First impressions are largely about style. Style, or the lack of it, has more impact on hiring than substance. The real problem is that once we accept or reject a candidate, the evaluation process shuts down. The quicker this happens, the less new information we seek out and process. We still go through the motions of asking questions, but we either use the answers to support our first impressions or ignore them if they seem to conflict.
Emotions play a powerful role in the interviewing process.
Unfortunately, the role they tend to play is negative. Past Performance is the Best Predictor of Subsequent Performance . Biases about age, physical characteristics, and even race can easily override a candidate's strong points. Try to remember that nobody is really at their best during an interview. Even the seasoned professionals get anxious or tense.