Phone screens are tests of sociability. Sociability is an inherently bipolar or multipolar activity, where participants speech, body language and tone are interpreted by other participants, digested, then fed back to the original participant in the form of more speech, body language and tone. We deem those who would score high in sociability to be charming, to have charisma. We deem them so because they have the ability to raise the sociability of those around them. By dent of their mannerisms, they make others feel confident in expressing themselves, and they are willingly to let minor faux pas slide.

We would thus expect a candidate being interviewed by a charismatic interviewer to score more highly than they would in the presence of a social dolt. This state of affairs brings into question the utility of phone interviews as measures of job performance.