Genetic contribution to distractibility helps explain procrastination

By Dr. Liji Thomas, MDJul 14 2019

Wouldn’t it be nice to blame your genes for your procrastination? Now, using a combination of questionnaires and genetic testing, German researchers have found that with increasing dopamine in the brain, women tended to show greater tendencies to procrastinate.

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Procrastination is defined as voluntarily putting off certain goal-oriented activities. People who do things at once rather than putting them off show good metacontrol, which is a combination of control over cognition, motivation and emotions. This allows the individual to assess how much effort and control goes into achieving a particular goal, which drives the action towards that goal. These control pathways have been associated with dopamine release in the brain.

When metacontrol is poor, people allow other activities to distract them from the specific action required to meet their goal, and develop chronic procrastination. However, metacontrol is intimately dependent on reward pathways and value-based processing. It also requires efficient guarding against competing information.

The Bochum-based research team: Professor Onur Güntürkün, Caroline Schlüter, associate professor Dr. Sebastian Ocklenburg, Dr. Marlies Pinnow and Dr. Erhan Genç (from left). Image Credit: Kramer

Dopamine has been repeatedly shown to increase the speed with which data enters the working memory, which is used to perform current tasks. At the same time, it also enhances cognitive flexibility. Cognitive flexibility makes it easier to update the working memory and to switch tasks by enabling a broader field of attention. While these are not intrinsically negative traits, the availability of more information on current happenings in the environment could serve to distract from the intended task or to put off an action. This impacts the individual’s capability of sticking to a planned course of action.

On the other hand, dopamine is also related to increased stability of the working memory which makes it easier to achieve goal-directed actions. These actions are achieved by dopamine activity in different areas of the brain. The first improves the signal-to-noise ratio allowing information relevant to the goal to predominate. The latter involves increased reward prediction, more updating of working memory, and increased distractibility, promoting procrastination.

The study was published in the journal Social Cognitive and Affective Neuroscience on 3 July 2019.

Building on earlier studies, which showed that good connections between the regions of the brain called the amygdala and the dorsal anterior cingulate cortex (dACC), as well as reduced amygdala volume, were related to goal-directed action, the researchers aimed to find out if the TH gene was involved in this correlation.

The scientists looked at almost 280 men and women, especially focusing on the gene encoding the enzyme tyrosine hydroxylase (TH). The expression of this gene determines the amount of various catecholamine transmitters the brain contains, including dopamine.

Alongside the genetic testing, a questionnaire-based evaluation was made of how well people in this group could do what they set out to do. The answers were used to measure the levels of decision-related action control, or AOD. The results showed that women who showed a trait-like inability to  control their actions as they intended, or in other words, trait-like procrastination, had higher expression of the TH gene. However, there was no association between the earlier findings of increased amygdala volume and functional connectivity with the TH genotypes, though their positive correlation with procrastination was confirmed.

Study author Caroline Schlüter says, “We assume that this makes it more difficult to maintain a distinct intention to act. Women with a higher dopamine level as a result of their genotype may tend to postpone actions because they are more distracted by environmental and other factors.”

The fact that this difference was noted only in women is remarkable. However, older studies have shown that the expression of the TH gene is related to behavior in different ways depending on gender. This is perhaps linked to the presence of estrogen in women. This female hormone has an effect on the synthesis of dopamine in the brain, as well as enhancing the number of neurons that respond to signals from dopaminergic neurons. Genc says: “Women may therefore be more susceptible to genetic differences in dopamine levels due to estrogen, which, in turn, is reflected in behavior.”

Future directions of research include a more quantitative assessment of how estrogen levels impact the behavior-TH gene axis. The hormone fluctuates in women of reproductive age, throughout the monthly cycles. Another area in which the researchers are interested is the influence of the TH gene on norepinephrine, another well-known neurotransmitter, which also affects action control or postponement.