Final answer:
Research aligns with the adage 'Birds of a feather flock together', as people tend to form relationships with others who are similar to them, a concept known as homophily.
Step-by-step explanation:
Research on the factors contributing to building relationships most prominently supports the adage, "Birds of a feather flock together." This is due to the concept of homophily, which suggests the tendency for people to form social networks with others who are similar to them in background, attitudes, and lifestyle. Evidence from various studies, including those by McPherson, Smith-Lovin, & Cook (2001), indicates that we are more likely to become friends or enter romantic relationships with individuals who share similarities with us, as opposed to being attracted to our opposites.
The reason behind this phenomenon is quite straightforward. Sharing common interests, values, and backgrounds can make it easier to connect and form lasting bonds. This understanding aligns with the idea that proximity also plays a significant role in relationship formation; we are more likely to build relationships with those we come into regular contact with, as revealed by decades of research, with the work of Festinger, Schachler, & Back (1950) being notable in this respect.