Quit any habit by leveraging your brain’s desire for self-preservation

Would you touch a hot stove? Not willingly. The moment your fingers got close, your mind would be screaming hysterically, “STOP! DON’T DO IT! IT’S GONNA HURT!”

Your mind reacts that way because at some point in your life, you probably touched something that was a little too hot for your tastes. Being geared towards self-preservation, your mind decided to associate the idea of “hot”, with the feeling of “pain” that it delivered. That pain served as “aversive conditioning” to teach you that you shouldn’t touch hot things without adequate protection.

Around 80 years ago, scientists started experimenting with using aversive conditioning to break habits, addictions, and compulsive behavior. One such study focused on nail biting.

Habitual nail biters quit habit using “aversion”

A study from the University of Wisconsin-Milwaukee (Vargas, Adesso, 1976) compared the effectiveness of three alternative approaches on treating chronic nail biting: electric jolt, negative practice, and bitter substance.

A number of volunteers who had been biting their nails for an average of 12 years, were randomly and evenly distributed into 4 groups.

The first group received “electric jolt conditioning”. During the sessions, these participants were to bite their nails on command, upon which they would receive an unpleasant jolt from a device connected to their fingers using electrodes.

The second group received “negative practice”. Negative practice involves repeatedly practicing the wrong behavior (in this case nail biting) with the full knowledge of it being wrong. This is done with the premise that “repetition of a wrong response knowingly, may increase the probability of occurrence of the right response” (Peak, 1941).

The third group received “bitter substance conditioning”, which involved applying a bitter-tasting substance to their nails and then biting them.

The 4th group was given no treatment whatsoever. In scientific research, this is called a “control group”. It helps researchers understand whether the changes happening in the test groups are due to the experiment, or to external factors.

The members of every group had their nails measured before treatment and at the end of the treatment. Additionally, half of the participants in each group were asked to regularly measure their own nail growth.

Participants in “bitter taste” and “electric jolt” groups register much higher nail growth at the end of the treatment

After six sessions of treatment, participants in the groups receiving electric jolts and bitter taste treatment experienced a much greater nail growth than those within the “control” group. The negative practice group also achieved good results.

shock vs nailbiting

Interestingly, those participants who were regularly monitoring their own nail growth were even more successful than those who weren’t.

Awareness + Aversion = Habit Breaking Bomb

The study above shows that when an aversive stimulus (such as an electric jolts or bitter taste) is linked in some way to a behavior, the mind starts to reprogram itself to stop that behavior. This is similar to the example of the hot stove mentioned earlier in the article.

More importantly, awareness of the behavior considerably enhances the effectiveness of this approach.

Strictly speaking, awareness rarely is enough. Most of us are very aware of our bad habits, but it doesn’t help us quit.

That’s why we need both awareness and an “aversive stimulus” to succeed.



Coleman, James C., and Jean Elizabeth Mccalley. “Nail-Biting among College Students.” The Journal of Abnormal and Social Psychology 43.4 (1948): 517–525. Web.

Vargas, John M., and Vincent J. Adesso. “A Comparison of Aversion Therapies for Nailbiting Behavior.” Behavior Therapy 7.3 (1976): 322–329. Web.


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