A LOT of my research relies on eye tracking tech. I thought I'd write a post about it.

https://news.emory.edu/stories/2013/11/signs_of_autism_in_first_months_of_life/campus.html

Long before they can crawl or even pick up a toy, babies use their eyes to explore the world around them.

I study how babies learn about other people, and how they learn to interact with others. And since I can’t ask them questions about their thoughts of feelings, or have them participate in laboratory tasks…I use eye-tracking technology to figure out what’s going on inside their tiny heads!

How it works

Think of the eye-tracker as a very high-speed camera. It sends out near-infrared light towards the infant, which then reflects off the pupil and cornea. These reflections are tracked by the camera so that we know where the baby is looking.

The eye-tracker that I use collects 300 samples a second. That means that we get a read-out of where baby is looking every 3.3ms. For some questions – like, “do babies like to look at colorful things?” – this sampling is overkill. For others, – like, “what does the structure in the noise of eye movements tell us about attention” – this high-density sampling is critical.

https://news.cision.com/tobii-ab/i/eye-tracking-study-small-child-tobii-pro-fusion,c2699383

What kinds of questions can we ask?

It's all about connecting those eye movements to what the baby is looking at.

Here is a snapshot from a movie we show babies (they love this movie, which features three ladies dancing around with baloons). The pink blobs represent where the baby is looking.

We can start to ask questions like: Do babies spend more time looking at the ladies’ faces than the background?

How does movement impact where they direct their attention to?

Does their attention to social information predict their social/cognitive outcomes?

We can take summary statistics of their eye movements, and calculate the proportion of time they look at faces relative to other objects on the screen.

We can do time series analyses as well, and look at moment-by-moment changes in their eye-gaze.

What else can eye tracking be used for?

You may have heard the phrase “the eyes are the windows to the soul.” They're certainly a window to human cognition! Eye movements give us information about what catches our attention, how we explore our environments, and what information we use to guide decision making.

Eye tracking is also being used in PC gaming, and as assistive technology to help with everyday computer use. s