There was no conscious prejudgement to remove from your behaviour. Humans like to fit in, and like to be informed. The human brain is fantastic at adapting to new situations because of its ability to infer information from past experiences. Put me in a high pressure meeting where the stakes are high and multiple people I don't know, and my brain will be working overtime to help me out. And that may involve my brain using my past experiences to feed me information that it thinks will help me. Such as identifying the roles people play. If I have only ever met white CEOs, or perhaps even if most people in my social circle are white, it is not unreasonable for my brain to infer that the CEO is white. Nothing racist about it. It would be racist for me to then consciously assume that the black person is less qualified to be the CEO purely based on their skin color, but that's not what would've happened initially.