Why You Can See the Value of a Set of Objects at a Glance

Your beliefs about value affect what you see.

Posted Nov 18, 2020

The world can be a busy place. Walking down a crowded street, there is a sea of faces in front of you. Look in a shop window, and there is an array of objects for sale. Look up in the sky, and several birds might be flying past.

When you have a lot of time to look carefully at objects, you can (obviously) see a lot of detail. But you can also take in quite a bit of information about a collection of objects at a glance. You can determine whether the people in that sea of faces are generally happy. You can determine the typical direction the birds are flying in (even if some are flying in different directions). You can tell whether the objects in the shop window have a dominant color in common.

This ability to detect some qualities of a group with a single glance is called ensemble perception.

Are the qualities you detect from a glance like this limited to simple properties like color, movement direction, or facial expression? Could you also tell whether the objects are valuable?

This question was explored in a paper by Allison Yamanishi Leib, Kelly Chang, Ye Xia, Andy Peng, and David Whitney in the October 2020 issue of the Journal of Experimental Psychology: General. In one representative study from the paper, there was a set of 52 objects. These objects consisted of a high-priced and a low-priced object from each of 26 different categories of consumer products. For example, there might be an inexpensive candy bar and an expensive candy bar.

On each trial of the study, participants saw a set of objects flashed to the screen. There were 1, 2, 4, or 6 objects that were shown for one second. The objects shown were selected from the set of 52 so that there was at most one object from each category. The sets were selected so that over the course of the study, the sets varied in the overall value of the items in the set. After judging the value of 120 sets of objects, participants were shown each of the objects individually without time pressure and were asked to judge the value of the objects.

There are a few key questions in this study. First, are people able to detect differences in the overall value of an array of objects presented for one second? Second, are people trying to identify a small number of the objects they see, or are they actually getting information from most or all of the objects that are presented?

People are able to detect differences in the value of objects presented quickly. People’s judgments on each trial were compared to the values that they gave to the objects later in the study. Overall, people’s judgments of the value of the items in the set were generally high when the value of the objects in the set was high and low when the value of the objects in the set was low.

One reason that the number of objects shown on a given trial was varied was to see whether people who saw an array of 6 objects responded differently from those shown 1, 2, or 4. You might think that people can only take in information about 2 or 3 objects at a glance. If so, then you would expect that adding more objects would actually make people’s judgments of the value of the set get worse, because they wouldn’t be taking the whole set into account. In fact, people’s judgments for sets of 6 objects suggest they are able to use information from more than 4 of the objects in making their assessments. So, people are taking in a lot of information at a glance.

Another study in this series suggested that people cannot explicitly remember that many of the objects they saw, so they aren’t making this judgment by recalling exactly what they saw and then using that information to make their judgment of value. Instead, it appears that people have an association between features of objects (including brand names) and value and that they are able to get a quick sense of the overall value of what is there.

It might seem strange that people are quickly able to associate what they see with value. Remember, though, that value doesn’t really refer to money (which is a relatively recent invention), but value to a person based on what they can do with the object. It is an important skill to be able to tell at a glance whether there are objects present that would help someone to achieve their goals.

Of course, this does demonstrate the deep relationship between perception and learning. We don’t come pre-programmed as babies to know about the features that determine whether coffee, electronics, or shoes are valuable. Instead, we learn that through our personal experience and through the information we encounter. Advertisers pay for access to our brains in order to give us information about value that will influence our behavior. It might be scary to contemplate, but that advertising reaches all the way through our cognitive systems to affect the way we see the world.


Yamanashi Leib, A., Chang, K., Xia, Y., Peng, A., & Whitney, D. (2020). Fleeting impressions of economic value via summary statistical representations. Journal of Experimental Psychology: General, 149(10), 1811-1822.