Project 2: Levari Exp.20: 2D - Partial Feedback NOTE: Note, This is One of Many Studies Under Project 2 in the Original Grant
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 55
- 试验地点
- 1
- 主要终点
- Percentage of stimuli identified as target items
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- Single (Participant)
盲法说明
Observers are naive as to the purpose of the experiment until after participation
入排标准
- 年龄范围
- 18 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •normal color vision- 20/25 or better acuity
排除标准
- •no history of visual or oculomotor disease-
研究组 & 干预措施
Color Feedback
Observers are told if the color but not if the shape was correctly identified
干预措施: Color Feedback (Behavioral)
Shape Feedback
Observers are told if the shape but not if the color was correctly identified
干预措施: Shape Feedback (Behavioral)
结局指标
主要结局
Percentage of stimuli identified as target items
时间窗: 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.
次要结局
未报告次要终点
研究者
Jeremy M Wolfe, PhD
Professor
Brigham and Women's Hospital