Reward theory of attraction

Conditioning creates positive feelings towards things and people linked with rewarding events.[1] In 1985,Pawel Lewicki tested this liking-by-association principle by conducting an experiment on students at the University of Warsaw. In the experiment, two pictures of women were given to the students. The students had to choose which of the two pictured women, "woman A" or "woman B", looked friendlier to them. The results showed an equal amount of students had chosen the picture of "woman A" over "woman B" to be friendlier. The students in the group who chose "woman A" had interacted with a warm and friendly experimenter who resembled "woman A" before choosing a picture. They ended up choosing "woman A" at a margin of 6 to 1. In a follow-up study, a researcher acted unfriendly toward half of the participants. The participants were then instructed to to choose one out of the two pictures. They almost always avoided the one who looked like the "unfriendly" experimenter.

In Griffit's study college students that evaluated strangers in a pleasant room liked them better than students who evaluated strangers in an uncomfortably hot room.

Helen Fisher and her colleagues conducted a neuroimaging study on men and women that had just "fallen madly in love". She hypothesized that there could be a connection between higher levels of central dopamine, or norepinephrine and less activity of central serotonin when an individual experiences romantic infatuation. Using functional magnetic resonance imaging (fMRI), they collected data on 10 women and 7 men that reported being in love an average of 7.4 months. These participants were in between the ages of 18 and 26 years old. Each participant was shown a picture of their loved one and in addition, a photograph of an emotionally neutral person. After they saw the picture, each person had to engage in a task to distract themselves and allow their mind to clear of strong emotions. For example, the subjects were given a large number, such as 9,471, and were instructed to begin counting in receding order in increments of 7. Over the course of the experiment, this procedure ran for a duration of twelve minutes and repeated six times. [6]

Fisher found that several regions in the brain had been activated. There was an increase in activity in the right ventral tegmental area (VTA), caudate nucleus, and postero-dorsal body. Several regions of our brains receive the chemical dopamine because of the activated cells in the right ventral tegmental area (VTA) that produce and distribute it. The ventral tegmental area (VTA) is fundamental to the "reward system" in our brain. This is known as the neural network connected with our sense of pleasure, arousal, focus, and motivation to seek and obtain rewards. Behaviors related to motivation and goal setting were found to be linked to the caudate nucleus that is part of the reward system stimulated by dopamine as well. [6]

In the year 2000, animal studies were conducted in which attraction is positively associated with elevated activity in central dopamine. In the experiment, a female lab-raised prairie vole was mated with a male, and formed a distinct preference for him associated with a 50% increase of dopamine.[7] When a dopamine antagonist was injected into the reward region of the brain, she no longer had the preference for the male.[6]

In 2005, Fisher and her colleagues conducted a second fMRI study to research the effect of romantic rejection and gain a better understanding of human emotions, motivations, and behaviors related to this kind of love. In the experiment, the subjects consisted of 10 women and 5 men that had been rejected by their person of interest but still had romantic feelings for them. These participants were shown a picture of their previous partner and of an emotionally neutral individual as well. Afterwards, the subjects were directed to engage in a distracting task in order to clear their minds from any intense emotions. Once the results were analyzed, Fisher observed that there were significant effects on the individual's nucleus accumbens, lateral orbitofrontal cortex, and anterior cortex as well. These regions in the brain were found to be linked with the body's dopaminergic reward system. Fisher's research suggested that dopamine remained activated in people that had been recently rejected romantically. Such activity, in part, corresponded to the neural regions in the brain that are connected to people's ability to take risks, experience physical pain, and regulate their emotions. [6]