The human brain has been evolving over millions of years. Throughout that evolutionary process, the brain has adapted to act and react in a way that will improve the chances of its owner’s survival, as well as its owner’s ability to procreate. One important neurotransmitter involved in both of these pastimes (i.e. survival and procreation) is dopamine.

Dopamine is a neurotransmitter that is associated with motivation, learning and pleasure. The following research study investigates the role of dopamine in love.


Studies investigating love and attraction often use prairie voles as they are primarily monogamous animals. One study showed that if dopamine levels were artificially increased in a female vole’s reward pathways, she would show a preference for a male who was present at the time of the increase in dopamine, even if she had not mated with that male previously. This suggests that dopamine can increase feelings of attraction for a particular individual and perhaps drive a desire towards procreating with that individual.

Having a strong desire towards one individual and not many can have survival benefits for voles (and humans). Having a strong bond with one person could help improve the chances of the survival for the offspring because when it comes to parenting, two heads (and four hands) are better than one.

Fisher et al hypothesized that when people in love saw images of their beloveds (the person they’re in love with), the dopamine in their brains would increase in areas of the brain associated with motivation. They predicted that romantic love was not an emotion, but rather a motivation system that leads to emotions. They tested their hypothesis by using fMRI scans.

The researchers gathered a sample of 17 participants (10 females, 7 males) of an average age of 21 years old (range: 18 – 26). They collected their sample through word of mouth and by posting flyers asking for volunteers. All the participants were “in love” and the average age of courtship was 7 months (range: 1 – 17). To determine the duration, intensity and nature of the participants’ romantic love, the researchers interviewed each participant using a semi-structured format and the participants also completed a “Passionate Love Scale (PLS)”.

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This study also highlights the value of using fMRIs to study links between the brain and behaviour.

The researchers found that using photographs of participants’ beloveds was an effective method for eliciting feelings of romantic passion, so they used these in their study. The procedure followed four steps:

  • First, while in the fMRI, the participants were shown a photo of their beloved for 30 seconds.
  • This was followed by a 40 second distraction task (counting backwards in 7s from a high number).
  • Then a photo of an acquaintance was shown for 30 seconds.
  • This was followed by a 20 second countback task.

The duration of the fMRI scan was 12 minutes per participant, and afterwards the researchers found through interviews that during the time the participants were looking at a photo of their beloved they were engaging in romantic thinking and feeling.

The fMRI results showed that distinctly different parts of the brain were activated when the participants viewed photos of their beloveds versus acquaintances. When viewing photos of their beloveds, an area of the brain known as the right ventral tegmental area (VTA) was activated. This is a dopamine rich area of the brain and is part of the brain’s “reward system”. Prior research has shown this area of the brain is associated with “pleasure, general arousal, focused attention and motivation to pursue and acquire rewards.” (Fisher, 2005)

So if anticipation of rewards can motivate us to work, and thus survive, why would seeing a person we love increase levels of dopamine? Perhaps it’s a motivational drive towards that individual in order to procreate (have sex). After all, if we don’t have sex and procreate our genes won’t be passed on. Like other studies on monkeys that show dopamine in increases with the anticipation of reward (not just getting a reward), perhaps we anticipate the rewards of romantic love from a partner and so our brains are wired to drive us towards attaining those rewards.


Critical Thinking Questions

  1. Does this study suggest that love affects dopamine, or dopamine affects love?
  2. Why do dopamine levels increase when we see the person we are in love with? 
  3. According to these studies, how can dopamine influence human behaviour? 
  4. Why did they ask the participants to do the distraction task between photos? 
  5. What are the limitations in applying results from this study to explain how dopamine can influence behaviour?
  6. How might cognition influence dopamine levels, and vice versa?

References

Fisher, Helen. Aron, Arthur. Brown, Lucy L. “Romantic Love: An fMRI Study of a Neural Mechanism for Mate Choice.” The Journal of Comparative Neurology. 493:58-62 (2005) (Accessed from interwileyscience.wiley.com)