exp-lookit-stimuli-preview

Overview

A frame that to explain any blinding procedures to parents, and offer them the option to preview stimuli before the study. Two buttons are available to move on: one turns on video recording & shows the stimuli previews (if the parent wants to preview stimuli), and one moves on to the next frame that (if the parent declines).

What it looks like

Example screenshot from exp-lookit-stimuli-preview frame

Recording

If doRecording is true, then the family is recorded while previewing stimuli if they choose to. This is so that if you want to make sure the child didn’t see stimuli ahead of the study you can check.

Specifying where files are

Several of the parameters for this frame can be specified either by providing a list of full URLs and file types, or by providing just a filename that will be interpreted relative to the baseDir. See the expand-assets mixin tool that this frame uses.

More general functionality

Below is information specific to this particular frame. There may also be available parameters, events recorded, and data collected that come from the following more general sources:

Example

"my-video-preview": {
    "kind": "exp-lookit-stimuli-preview",
    "doRecording": true,
    "skipButtonText": "Skip preview",
    "requirePreview": false,
    "previewButtonText": "I'd like to preview the videos",
    "blocks": [
        {
             "text": "During the videos, we'll ask that you hold your child over your shoulder like this, so that you're facing face away from the screen."
        },
        {
            "image": {
                "alt": "Father holding child looking over his shoulder",
                "src": "https://raw.githubusercontent.com/kimberscott/placeholder-stimuli/master/img/OverShoulder.jpg"
            }
        },
        {
            "text": "This is because your child is learning from you all the time, and may pick up on even very small cues about what you think. But if you can't see the stimuli, we're definitely only measuring your child's own beliefs."
        },
        {
            "text": "If you'd like to see the videos your child will be shown, you can take a look ahead of time now. It's important that you preview the videos without your child, so that the videos will still be new to them."
        }
    ],
    "showPreviousButton": true,
    "baseDir": "https://raw.githubusercontent.com/kimberscott/placeholder-stimuli/master/",
    "videoTypes": ["webm", "mp4"],
    "audioTypes": ["mp3", "ogg"],
    "stimuli": [
       {
         "caption": "At the start of each section, we will play a video like this that shows a common household object, like a book or an apple.",
         "video": "cropped_book"
       },
       {
         "caption": "Your child will be looking at images like this, and we'll ask him or her to describe each one.",
         "image": "square.png"
       },
       {
         "caption": "Between sections, we will play audio like this so you know where you are in the study.",
         "audio": "sample_1"
       }
     ]
}

Parameters

showPreviousButton [Boolean | true]

Whether to show a ‘previous’ button

blocks [Array]

Array of text blocks to display as an introduction to the preview. Should be a list of objects that can be passed to exp-text-block; each can have any of the properties below.

previewButtonText [String | 'I\'d like to preview the videos'

Text on the preview button user clicks to proceed to stimuli/images

requirePreview [Boolean | false]

Whether to require previewing the stimuli. If true, no button to skip preview is provided.

skipButtonText [String | 'Skip preview']

Text to display on the button to skip the next frame

stimuli [Array]

An array of preview stimuli to display within a single frame, defined as an array of objects. Generally each item of the list will include ONE of image, video, or audio (depending on the stimulus type), plus a caption. Each item can have fields:

caption

[String] Some text to appear above this video/audio/image

video

[String or Array] String indicating video URL. This can be relative to baseDir, OR Array of {src: ‘url’, type: ‘MIMEtype’} objects.

audio

[String or Array] String indicating audio URL. This can be relative to baseDir, OR Array of {src: ‘url’, type: ‘MIMEtype’} objects.

image

[String] URL of image to display. Can be full path or relative to baseDir/img.

nextStimulusText [String | 'Next']

Text on the button to proceed to the next example video/image

previousStimulusText [String | 'Previous']

Text on the button to proceed to the previous example video/image

doRecording [Boolean | true]

Whether to make a webcam video recording during stimulus preview (begins only if user chooses to preview stimuli). Default true.

Data collected

No fields are added specifically for this frame type.

Events recorded

The events recorded specifically by this frame are:

startPreview

User clicks on start preview button

nextStimulus

User clicks to move to next stimulus

previousStimulus

User clicks to move to previous stimulus

Updating from deprecated frames

Updating from separate exp-video-preview-explanation and exp-video-preview frames

If you currently use separate exp-video-preview-explanation and exp-video-preview frames, you will need to update to a single exp-lookit-stimuli-preview frame when updating the experiment runner. Follow the steps below to update.

  1. Combine the two frames into one (pooling all the parameters), and change its kind to exp-lookit-stimuli-preview.

  2. Move the value of introBlock to be the first element of blocks, and move the image to a new additional element, like this:

    "introBlock": {
    "text": "During the videos, we'll ask that you hold your child over your shoulder like this, so that you're facing face away from the screen."
},
"image": {
    "alt": "Father holding child looking over his shoulder",
    "src": "https://s3.amazonaws.com/lookitcontents/exp-physics/OverShoulder.jpg"
},
"blocks": [
    {
        "text": "The reason we ask this is that your child is learning from you all the time. Even if he or she can't see where you're looking, you may unconsciously shift towards one side or the other and influence your child's attention. We want to make sure we're measuring your child's preferences, not yours!"
    },
    {
        "text": "If you'd like to see the videos your child will be shown, you can take a look ahead of time now. It's important that you preview the videos without your child, so that the videos will still be new to them."
    }
],
...

    would become:

    "blocks": [
    {
        "text": "During the videos, we'll ask that you hold your child over your shoulder like this, so that you're facing face away from the screen."
    },
    {
        "image": {
            "alt": "Father holding child looking over his shoulder",
            "src": "https://s3.amazonaws.com/lookitcontents/exp-physics/OverShoulder.jpg"
        }
    },
    {
        "text": "The reason we ask this is that your child is learning from you all the time. Even if he or she can't see where you're looking, you may unconsciously shift towards one side or the other and influence your child's attention. We want to make sure we're measuring your child's preferences, not yours!"
    },
    {
        "text": "If you'd like to see the videos your child will be shown, you can take a look ahead of time now. It's important that you preview the videos without your child, so that the videos will still be new to them."
    }
],
...

  3. Remove the text and prompt parameters. (If you had something important in there, move it to “blocks”.)

  4. Rename videos to stimuli. Within stimuli change any properties named sources to video, and change any properties named imgSrc to image.

Suppose you started with the following two frames:

"my-preview-explanation": {
    "introBlock": {
        "text": "During the videos, we'll ask that you hold your child over your shoulder like this, so that you're facing face away from the screen."
    },
    "image": {
        "alt": "Father holding child looking over his shoulder",
        "src": "https://s3.amazonaws.com/lookitcontents/exp-physics/OverShoulder.jpg"
    },
    "kind": "exp-lookit-preview-explanation",
    "skipButtonText": "Skip preview",
    "previewButtonText": "I'd like to preview the videos",
    "blocks": [
        {
            "text": "The reason we ask this is that your child is learning from you all the time. Even if he or she can't see where you're looking, you may unconsciously shift towards one side or the other and influence your child's attention. We want to make sure we're measuring your child's preferences, not yours!"
        },
        {
            "text": "If you'd like to see the videos your child will be shown, you can take a look ahead of time now. It's important that you preview the videos without your child, so that the videos will still be new to them."
        }
    ],
    "showPreviousButton": true
},
"my-preview-frame": {
    "id": "video-preview",
    "kind": "exp-video-preview",
    "text": "Here are the videos your child will see in this study. You can watch them ahead of time--please just don't show your child yet!",
    "prompt": "My child can NOT see the screen. Start the preview!",
    "baseDir": "https://url.com/",
    "videoTypes": ["webm", "mp4"],
    "videos": [
       {
         "caption": "User-facing text that appears below the video",
         "sources": "example_intro"
       },
       {
         "caption": "User-facing text that appears below the video",
         "imgSrc": "caterpillar_picture"
       }
     ]
}

Following the steps above, you would end up with:

"my-preview-explanation": {
    "kind": "exp-lookit-stimuli-preview",

    "skipButtonText": "Skip preview",
    "previewButtonText": "I'd like to preview the videos",
    "blocks": [
        {
             "text": "During the videos, we'll ask that you hold your child over your shoulder like this, so that you're facing face away from the screen."
        },
        {
            "image": {
                "alt": "Father holding child looking over his shoulder",
                "src": "https://raw.githubusercontent.com/kimberscott/placeholder-stimuli/master/img/OverShoulder.jpg"
            }
        },
        {
            "text": "This is because your child is learning from you all the time, and may pick up on even very small cues about what you think. But if you can't see the stimuli, we're definitely only measuring your child's own beliefs."
        },
        {
            "text": "If you'd like to see the videos your child will be shown, you can take a look ahead of time now. It's important that you preview the videos without your child, so that the videos will still be new to them."
        }
    ],
    "showPreviousButton": true,
    "baseDir": "https://url.com/",
    "videoTypes": ["webm", "mp4"],
    "stimuli": [
       {
         "caption": "User-facing text that appears below the video",
         "video": "example_intro"
       },
       {
         "caption": "User-facing text that appears below the video",
         "image": "caterpillar_picture"
       }
     ]
}