After I received my undergrad degree in Interpersonal Communication with an Emphasis in Body Language and Nonverbal Communication from Florida State University I moved to Auburn Alabama to work on my Master's degree and Study with one of the leaders in the Field. On my first day of teaching, I was gobsmacked by my student's introductory speeches.
Most of my students graduated in the top ten of their high school and had many impressive accomplishments, but their speeches sounded to me like they were uneducated. In part because of their heavy hard-to-understand southern accents and how they dropped their ING's to say things like, "I went huntin'?" "I was fixin' to go to Florida for school but I got/in to Auburn." My students were smart and educated, and I quickly grew to love and respect them but my prejudice affected my first impression. I was studying body language and yet my stereotype of Southern speech still impacted my impression.
Here is just one of the many research studies that
show stereotypes affect job interview first impressions negatively.
https://www.sciencedaily.com/releases/2019/10/191021151540.htm
Michael W. Kraus et al. Evidence for the reproduction of
social class in a brief speech. PNAS, 2019 DOI: 10.1073/pnas.1900500116
FYI I also quickly began matching and mirroring their speech and when I visited friends in Atlanta halfway into my first semester at Auburn my friends immediately started teasing me about losing my INGs
I also found out most of my students graduated in the top ten in their high schools in Alabama because most of them came from small towns where there might only be ten students in the graduating class.