Ignite Creation Date:
2024-05-06 @ 8:22 PM
Last Modification Date:
2024-10-26 @ 3:26 PM
Study NCT ID:
NCT06355999
Status:
COMPLETED
Last Update Posted:
2024-04-10
First Post:
2024-03-27
Brief Title:
Levari Exp20 2D - Partial Feedback
Sponsor:
Brigham and Womens Hospital
Organization:
Brigham and Womens Hospital
Study Overview
Official Title:
Project 2 Levari Exp20 2D - Partial Feedback NOTE Note This is One of Many Studies Under Project 2 in the Original Grant
Status:
COMPLETED
Status Verified Date:
2024-08
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief 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 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 eg 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 08 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 06 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 005 and power of 09 The investigators will aim for 26 observers in each condition
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 eg 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 08 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 06 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 005 and power of 09 The investigators will aim for 26 observers in each condition
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None