Your Brain on Fast Food

Some kids more readily recognize Ronald McDonald than the President of the United States of America. Sad, right?

Check out this exchange, from the 2004 movie Super Size Me:

Morgan Spurlock: [to kids] I'm gonna show you some pictures and I want you to tell me who they are.
Children: OK.
Morgan Spurlock: [Showing a picture of George Washington] Who's that?
Child: George Washington?
Morgan Spurlock: Good. Who was he?
Children: He was the 4th president. He freed the slaves. He could never tell a lie.
Morgan Spurlock: [Shows picture that you can't see] Who's that?
Child: George W. Bush?
Morgan Spurlock: No. That's a good guess though.
[Shows picture and its a picture of Jesus]
Morgan Spurlock: Who is this?
[Shows a picture of Wendy]
Child: Wendy!
Morgan Spurlock: Nice!
Morgan Spurlock: Who's that?
[Shows picture of Ronald MacDonald]
Child: MacDonald, Ronald MacDonald.
Child: MacDonald!
Morgan Spurlock: What does he do?
Child: He helps people at the cash register.
Child: He works at MacDonald's. I love the pancakes and sausage!
Child: He brings everyone of his friends to McDonald's for a Happy Meal
Morgan Spurlock: Where have you seen him?
Child: On television, on the commercials.
Child: He's the character that made McDonald's, and he does a lot of funny stuff on TV.

You're probably not surprised that we readily recognize symbols of the fast food that is so ubiquitous in our society. But would you believe that even a brief subliminal delivery of those symbols can actually affect the your behavior, even when it comes to things having nothing at all to do with eating or food?

Make sure your seatbelts are fastened, this is going to be a wild ride.

Experiment 1:
Previous studies have demonstrated that brief exposure to stimuli can alter social behavior. In one study, participants saw pictures of a fine dining restaurant and subsequently behaved with better manners in an eating task.

In this experiment, the experimenters wondered whether brief exposure to fast food stimuli would alter reading speed.

First, the participants read a short paragraph unrelated to food. This was used to determine a baseline reading speed. Then, they did a lexical decision task - in this sort of task, words are flashed quickly on a computer screen, and the individual must decide whether or not the stimulus flashed was a real word (e.g. tube, wind, sock) or a made-up nonword (e.g. zube, dind, solk). But the experimenters didn't actually care about their responses to this task because while they were doing it, in the corners of the screen, flashing objects were presented subliminally for just 12 milliseconds. In the fast food condition, these were fast food logos. In the control condition, they were just colored squares.

By flashing the images so quickly, the experimenters were able to ensure that their perception did not reach consciousness. After this experimental manipulation, participants were given several paragraphs to read on the computer screen, and the time taken to read the entire passage was recorded.

After the experiment was over, participants in BOTH conditions reported that they simply perceived colored blocks in the corners, but nothing meaningful.

The individuals in the experimental group, who were subliminally exposed to fast food logos, read the passage significantly faster than the control group, even after controlling for baseline reading speed. It should be noted that there was no time pressure in the reading task. Despite this, at the unconscious level, exposure to fast food stimuli increased reading speed by an average of 15 seconds.

Experiment 2:
This experiment addressed a different form of impatience: preference for time-saving devices. According to the experimenters, the extent to which an object saves time is only one of many variables to consider when choosing between two alternatives. Others are environmental friendliness, color, quality, and so forth.

First, participants were asked to recall a time that they ate at a fast food restaurant (experimental condition) or went to the grocery store (control condition). Then, they were given a "marketing survey" in which they rated the desirability of eight products from 1 (not at all) to 7 (highly desirable). The items to be compared were things like a four-slice toaster and a single-slice toaster, or a 2-in-1 shampoo and a regular shampoo.

As expected, participants primed with fast food imagery desired time-saving products more than their alternatives. Those in the control condition showed no difference between time-saving and standard products. The authors conclude that thinking about fast food makes people impatient and strengthens their desire to complete tasks as quickly as possible.

Experiment 3:
This experiment investigated the potential relationship between fast food and willingness to save money.

First, participants were asked to rate various aesthetic aspects of logos. The logos in the experimental group were from popular fast food chains, and in the control group were from popular local diners. This way, the logos were matched for inexpensiveness but not for time efficiency. Then, they were given options to receive money at different times. Each choice was between receiving "$3.00 today" and "X in one week," where X was $3.05, $3.10, $3.25, $3.50, $3.75, $4.00, $4.50, $5.00, $5.50, $6.00, or $7.00.

Participants initially exposed to fast food logos required a much higher X value in order to prefer to wait a week. In other words, they were more likely to accept a smaller payment today than a larger payment next week. Fast food seems to have made people impatient to a point where they could potentially put their economic interests at risk.

This is interesting, but why does it matter?
Fast food represents the pinnacle of time efficiency and instant gratification, but the consequences of fast food's ubiquity in modern culture are not completely understood.

This research suggests that the behaviors elicited by exposure to fast food-related stimuli are automatic and context-independent. Exposure to fast food might increase reading speed at work (where this might be useful) or at home (where this might not be useful). I wonder if seeing all the gigantic signs and billboards advertising fast food on the streets and freeways makes people drive faster (this would be a really really interesting study, with really important implications!)

Is fast food another result of a cultural drive towards time efficiency and impatience, or is it the cause? This is an open question. But given this evidence, it seems pretty clear that the fast food culture that we live in not only changes the way people eat but also fundamentally changes the way they experience things. If it can make you read faster, what else can it do? Fast food might have a much broader impact on human behavior and decision-making than previously considered.

Zhong CB, & Devoe SE (2010). You are how you eat: fast food and impatience. Psychological science : a journal of the American Psychological Society / APS, 21 (5), 619-22. PMID: 20483836