social sciences

Self-control a limited resource: muscle analogy

It has been proposed that self-control is a limited resource. Which means that our self-control would diminish over the day. From the moment we wake up, we’re faced with choices. What do you want to wear? What are you going to eat for breakfast? What time are you going to leave for school or work? And according to the muscle analogy, put forward by Baumeister, these choices get more difficult as the day progresses. We can’t use our muscles infinitely, just as we can’t use our self-control limitlessly. While there is new research that proposes that the muscle analogy might not be entirely accurate, I will describe one of Baumeister’s experiments that added scientific weight to the existence of his analogy.

An experiment with cookies and radishes
In 1998 a scientific article was published in which Baumeister was involved¹. His research team carried out different experiments to show that self-control is a limited resource. One of the experiments was carried out using cookies and radishes. The participants were 67 psychology students, who were told they were going to be studied on taste perception. This, of course, was a cover-up. When testing a hypothesis, you don’t want the test subjects to know what the researchers are looking for, as this might influence the results.
The researchers split the students into three groups, there was a control group (who didn’t eat any food), a radish group (they were asked to eat at least 2 or 3 radishes), and a cookie group (they were asked to eat at least 2 or 3 cookies). None of the participants were aware of belonging to a group and didn’t have a clue about what was actually being tested. And each participant was studied individually.But there is another catch! In the research room, they were baking cookies, so both participants in the radish group and cookie group were exposed to the delicious smell of fresh baked cookies.
Moreover, in the room, there was a bowl with cookies and a bowl with radishes. So, imagine you were assigned to the radish group and there is a delicious cookie aroma all around you, but you’re asked to only eat radishes. My wild guess is that if you had the choice, you would go for the cookies instead of the radishes. But the experiment doesn’t stop there! After eating radishes or cookies, the participants were asked to solve a puzzle. And again, there’s a catch. The puzzle is unsolvable.
The researchers compared the participants who were assigned to the different groups. In line with the muscle analogy, they found that those who were asked to eat radishes were more likely to give up easily. The researchers explain that this is due to the fact that they already had to exert self-control before the puzzle, which used up some of their self-control.

1. Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource?. Journal of personality and social psychology, 74(5), 1252.

social sciences

Consumer choices #2 How we choose?!

Imagine you’re standing at the candy aisle again. You’re still looking for the best possible milk chocolate bar. So far we’ve seen that having too many options might not be very beneficial for your actual choice outcome. But how will you end up choosing?

I’m assuming that in your lifetime you’ll end up being involved in more choices than just trying to find tasty chocolate bars. You are probably aware of the fact that you’re looking at different options… all day. Should I read this entire blog post? What am I going to eat for dinner? What time should I set my alarm clock? Should I take the job?

If we look at ‘making choices’ in a consumer perspective, it’s interesting to look from a brand’s perspective. Say you’re trying to sell a new product, but there’s already fierce competition from other brands in the same market branch. How are you going to advertise your product to make it stand out? You will have to know how people process information. And multiple researchers have come up with different models on how and when we make choices.

A model that looks at information processing is the Heuristic-Systematic processing model (Chen, Duckworth, Chaiken, 1999). According to this model we have two different ways to process information.

  • First, we could take the heuristic route. This means we’ll use heuristics, these are simple rules of thumb to solve problems. When engaging in this type of processing, we might look at the packaging of the chocolate bars. In the Netherlands, we seem to have this unwritten rule that all milk chocolate is wrapped in blue. Relying on heuristics, we might grab the nearest bar with blue wrapping. We’re more likely to rely on cues, like the color of the packaging, when (a) the issue is not very important to us, (b) we’re under time pressure, or (c) not very motivated.
  • But we can also take the systematic route. Using this route, we’re trying to take in all available information, scrutinizing every detail, and analyzing everything. This way of information processing means using a lot of cognitive effort. In our candy aisle scenario, we would study all the bars, and look for information we find important. Are we into fair trade? Are we limiting ourselves to a certain amount of calories? Do we have a budget? We will compare every piece of information we find important. So when will we spend hours browsing the whole aisle? 1. When the matter is personally relevant to us (Chaiken, 1980)! And we’re just so incredibly passionate about the perfect bar of milk chocolate. 2. When we want to be accurate! So our bar can’t surpass 500 calories. 3. And when we have defense motivation! This means that we care a lot for judgments related to our ‘selves’. In our case, we are looking for chocolate brand that uses fair trade. Because we see ourselves as being nice to others on the planet.

A matter of self-control?
Let’s say you were visiting the grocery store to only get milk and cereal. Yet, you happened to pass the candy aisle and stop for a second. You’re telling yourself to continue walking to the check-out. Because for whatever reason (whether it be a specific diet, or budget reasons) chocolate wasn’t on your shopping list. But in a split second you do grab yourself a tasty chocolate bar. Why?!
Baumeister, Vohs, and Tice, (2007) have developed a model that explains how self-control might work. They use the ‘muscle metaphor’. Our self-control is referred to as a muscle, that will be depleted of energy after it has been used for awhile. So if you have been fighting off temptations all day (not getting angry, staying focused on your work, patiently waiting, etc) it will become harder and harder to practice self-control.
Researchers have even suggested that being low on blood glucose can decrease our self-control (Gailliot et al., 2007). So eating chocolate before shopping should help you refrain from impulse purchases.
Vohs, and Faber (2007) found that once participants’ were low on self-control, they were more likely to buy more and spend more money!

The supermarkets are manipulating you!
North, Hargreaves, and McKendrick  (1999) conducted a very interesting field experiment in a supermarket. This is an experimental setting in which people are looked at in their ‘natural habitat’. Supermarkets either played French or German music, and the experimenters checked to see if customers were more likely to buy French or German wine. And guess what? When French music was played in the background, more French wine was sold! This was also the case for the German wines. And after participants were asked if they were aware of the fact that their choices had been influenced by music, they reported not knowing about this at all!


Baumeister, R. F., Vohs, K. D., & Tice, D. M. (2007). The strength model of self-control. Current directions in psychological science, 16(6), 351-355.

Chaiken, S. (1980). Heuristic versus systematic information processing and the use of source versus message cues in persuasion. Journal of personality and social psychology, 39(5), 752.

Chen, S., Duckworth, K., & Chaiken, S. (1999). Motivated heuristic and systematic processing. Psychological Inquiry, 10(1), 44-49.

Gailliot, M. T., Baumeister, R. F., DeWall, C. N., Maner, J. K., Plant, E. A., Tice, D. M., … & Schmeichel, B. J. (2007). Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. Journal of personality and social psychology, 92(2), 325.

North, A. C., Hargreaves, D. J., & McKendrick, J. (1999). The influence of in-store music on wine selections. Journal of Applied psychology, 84(2), 271

Vohs, K. D., & Faber, R. J. (2007). Spent resources: Self-regulatory resource availability affects impulse buying. Journal of consumer research,33(4), 537-547.

Photo source: By Simon A. Eugster (Own work) [GFDL ( or CC BY-SA 3.0 (, via Wikimedia Commons