise of much larger and much more representative ...

VisualEyes: A Modular Software System for Oculomotor Experimentation

Eye movement studies have provided a strong foundation forming an understanding of how the brain acquires visual information in both the normal and dysfunctional brain.1 However, development of a platform to stimulate and store eye movements can require substantial programming, time and costs. Many systems do not offer the flexibility to program numerous stimuli for a variety of experimental needs. However, the VisualEyes System has a flexible architecture, allowing the operator to choose any background and foreground stimulus, program one or two screens for tandem or opposing eye movements and stimulate the left and right eye independently. This system can significantly reduce the programming development time needed to conduct an oculomotor study. The VisualEyes System will be discussed in three parts: 1) the oculomotor recording device to acquire eye movement responses, 2) the VisualEyes software written in LabView, to generate an array of stimuli and store responses as text files and 3) offline data analysis. Eye movements can be recorded by several types of instrumentation such as: a limbus tracking system, a sclera search coil, or a video image system. Typical eye movement stimuli such as saccadic steps, vergent ramps and vergent steps with the corresponding responses will be shown. In this video report, we demonstrate the flexibility of a system to create numerous visual stimuli and record eye movements that can be utilized by basic scientists and clinicians to study healthy as well as clinical populations.

Neural control and cognitive processes can be studied through eye movements. The VisualEyes software allows an operator to program stimuli on two computer screens independently using a simple, custom scripting language. The system can stimulate tandem eye movements (saccades and smooth pursuit) or opposing eye movements (vergence) or any combination.

Eye movement studies have provided a strong foundation forming an understanding of how the brain acquires visual information in both the normal and ...

Neuroscience

Recording Horizontal Saccade Performances Accurately in Neurological Patients Using Electro-oculogram

Electro-oculogram (EOG) has been widely used for clinical eye movement recording, especially horizontal saccades, although the video-oculography (VOG) has largely taken the place of it nowadays due to its higher spatial accuracy. However, there are situations in which EOG has clear advantages over VOG, e.g., subjects with narrow eye clefts or having cataract lenses, and patients with movement disorders. The present article shows that if properly implemented, EOG can achieve an accuracy almost as good as VOG with substantial stability for recording, while circumventing problems associated with VOG recording. The present paper describes a practical method for recording horizontal saccades using oculomotor paradigms with high accuracy and stability by EOG in neurological patients. The necessary measures are to use an Ag-AgCl electrode with a wide plastic fringe capable of reducing noise, and to wait for sufficient light adaptation to occur. This waiting period also helps to lower the impedance between the electrodes and the skin, thereby ensuring stable signal recorded as time goes by. Furthermore, re-calibration is performed as needed during the task performance. Using this method, the experimenter can avoid drifts of signals, as well as contamination of artifacts or noise from the electromyogram and electroencephalogram, and can collect sufficient data for clinical evaluation of saccades. Thus when implemented, EOG can still be a method of high practicability that can be widely applied to neurological patients, but may be effective also for studies in normal subjects.

The article describes a practical method for recording horizontal eye movements with high accuracy by electro-oculogram in neurological patients, using a cup Ag-AgCl electrode with a wide plastic fringe. Stable measurement requires proper selection and fixation of electrodes, taking sufficient time for light adaptation to occur, and re-calibration as needed.

Electro-oculogram (EOG) has been widely used for clinical eye movement recording, especially horizontal saccades, although the video-oculography (VOG) has ...

Eye Tracking During Visually Situated Language Comprehension: Flexibility and Limitations in Uncovering Visual Context Effects

The present work is a description and an assessment of a methodology designed to quantify different aspects of the interaction between language processing and the perception of the visual world. The recording of eye-gaze patterns has provided good evidence for the contribution of both the visual context and linguistic/world knowledge to language comprehension. Initial research assessed object-context effects to test&#160;theories of modularity in language processing. In the introduction, we describe how subsequent investigations have taken the role of the wider visual context in language processing as a research topic in its own right, asking questions such as how our visual perception of events and of speakers contributes to&#160;comprehension informed by&#160;comprehenders&#39; experience. Among the examined aspects of the visual context are actions, events, a speaker&#39;s gaze, and emotional facial expressions, as well as spatial object configurations. Following an overview of the eye-tracking method and its different applications, we list the key steps of the methodology in the protocol, illustrating how to successfully use it to study visually-situated language comprehension. A final section presents three sets of representative results and illustrates the benefits and limitations of eye tracking for investigating the interplay between the perception of the visual world and language comprehension.

The present article reviews an eye-tracking methodology for studies on language comprehension. To obtain reliable data, key steps of the protocol must be followed. Among these are the correct set-up of the eye tracker (e.g., ensuring good quality of the eye and head images) and accurate calibration.

The present work is a description and an assessment of a methodology designed to quantify different aspects of the interaction between language processing ...

Eye-tracking to Distinguish Comprehension-based and Oculomotor-based Regressive Eye Movements During Reading

Regressive eye movements are eye movements that move backwards through the text and comprise approximately 10-25% of eye movements during reading. As such, understanding the causes and mechanisms of regressions plays an important role in understanding eye movement behavior. Inhibition of return (IOR) is an oculomotor effect that results in increased latency to return attention to a previously attended target versus a target that was not previously attended. Thus, IOR may affect regressions. This paper describes how to design materials to distinguish between regressions caused by comprehension-related and oculomotor processes; the latter is subject to IOR. The method allows researchers to identify IOR and control the causes of regressions. While the method requires tightly controlled materials and large numbers of participants and materials, it allows researchers to distinguish and control the types of regressions that occur in their reading studies.

The method was designed to investigate the role of inhibition of return (IOR) in regressive eye movements during reading. The focus is on differentiating between regressions triggered as a result of comprehension difficulty versus those triggered from oculomotor error, including the role of IOR in the two types of regressions.

Regressive eye movements are eye movements that move backwards through the text and comprise approximately 10-25% of eye movements during reading. As ...

Using the Visual World Paradigm to Study Sentence Comprehension in Mandarin-Speaking Children with Autism

Sentence comprehension relies on the ability to rapidly integrate different types of linguistic and non-linguistic information. However, there is currently a paucity of research exploring how preschool children with autism understand sentences using different types of cues. The mechanisms underlying sentence comprehension remains largely unclear. The present study presents a protocol to examine the sentence comprehension abilities of preschool children with autism. More specifically, a visual world paradigm of eye-tracking is used to explore the moment-to-moment sentence comprehension in the children. The paradigm has multiple advantages. First, it is sensitive to the time course of sentence comprehension and thus can provide rich information about how sentence comprehension unfolds over time. Second, it requires minimal task and communication demands, so it is ideal for testing children with autism. To further minimize the computational burden of children, the present study measures eye movements that arise as automatic responses to linguistic input rather than measuring eye movements that accompany conscious responses to spoken instructions.

We present a protocol to examine the use of morphological cues during real-time sentence comprehension by children with autism.

Sentence comprehension relies on the ability to rapidly integrate different types of linguistic and non-linguistic information. However, there is ...

Loneliness Assuaged: Eye-Tracking an Audience Watching Barrage Videos

Researchers usually theorize media exposure based on assumptions of legacy media. However, a new interactive video viewing format, in this case barrage video where viewers&#8217; comments are overlaid over visual content, challenges past perspectives. This study proposes an activation and match satisfaction model to study viewing behaviors of lonely people and to challenge previous claims. It presents a protocol to examine the mechanism of how loners use barrage videos by combining eye tracking and self-report measures. Eye tracking documents the audience&#39;s conscious and subconscious watching behaviors in real time and allows for inference of the amount of allocated cognitive resources in response to rational and emotional content. The self-report gauges the amount of satisfaction obtained. Overall, results from the measures supported an activation and match satisfaction model regarding loners and their barrage video viewing behaviors. Implications are discussed.

The study proposes an activation-match model to study how loneliness is mitigated when a lonely audience watches barrage videos of rational and emotional appeals. The protocol uses eye tracking to document duration and fixation, accounting for the degree of satisfaction when emotional needs are appeased by content and barrage.

Researchers usually theorize media exposure based on assumptions of legacy media. However, a new interactive video viewing format, in this case barrage ...

Investigating Oculomotor Responses in Visual Duration Perception Tasks

Eye Movements in Visual Duration Perception: Disentangling Stimulus from Time in Predecisional Processes

Eye-tracking methods may allow the online monitoring of cognitive processing during visual duration perception tasks, where participants are asked to estimate, discriminate, or compare time intervals defined by visual events like flashing circles. However, and to our knowledge, attempts to validate this possibility have remained inconclusive so far, and results remain focused on offline behavioral decisions made after stimulus appearance. This paper presents an eye-tracking protocol for exploring the cognitive processes preceding behavioral responses in an interval comparison task, where participants viewed two consecutive intervals and had to decide whether it speeded up (first interval longer than second) or slowed down (second interval longer). 
Our main concern was disentangling oculomotor responses to the visual stimulus itself from correlates of duration related to judgments. To achieve this, we defined three consecutive time windows based on critical events: baseline onset, the onset of the first interval, the onset of the second interval, and the end of the stimulus. We then extracted traditional oculomotor measures for each (number of fixations, pupil size) and focused on time-window-related changes to separate the responses to the visual stimulus from those related to interval comparison per se. As we show in the illustrative results, eye-tracking data showed significant differences that were consistent with behavioral results, raising hypotheses on the mechanisms engaged. This protocol is embryonic and will require many improvements, but it represents an important step forward in the current state of art.

Author Spotlight: Exploring the Link Between Time Perception of Visual Stimuli and Reading Skills

We present a protocol that employs eye tracking to monitor eye movements during an interval comparison (duration perception) task based on visual events. The aim is to provide a preliminary guide to separate oculomotor responses to duration perception tasks (comparison or discrimination of time intervals) from responses to the stimulus itself.

Eye-tracking methods may allow the online monitoring of cognitive processing during visual duration perception tasks, where participants are asked to ...

Eye Tracking in Cognitive Experiments

Eye tracking as the name suggests involves tracking of eye-movements. It is a non-invasive, sensitive tool that quantifies and measures eye-movements to describe an individuals' cognitive state. An eye-movement between two fixation points is called a saccade, which is one of the fastest motor movements in our body. By observing the profiles of these eye movements, scientists can better understand neural deficits in patients with cognitive impairments.
In this video, we will first look at an overview of different eye movements that eye tracking can capture and the type of data that can be collected. Then, the basic setup and experimental design are reviewed, including different types of eye trackers and details to optimize the eye tracking equipment. Finally, we will take a look at a few specific experiments utilizing eye tracking as a tool to study cognition.

Eye Tracking in Cognitive Experiments: Principle and Procedure

Eye tracking as the name suggests involves tracking of eye-movements. It is a non-invasive, sensitive tool that quantifies and measures eye-movements to ...