Affinity bias

Affinity bias, also known as the similarity bias, similar‐to‐me effect, and the mini-me syndrome, refers to an implicit cognitive bias where people are favorably biased toward others like themselves. Those similarities may stem from a multiplicity of personal attributes including similarity in appearance, race, gender, socioeconomics, and educational attainment. Affinity bias can hamper creativity and collaboration through insular thinking.

People with similar personalities, backgrounds, and experience are able to more readily form social connections.

The affinity bias is a form of the halo effect.

Workplace
Affinity bias is often present in the workplace and can lead to the subconscious filtering of candidates. In recruitment, candidates who attended the same university as the hiring manager may be given preference. When promoting candidates, a hiring manager may promote someone who shares a similar hobby, such as golf, over other qualified candidates. Though affinity bias may lead to unfair hiring and promotion practices, it can also serve to increase mentorship and endorsement such as through women's empowerment.

The bias can be mitigated by having managers find common ground with the employee, thus priming the manager to see the employee as part of their in-group. Firms can also counter the bias through implicit bias training and by having hiring and promotions be a data and metrics driven process.