Have you ever looked down at your shopping cart during a grocery store trip and thought, “Why did I choose these items?” After all, supermarkets carry thousands of products (according to the Food Marketing Institute, the median number is 42,214), and you could have selected any of them. What made you decide to pick these specific products?

When asked, most people will try to come up with logical reasons – I ran out, I like this brand, my friend recommended it, it was on sale, etc. But eye tracking research reveals that many purchase decisions aren’t driven by logical considerations; in fact, they aren’t driven by conscious consideration at all. Most of our shopping choices are made on a subconscious level, triggered by a combination of perception and emotional response.

This subconscious buying behavior, which we’ve observed consistently in our eye tracking studies, has enormous implications for brands and marketers, affecting everything from package design to advertisements to shelf placement. Understanding how the subconscious mind interacts with a product could be the key to its success.

The Subconscious Mind

The word “subconscious” literally means below awareness. This level of the mind is not well defined or understood, but it nevertheless has tremendous power over human perception and behavior. Almost all brain activity happens on a subconscious level. Estimates vary, but perhaps a mere 10 percent of information ever reaches the conscious mind. As Freud put it, “The conscious mind may be compared to a fountain playing in the sun and falling back into the great subterranean pool of subconscious from which it rises.”

One of the difficulties in assessing subconscious behavior is that, once we start actively thinking about it or talking about it, it’s not subconscious anymore. The best way to catch the subconscious mind in action is to observe a subject’s natural behavior, such as with eye tracking.

Eye Tracking

Eye tracking allows us to precisely observe what shoppers are looking at and how that affects their decision-making. We ask shoppers to wear a small headset with a built-in camera that catches even the most minuscule eye movements. The eye tracking devices we use are unobtrusive, so shoppers can easily go about their usual grocery ritual. 

After shoppers complete the shopping trip, we often survey them about their shopping experience. We also watch the video with shoppers and ask them what they were thinking in each moment. 

When we analyze the data and compare it with the shoppers’ conscious thinking and recollections, it becomes clear that the vast majority of visual information travels through the eyes into the subconscious mind and never reaches the conscious level. But it’s also clear that the information stored in the subconscious is influencing buying behavior.

Vast Visual Onslaught

Think about how much information is in front of your eyes in a grocery store: colors, shapes, movement, lights, pictures, text and more, all vying for attention. Your eyes are remarkably good at filtering the information and bringing the important stuff to your conscious mind: “You’re about to run into that shelf” or “That cake looks yummy” or “Those cans of soup are three for the price of one.” 

But before any of those thoughts reach the surface, that information is just part of the “subterranean pool” of visual data that your eyes filter into your subconscious mind. And in order for data to make it even that far, your eyes have to take it in.


When observing a scene, your eyes move abruptly, not continuously. Movement occurs every three to six seconds, and in between your eyes are still. The movements, called “saccades,” last about 20 to 40 microseconds, and you are likely unaware that they are happening at all. The still periods, which last 100 to 400 microseconds, are called “fixations.” Your brain can only take in information from fixations – anything seen for under 200 milliseconds is lost. 

The fixation location is very small; you can only perceive information approximately two degrees around it. Beyond this narrow area of focus, visual information turns coarse and fails to get processed. 

When we watch eye tracking videos, we can see when the shopper’s eye is in fixation mode and what it fixates on. From that information, we can diagram a surrounding area within two degrees of the fixation point to illustrate everything that the shopper saw. This is the information that was sent to the subconscious mind.

The Consideration Set

Shoppers can fixate on a tremendous number of items in a short period of time. In one study we performed in a music store, one subject fixated 245 different times in five minutes. That’s 49 items per minute. In a half-hour trip, the shopper would have some 1,800 fixations. The subconscious mind can take in that much information, but processing it into conscious thought and memory would be impossible. 

When you shop, your subconscious mind is constantly filtering information into a “consideration set” of items that could be worth bringing to the conscious level. Grocery stores tend to arrange aisles and shelves in a similar way, so the subconscious mind already knows approximately where the items of interest are. The cereal aisle is a good example: grocers put children’s cereal on the lower shelves so it will be at eye level for kids. Shoppers who don’t have children don’t even glance at the lower shelves. If a healthy cereal were placed there, the single adult would probably never see it and it would never enter the consideration set.

Another important thing that happens at the subconscious level is emotional and physiological reaction. When we combine eye tracking with biometric equipment that measures pulse, skin conductivity, brain waves and facial expressions, we can see which items cause which reactions: excitement, relaxation, confusion, positive emotions, negative emotions, etc. You may not even notice that you’re having these reactions, but they are strong enough that they can cause you to act. 

Getting to the Conscious Level

The goal of brands, of course, is to sell products. But in order to do that, you have to get shoppers to fixate on the product, subconsciously enter it in the consideration set, then consciously pick it up and put it in their basket. That’s a lot of steps, and tens of thousands of other products are competing with yours to get shoppers to do the same thing. So how do you increase the chances of your product making it through this chain of decision-making? By maximizing the chances of each step happening.

Shoppers are most likely to fixate on things that are located in a zone from 10 degrees above eye level to 30 degrees below it. Getting onto those shelves can be the key to getting fixation, especially for new products. Our eye tracking research has found that bright colors, images with faces and movement are also ways to grab the eye. 

Once you have fixation, you want to get into the consideration set. Placing your product near a competing brand increases the likelihood of shoppers considering yours instead. Private label brands know this and that’s why they place their items directly next to name brands. They are counting on shoppers noticing the brand name first, but taking the private label package into their consideration set.

This is where emotion can play a huge role; if a shopper has a positive emotional and physiological response to your product, he or she is more likely to consider purchasing it. When launching a new brand or redesigning a package, you may want to perform biometric testing to see how it makes shoppers feel. Many a product has launched and failed because its packaging caused the wrong subconscious reaction.

After your product makes the consideration set, it needs to beat the competition by being perceived as the better product. In many cases, a shopper will impulsively go for your product without much conscious consideration, but sometimes a conscious reason is needed. Is the price lower? Does the quality seem higher? Is it familiar from all those TV ads you ran? Is the picture or text particularly compelling? When we perform eye tracking studies and watch the video with shoppers immediately following the trip, we can identify which factors affected the conscious purchase decision for (or against) a product

Eye Tracking: The Key to Uncovering Hidden Motivations

Because so much of the shopping process happens below the level of conscious awareness, marketers have long struggled to figure out why consumers make the choices they do. Just asking people is of limited value because they don’t remember (or misremember) much of what they’ve seen. And they often don’t really know, or simply make up reasons to explain why they bought certain items. 

But modern technology is helping us uncover the mystery of how the subconscious drives shopping behavior. With eye tracking, we don’t have to rely entirely on someone’s story. We can see what happened through their eyes.