Welcome to the Lookit experiment runner’s documentation!

Building a study on Lookit and using Lookit’s own experiment runner? You’re in the right place to learn how to put together the study protocol you have in mind. To the left you can find information about…

Specifying your study protocol

The basics of how to structure either a JSON document or a Javascript function that describes your study protocol.

Features common to all frames

There are some features that are common to all frames, like being able to set a generateProperties function to adjust parameters on-the-fly based on what the child has done so far.

Specific frames

These are you can use in your Lookit study, like instructions pages or looking-time trials. The documentation will tell you how each frame works, what data it collects, and what parameters you need to give it.


Some frames use “mixins” that provide some shared functionality. For instance, a few frames use the “infant-controlled-timing” mixin that allows you to specify a button for the parent to press to indicate the child isn’t looking, and move on after a specified lookaway time. Each frame will say what mixins it uses, but to keep things concise, you’ll find information about what parameters to include and what data will be collected here.


Generally, you’ll want to show slightly different versions of the study to different participants: perhaps you have a few different conditions, and/or need to counterbalance the order of trials or left/right position of stimuli. You have several options for how to handle this, depending on your preferences and the complexity of your design.