Health TrialsbyHealthPanel

An Investigation of Attentional and Inhibitory Processes During Active Visual Search in Humans

ConditionsEye MovementsAttentionExecutive Function
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-65
SponsorUniversity of Colorado, Denver

About this trial

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.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

18-65 years old

Disqualifiers

Self-reported history of neurological illness

Uncorrected vision problems

Trial design

Design model

Parallel

Treatments tested in this trial

  • Contour Search Task

    Other intervention

    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.

  • Stop signal Task

    Behavioral

    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.

  • Useful field of View

    Behavioral

    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.

  • Attentional capture search task

    Behavioral

    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.

Treatment groups

225 Participants
are divided into 2 treatment groups
Group A: Study Group Contour SearchExperimental treatment 3 interventions
Group B: Study Group Attentional CaptureExperimental treatment 3 interventions

Trial outcomes

Primary outcomes

1

First fixation duration during visual search

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.

Time frame
During visual search task
2

Fixation count during visual search

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.

Time frame
During visual search task
3

Stop signal reaction time

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.

Time frame
During inhibitory task
4

Useful field of view thresholding

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.

Time frame
During attention task

Secondary outcomes

1

Average fixation duration during visual search

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.

Time frame
During the visual search task

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Colorado, Denver

Lead sponsor

National Eye Institute (NEI)

Collaborator

Source ClinicalTrials.gov
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