It probably varies a bit by program. Based on observing the process as a grad student, it was never a question of choosing between a qualified interviewee and a likeable (but not qualified) interviewee. My mentor got maybe 50 applications each year, and by the time that pool was narrowed down to 5 interviewees, everyone who interviewed was certainly qualified. At that point, it really becomes a question of "which of these qualified individuals do I want to work with for the next 5 years?" It's not just about personality per se, but about choosing someone whose work/communication style seems like it would fit well with the POI and the rest of the lab.
...And I'd like to add: If it is a clinical, counseling, child/school psychology program who will train clinicians to assess, diagnose and treat other individuals with mental health issues, does the applicant give off a good vibe? Are they approachable, friendly, engaging, warm....does this applicant seem like someone you could build upon her/his knowledge base and throw her/him into a room with any person (the patient) suffering from delusional thinking, perceptual disturbances, acute trauma, history of childhood abuse, substance use or xyz (the list goes on and on...you get my point) and any person will feel like communicating his/her deepest thoughts, discussing his/her problematic behaviors, things he/she is denying or avoiding or troubling emotional experiences, and building trust with this applicant for the purpose of assisting the patient through the difficulties?
If an applicant appears mature and well-related enough for a POI to be proud of their scientist-transformed-clinician, then it boils down to who seems
more mature, the
most well-related, the
most engaging and approachable. And those are the ones you find with the most offers. *Not to say those who did not receive offers lacked in 'people-skills,' but there may have been more qualified applicants who gave off a more friendly and warmer vibe.* You know the type? Those friendly, genuinely caring folks, who you want to spill your beans to in an elevator. And what do they have above and beyond their excellent CV? It can translate into compassion, kindness, empathy, genuineness...and all of the abovementioned qualities as well (i.e., strong CV).
Sounds like a tall order, but it's not necessarily, when you consider the work we do. Simply stated: the "like" factor pertains to the qualities one possesses, how they carry themselves (during the interviews and evidenced by relationships they've maintained with their letter-writers) , as well as what they accomplish...and some can become more likeable than others when you break it down in those terms. Knowledge and awareness in the field can be considered "book smart"...programs want an applicant to be savvy, mature and book smart. (Again not speaking to anyone specifically, but perhaps other applicants displayed more of these factors and also (maybe) had better luck... this time around.)
chai_latte, if you consider it this way...then, the "like" factor and personality may have not more pull than qualifications & demonstration of knowledge and awareness of the field, but actually become the deciding factor.