The Researcher is Present
A nice graphic from a New York Times article — An Appeal to Our Inner Judge — about the innate ability of our unconscious mind to create bias, assumptions and profiling; particularly as applied to people.
Identifying and factoring for inherent prejudice is essential in many aspects of user experience work; perhaps when recruiting new team members, meeting new clients but especially when working with research participants.
I also like how this graphic illustrates how many cognitive activities, conscious or otherwise, are undertaken by a researcher as they facilitate experience design sessions, particularly how many variables can be brought into play during a seemingly simple one-to-one interaction like a interview, let alone something more complex like a focus group or usability test.
In both cases being aware of the unspoken influence your inner judge will positively affect your ability to reach better outcomes and decisions for your project.