A new study by MIT researchers directly shows that
visual attention can reveal unconscious, tacit knowledge during image
classification tasks. Credit: MIT News
Expertise isn't easy to pass down. Take riding a bike: A seasoned cyclist
might talk a beginner through the basics of how to sit and when to push off.
But other skills, like how hard to pedal to keep balanced, are more intuitive
and harder to articulate. This implicit know-how is known as tacit knowledge,
and very often, it can only be learned with experience and time.
But a team of MIT engineers wondered: Could an expert's unconscious
know-how be accessed, and even taught, to quickly bring a novice up to an
expert's level?
The answer appears to be "yes," at least for a particular type of
visual-learning task.
In a study published today in the Journal of Neural
Engineering, the engineers identified tacit knowledge in volunteers who
were tasked with classifying images of various shapes and patterns. As the
volunteers were shown images to organize, the team recorded their eye movements and
brain activity to measure their visual focus and cognitive attention,
respectively.
The measurements showed that, over time, the volunteers shifted their focus
and attention to a part of each image that made it easier to classify. However,
when asked directly, the volunteers were not aware that they had made such a
shift. The researchers concluded that this unconscious shift in attention and
focus was a form of tacit knowledge that the volunteers possessed, even if they
could not articulate it. What's more, when the volunteers were made aware of
this tacit knowledge, their accuracy in classifying images improved
significantly.
The study is the first to directly show that visual attention can reveal
unconscious, tacit knowledge during image classification tasks. It also finds
for the first time that bringing this concealed knowledge to the surface can
enhance experts' performance.
While the results are specific to the study's experiment, the researchers
say they suggest that some forms of hidden know-how can be made explicit and
applied to boost one's learning experience. They suspect that tacit knowledge
could be accessed for disciplines that require keen observation skills,
including certain physical trades and crafts, sports, and image analysis, such
as medical X-ray diagnoses.
"We as humans have a lot of knowledge, some that is explicit that we
can translate into books, encyclopedias, manuals, equations. The tacit
knowledge is what we cannot verbalize, that's hidden in our unconscious,"
says study author Alex Armengol-Urpi, a research scientist in MIT's Department
of Mechanical Engineering. "If we can make that knowledge explicit, we can
then allow for it to be transferred easier, which can help in education and
learning in general."
The study's co-authors include Andrés F. Salazar-Gomez, research scientist
at the MIT Media Lab; Pawan Sinha, professor of vision and computational
neuroscience in MIT's Department of Brain and Cognitive Sciences; and Sanjay
Sarma, the Fred Fort Flowers (1941) and Daniel Fort Flowers (1941) Professor in
Mechanical Engineering.
Hidden gaze
The concept of tacit knowledge is credited to the scientist and philosopher
Michael Polyani, who in the mid 20th century was the first to investigate the
notion that "we know more than we can tell." His insights revealed
that humans can hold a form of knowledge that is internalized, almost second
nature, and often difficult to express or translate to others.
Since Polyani's work, many studies have highlighted how tacit knowledge may
play a part in perfecting certain skills, spanning everything from diagnosing
medical images to discerning the sex of cats from images of their faces.
For Armengol-Urpi, these studies raised a question: Could a person's tacit
knowledge be revealed through unconscious signals, such as patterns in their
eye movements? His Ph.D. work focused on visual attention, and he had developed
methods to study how humans focus their attention, by using cameras to follow
the direction of their gaze, and electroencephalography (EEG) monitors to
record their brain activity. In his research, he learned of a previous study
that used similar methods to investigate how radiologists diagnose nodules in X-ray
images. That study showed that the doctors unconsciously focused on areas of an
image that helped them to correctly detect the nodules.
"That paper didn't focus on tacit knowledge, but it suggested that
there are some hidden clues in our gaze that could be explored further,"
Armengol-Urpi says.
The shape of knowledge
For their new study, the team looked at whether they could identify signs
of tacit knowledge from measurements of visual focus and attention. In their
experiment, they asked 30 volunteers to look sequentially at over 120 images.
They could look at each image for several seconds and then were asked to
classify the image as belonging to either group A, or group B, before they were
shown the next image.
Each image contained two simple shapes on either side of the image—a
square, a triangle, a circle, and any combination of the three, along with
different colors and patterns for each shape. The researchers designed the
images such that they should be classified into one of two groups, based on an
intricate combination of shape, color, and pattern. Importantly, only one side
of each image was relevant for the classification.
The volunteers, however, were given no guidelines on how to classify the
images. Therefore, for about the first half of the experiment, they were
considered "novices," and more or less guessed at their
classifications. Over time, and many more images, their accuracy improved to a
level that the researchers considered "expert." Throughout the
experiment, the team used cameras to follow each participant's eye movements,
as a measure of visual focus.
They also outfitted volunteers with EEG sensors to record their brain
waves, which they used as a measure of cognitive attention. They designed each
image to show two shapes, each of which flickered at different, imperceptible
frequencies. They found they could identify where a volunteer's attention
landed, based on which shape's flicker their brain waves synced up with.
For each volunteer, the team created maps of where their gaze and attention
were focused, both during their novice and expert phases. Overall, these maps
showed that in the beginning, the volunteers focused on all parts of an image
as they tried to make sense of how to classify it. Toward the end, as they got
a grasp of the exercise and improved their accuracy, their attention shifted to
just one side of each image. This side happened to be the side that the
researchers designed to be most relevant, while the other side was just random
noise.
The maps showed that the volunteers picked up some knowledge of how to
accurately classify the images. But when they were given a survey and asked to
articulate how they learned the task, they always maintained that they focused
on each entire image. It seemed their actual shift in focus was an unconscious,
tacit skill.
"They were unconsciously focusing their attention on the part of the
image that was actually informative," Armengol-Urpi says. "So the
tacit knowledge they had was hidden inside them."
Going a step further, the team then showed each participant the maps of
their gaze and attention, and how the maps changed from their novice to expert
phases. When they were then shown additional images, the volunteers seemed to
use this once-tacit knowledge, and further improved their classification
accuracy.
"We are currently extending this approach to other domains where tacit
knowledge plays a central role," says Armengol-Urpi, who is exploring
tacit knowledge in skilled crafts and sports such as glassblowing and table
tennis, as well as in diagnosing medical imaging. "We believe the
underlying principle—capturing and reinforcing implicit expertise through
physiological signals—can be generalize to a wide range of perceptual and
skill-based domains."
by Jennifer Chu, Massachusetts Institute of Technology
edited by Gaby
Clark, reviewed by Robert Egan
Provided
by Massachusetts
Institute of Technology
Source: Eye
tracking and brain signals reveal how some skills become second nature
