There are many theories for the formation of relationships, including reward/need satisfaction theories and the filter model.
The reward/need satisfaction theory as proposed by Bryne and Clore, states that we form friendships and relationships to receive rewards/reinforcement from the others. Relationships provide rewards that satisfy our social needs. Rewards include things like approval, sex, status, love, money, respect, agreement with our opinions, smiling etc. Our social needs are things like self-esteem, affiliation, dependency, influence etc. Receiving rewards and having our needs satisfied, motivates us to continue the relationships.
The theory combines the principals of operant conditioning (Skinner) and classical conditioning (Pavlov). Operant conditioning proposes that we will repeat any behaviour that provides us with reinforcement- in this case of relationships, being in a relationship is positively reinforced because it is rewarding. Classical conditioning proposes we learn through association-this can also be applied to relationships. When we meet someone in a positive mood, we are more inclined to like them. Therefore, a previous neutral stimuli becomes positively associated with a pleasant event.
A strength is that there has been research to support the claim that people are attracted to others due to reinforcement. For example, Griffitt & Guay found that when participants were positively evaluated (i.e. rewarded) on a creative task rated their like for the researcher as high. Furthermore, Griffitt & Guay also found support for the claim that we are attracted to people through association. In the same study, an onlooker was present when the researcher positively evaluated the participant- they also rated their like for the onlooker as high- support that we are attracted through association. This suggests that the principals of operant and classical conditional...