Eye Movements, Attention, Executive Function
Conditions
Keywords
Individual differences, Eye movements, Perception, Attention, Inhibition
Brief summary
The goal of this study is to investigate the finding that there are large individual differences in how participants move their eyes during active visual search. For example, some individuals tend to fixate, that is point their eyes steadily at a single location, for longer than other individuals before moving to another location. This experiment will use behavioral tasks to measure an individual's attentional and inhibitory functioning, and then see how each of these contributes to between-participant variability in eye movement behavior during visual search.
Detailed description
To accomplish the goal of understanding the source of individual variability in eye movement patterns, each participant will complete three separate tasks. The first task will require participants to find a target and eye movements will be measured to assess individual differences in fixation duration and other types of eye movement behavior. A second task will evaluate attentional functioning over the visual field by requiring participants to detect briefly-presented targets using their peripheral vision. Finally, a third task will assess inhibitory functioning by having participants attempt to stop eye movements after they have been programmed.
Interventions
OTHERContour Search Task
In this task, participants sit in front of a computer screen with their head in a chinrest to control for distance from the monitor and eye-tracking equipment. For the visual search task, participants will search for a visual target among distractors and make a response regarding its orientation. The target is defined by a contour formed through oriented Gabor patches.
BEHAVIORALStop signal Task
In this task, participants sit in front of a computer screen with their head in a chinrest to control for distance from the monitor and eye-tracking equipment. For the stop-signal task, participants will make an eye movement to a target that appears on the screen, except on trials where a visual signal appears indicating they should cancel this behavior.
BEHAVIORALUseful field of View
In this task, participants sit in front of a computer screen with their head in a chinrest to control for distance from the monitor and eye-tracking equipment. In the useful field of view task, participants will report the location of a briefly-presented and masked target, while also responding to the identify of a central target in some blocks.
BEHAVIORALAttentional capture search task
In this task, participants sit in front of a computer screen with their head in a chinrest to control for distance from the monitor and eye-tracking equipment. For this visual search task, participants will search for a visual target among distractors and make a response regarding its orientation. The target is defined as a unique shape, and is sometimes shown with a salient distractor.
Sponsors
University of Colorado, Denver
National Eye Institute (NEI)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention model description
Basic Experimental Studies Involving Humans (BESH)
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* 18-65 years old
Exclusion criteria
* Self-reported history of neurological illness * Uncorrected vision problems
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| First fixation duration during visual search | During visual search task | This measure is the average first fixation duration during the visual search task. Possible scores are a minimum of 50 ms with an undeterminable positive number of ms as a maximum. This measure indicates the duration of processing before the first eye movement decision. |
| Fixation count during visual search | During visual search task | This measure is the count the average number of eye movements participants made per trial during the visual search task. Possible scores range from a minimum of 0 to approximately 40 eye movements, given the time available. This measure indicates the amount of active exploration of the display during search. |
| Stop signal reaction time | During inhibitory task | Stop signal reaction time is a quantitative estimate of how long participants take to successfully inhibit a planned eye movement. Possible scores range from a minimum of 0 ms to a maximum of about 600 ms. Low scores indicate strong inhibitory ability and high scores indicate weak inhibitory ability. |
| Useful field of view thresholding | During attention task | Performance in a thresholding task indicates participants ability to detect a briefly presented target among distractors with 80% accuracy. Contrast of the displays varies until performance meets achieved level. Possible scores range from 0 to 100% contrast. Lower contrast indicates better information accrual, while higher contrast indicates worse. |
| Useful field of view dual task performance | During attention task | Performance in a dual task indicates participants ability to spread attention across the visual field. Possible scores range from 0 to 100% accuracy. Higher performance indicates better information accrual, while lower performance indicates worse. |
| Oculomotor capture by salient distractor | During visual search task | in the attentional capture search task, a measure of how often participants look at the salient yet irrelevant distractor will be calculated. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Average fixation duration during visual search | During the visual search task | This measure is the average fixation duration across all fixations in a trial during the visual search task. Possible scores range from a minimum of 50 ms to approximately 500 ms. This measure indicates the average duration of processing before a saccadic decision is made. |
Countries
United States
Contacts
CONTACTCarly J Principal Investigator, PhD
CONTACTRyan V Postdoctoral Fellow, PhD
PRINCIPAL_INVESTIGATORCarly J Leonard, Phd
University of Colorado enver
Outcome results
None listed