Samantha was excited about her new job in a diverse city. During her first week, she noticed that most of her colleagues tended to eat lunch with coworkers of the same ethnicity. Samantha, not wanting to feel left out, began doing the same. Months later, she realized she had formed negative biases about other ethnicities in the office based on casual conversations she'd had during these lunches.

Which theory best explains Samantha's newly developed biases?

Group of answer choices

In$-$group bias

Groupthink

Ethnocentrism

The mere exposure effect