When interviewing candidates for your open job, beware of these five nearly universal cognitive biases that may lead you to overestimate someone’s ability to do the job.

1. The Halo Effect

This is the tendency to quickly like (or dislike) everything about a person – especially on traits or competencies you have not observed or evaluated. You expect to see (or not see) something, and through confirmation bias, believe there is evidence when there might be none.

In hiring, this often plays out when an interview is going well. The hiring manager might pass over a key evaluation point, making the assumption that the candidate will also be competent in it, due to other competencies already established.

2. Blindspot Bias

This is when you fail to see the impact of your own personal biases on your judgement.

A recent research study asked 661 adults whether they are more biased than the average person. Of that 661 people, only 1 said they were more biased than average. As one of the researchers concluded, “Whether a good decision-maker or a bad one, everyone thinks that they are less biased than their peers.”

3. Overvaluing Passion

There is a tendency in interviews to favor the charming, and equate charm and enthusiasm with a candidate’s passion for the job.

But that instant-on enthusiasm and “fast on their feet” charm of an extrovert has little to do with true passion, and can quickly fade. Research shows that, over time, team members often prefer the quiet, low-key diligence of an introvert.

Because passion is better defined by grit – demonstrating resilience, persistence, and determination. The most passionate candidates might be misfit toys. They might be a bit awkward during the interview. They may not invest much attention in a charm offensive, but they will light up once you get them talking about projects and metrics and obstacles overcome. (Read Parsing Passion in the Interview.)

4. The Dunning-Kruger Effect

The candidates who are least competent will act (and probably believe) themselves the most confident in their abilities.

In hiring, this is most relevant to the self-evaluation. For example, say you ask each of your candidates to rate their ability to use Excel on a scale of 1 to 10. Those who have used it only a bit will often evaluate themselves very highly. While those who are experts or have used it extensively will rate themselves more accurately, which often means they will pick a lower score. This is because experts know how much they don’t know. While candidates less skilled, blind to the depths of what they don’t know, will demonstrate undeserved confidence.

5. Fundamental Attribution Error

Wharton professor Peter Capelli describes this bias as:

“A very common bias where we assume that the actions of individuals are caused by who they are rather than the circumstances around them: The car speeding past us on the shoulder of the road is always being driven by a jerk and never by someone who has an emergency. Hence, we see employees performing poorly as being chronically bad employees.”

This is a crucial bias to understand. If we assume someone’s successes are due to an inherent personal trait, and do not consider the context surrounding their successes, we often then believe that their successes are transferable to a new environment. Rarely is this the case.


The best way to overcome cognitive biases is to ask better questions during the interview, and then debrief more methodically after the interview. The structure of the conversations will help focus your mind on relevant factors and diminish the role of extraneous factors. Also recognize that video interviews scramble the hiring decision in new ways, introducing even more factors unrelated to predicting job performance.

For more how to overcome biases and hire more effectively, download our Case for Competency-Driven Interviewing and Employer Guide to Interviewing for a step-by-step guide to interview success.