Form PerceptionNCT06355999
Levari Exp.20: 2D - Partial Feedback
A study testing Color Feedback and Shape Feedback in people with Form Perception and Color Perception, run by Brigham and Women's Hospital at 1 site in United States.
Trial summary
Suppose that observers are trying to classify a spot on the skin as normal or abnormal and suppose that the two attributes that are important are the color and shape of the spot. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Form Perception, Color Perception, Decision Making
- What is being tested?
- Color Feedback and Shape Feedback
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 55 participants
- Where
- 1 siteUnited States
- Study dates
- 1 May 2021to 1 Jun 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- normal color vision- 20/25 or better acuity
Who cannot join
- no history of visual or oculomotor disease-
Trial locations and contacts
1 site in 1 country.
United States1 site
Visual Attention Lab / Brigham and Women's Hospital
Boston, Massachusetts, 02215
About this study
Official title: Project 2: Levari Exp.20: 2D - Partial Feedback NOTE: Note, This is One of Many Studies Under Project 2 in the Original Grant
Suppose that observers are trying to classify a spot on the skin as normal or abnormal and suppose that the two attributes that are important are the color and shape of the spot. The investigators have found that perceptual decisions of this short are shaped by the prevalence of the target abnormality and by the feedback that observers (Os) receive. If abnormal spots are rare (low prevalence), Os will tend to become more conservative about calling spots abnormal. In this experiment, Os see items defined by color and shape. They are looking for one combination (bumpy green). Bumpy green targets can be common (50% prevalence) or rare (10%). Os in one group will get feedback about their responses based on color. The other group will receive feedback based on shape. The investigators will look for effects of prevalence and of the type of feedback. The goal is to better understand perceptual decisions in settings like clinical evaluation of skin lesions.
Read the detailed description
Suppose that observers are trying to classify a spot on the skin as normal or abnormal and suppose that the two attributes that are important are the color and shape of the spot. The investigators have found that perceptual decisions of this short are shaped by the prevalence of the target abnormality and by the feedback that observers (Os) receive. If abnormal spots are rare (low prevalence), Os will tend to become more conservative about calling spots abnormal.
In this experiment, Os see items defined by color and shape. Items vary in dominant color from purple to green. Items vary in shape from relatively smooth irregular blobs (nicknamed "Bouba") to relatively bumpy blobs (nicknamed "Kiki"). Os are asked to find "Green Kikis". Since color and shape vary continuously, the border between Green Kiki and not Green Kiki will not be clear to the Os. Os will be asked to label each item as Green Kiki or not. Saying "maybe" is not an option.
The between-subject variable is the type of feedback Os receive. One set of Os will get feedback about color. That is, if the observer says "yes, this is a green kiki", they will be told only "Yes, this was a green item" or "no this was not green". The other group will get shape feedback: e.g. "Yes, this was a Kiki.".
The within-subjects variable is the target prevalence. The investigators can divide the stimuli into four quadrants: Green Kiki targets, and Green Bouba, Purple Bouba, and Purple Kiki distractors. In the high prevalence trials, 50% of the stimuli will be drawn from target quadrant (green kiki) and 17% from each of the remaining three quadrants. In the low prevalence trials, 10% of the stimuli will be drawn from the target quadrant while 30% will be drawn from each of the other three quadrants. The whole space of stimuli has 10 shape values and 10 color values for a total of 100 possible types of stimulus.
The key dependent is the proportion of target-present responses for each type of stimulus.
To analyze the data, the investigators will create a heatmap showing the percentage of times Os judge each of the 100 categories (10 colors X 10 shapes) as the target, separately for the high prevalence and low prevalence block. The investigators will calculate the response difference between the two blocks within subjects and will calculate the difference between shape and color feedback between observers.
Observers with an average accuracy below 70% will be excluded. Prior experiments have a conservative effect size of ~0.8 for differences between high and low prevalence. Some effects in experiments proposed here may have more subtle effects so power will be calculated based on an effect size of 0.6. To detect such a difference between, for instance, the 50% points on two functions like those in the data figures above, requires 26 observers to achieve alpha of 0.05 and power of 0.9. The investigators will aim for 26 observers in each condition.
- Conditions
- Form Perception, Color Perception, Decision Making
- Being tested
- Color Feedback, Shape Feedback
- Keywords
- shape perception, decision making, prevalence effects, feedback
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Color FeedbackBehavioural
Feedback is given about the correctness of the response on the color dimension
Shape FeedbackBehavioural
Feedback is given about the correctness of the response on the shape dimension
| Study group | Role | What they receive |
|---|---|---|
| Color Feedback | Experimental | Observers are told if the color but not if the shape was correctly identified Receives: Behavioral: Color Feedback |
| Shape Feedback | Experimental | Observers are told if the shape but not if the color was correctly identified Receives: Behavioral: Shape Feedback |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of stimuli identified as target items
Participants are presented with visual stimuli from a 10 by 10 set of 100 possibilities. There are 10 levels of color (blue to green) and 10 levels of shape (smooth="Bouba" to bumpy = "Kiki", fully crossed with each other. Participants are asked to state whether an item is or is not a "green Kiki" target. For each of the 100 items, the primary outcome measure is the percentage of time that the specific item is called "Green Kiki" target.
Measured: Through study completion, an average one 1 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Apr 2024
- Study start1 May 2021
- Primary completion1 Jun 2021
- Study completion1 Jun 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Form PerceptionStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Two groups, each receiving different feedback
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 55 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Jeremy M Wolfe, PhD, Brigham and Women's Hospital
- Investigators
- Jeremy M Wolfe, PhD, Principal investigator, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06355999
- Sponsor's protocol ID
- 2007p000646-F
- Status last verified
- Aug 2024
- First submitted
- 27 Mar 2024
- Last updated
- 13 Aug 2024
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: de-identified data will be posted on the Open Science Framework site
Study at a glance
From the registry record, last updated by the sponsor on 13 Aug 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Project 2: Levari Exp.20: 2D - Partial Feedback NOTE: Note, This is One of Many Studies Under Project 2 in the Original Grant
- ClinicalTrials.gov ID
- NCT06355999
- Acronym / sponsor ID
- 2007p000646-F
- Conditions
- Form Perception, Color Perception, Decision Making
- Keywords
- shape perception, decision making, prevalence effects, feedback
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 55 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Study start
- 1 May 2021 (actual)
- Primary completion
- 1 Jun 2021 (actual)
- Study completion
- 1 Jun 2021 (actual)
- First posted
- 10 Apr 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Suppose that observers are trying to classify a spot on the skin as normal or abnormal and suppose that the two attributes that are important are the color and shape of the spot. The investigators have found that perceptual decisions of this short are shaped by the prevalence of the target abnormality and by the feedback that observers (Os) receive. If abnormal spots are rare (low prevalence), Os will tend to become more conservative about calling spots abnormal. In this experiment, Os see items defined by color and shape. They are looking for one combination (bumpy green). Bumpy green targets can be common (50% prevalence) or rare (10%). Os in one group will get feedback about their responses based on color. The other group will receive feedback based on shape. The investigators will look for effects of prevalence and of the type of feedback. The goal is to better understand perceptual decisions in settings like clinical evaluation of skin lesions.
Detailed description
Suppose that observers are trying to classify a spot on the skin as normal or abnormal and suppose that the two attributes that are important are the color and shape of the spot. The investigators have found that perceptual decisions of this short are shaped by the prevalence of the target abnormality and by the feedback that observers (Os) receive. If abnormal spots are rare (low prevalence), Os will tend to become more conservative about calling spots abnormal.
In this experiment, Os see items defined by color and shape. Items vary in dominant color from purple to green. Items vary in shape from relatively smooth irregular blobs (nicknamed "Bouba") to relatively bumpy blobs (nicknamed "Kiki"). Os are asked to find "Green Kikis". Since color and shape vary continuously, the border between Green Kiki and not Green Kiki will not be clear to the Os. Os will be asked to label each item as Green Kiki or not. Saying "maybe" is not an option.
The between-subject variable is the type of feedback Os receive. One set of Os will get feedback about color. That is, if the observer says "yes, this is a green kiki", they will be told only "Yes, this was a green item" or "no this was not green". The other group will get shape feedback: e.g. "Yes, this was a Kiki.".
The within-subjects variable is the target prevalence. The investigators can divide the stimuli into four quadrants: Green Kiki targets, and Green Bouba, Purple Bouba, and Purple Kiki distractors. In the high prevalence trials, 50% of the stimuli will be drawn from target quadrant (green kiki) and 17% from each of the remaining three quadrants. In the low prevalence trials, 10% of the stimuli will be drawn from the target quadrant while 30% will be drawn from each of the other three quadrants. The whole space of stimuli has 10 shape values and 10 color values for a total of 100 possible types of stimulus.
The key dependent is the proportion of target-present responses for each type of stimulus.
To analyze the data, the investigators will create a heatmap showing the percentage of times Os judge each of the 100 categories (10 colors X 10 shapes) as the target, separately for the high prevalence and low prevalence block. The investigators will calculate the response difference between the two blocks within subjects and will calculate the difference between shape and color feedback between observers.
Observers with an average accuracy below 70% will be excluded. Prior experiments have a conservative effect size of ~0.8 for differences between high and low prevalence. Some effects in experiments proposed here may have more subtle effects so power will be calculated based on an effect size of 0.6. To detect such a difference between, for instance, the 50% points on two functions like those in the data figures above, requires 26 observers to achieve alpha of 0.05 and power of 0.9. The investigators will aim for 26 observers in each condition.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- Two groups, each receiving different feedback
| Arm | Type | Receives |
|---|---|---|
| Color Feedback | Experimental | Behavioral: Color FeedbackObservers are told if the color but not if the shape was correctly identified |
| Shape Feedback | Experimental | Behavioral: Shape FeedbackObservers are told if the shape but not if the color was correctly identified |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- normal color vision- 20/25 or better acuity
Key exclusion criteria (1 listed)
- no history of visual or oculomotor disease-
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Color FeedbackFeedback is given about the correctness of the response on the color dimension | Behavioural | Color Feedback |
| Shape FeedbackFeedback is given about the correctness of the response on the shape dimension | Behavioural | Shape Feedback |
Primary outcome
Percentage of stimuli identified as target items
Time frame: Through study completion, an average one 1 year
Participants are presented with visual stimuli from a 10 by 10 set of 100 possibilities. There are 10 levels of color (blue to green) and 10 levels of shape (smooth="Bouba" to bumpy = "Kiki", fully crossed with each other. Participants are asked to state whether an item is or is not a "green Kiki" target. For each of the 100 items, the primary outcome measure is the percentage of time that the specific item is called "Green Kiki" target.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 13 Aug 2024.
- Individual participant dataSharing planned: Yes. de-identified data will be posted on the Open Science Framework site
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jeremy M Wolfe, PhD principal investigator
Brigham and Women's Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Color Feedback and Shape Feedback in people with Form Perception and Color Perception, run by Brigham and Women's Hospital at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 13 Aug 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of stimuli identified as target items (time frame: Through study completion, an average one 1 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 13 Aug 2024; AzTrials last refreshed its copy on 31 Oct 2026.