Carol Kinsey Goman, Ph.DThere is a magician’s trick called the “Vanishing Ball Illusion,” in which a ball tossed in the air seems to disappear – but in reality is never actually thrown. The trick depends on the magician’s skill in creating such a strong expectation of the throw that the audience actually hallucinates having seen it. The trick works because we are psychologically programmed to see what we expect to see.It's called "confirmation bias" and it is the reason why making a good first impression is so crucial for any leader - because that impression tends to stick. Once people mentally label you as “likable” or “unlikable,” “powerful” or “submissive,” "competent" or incompetent," “trustworthy” or “devious,” everything else you do will be viewed through that filter.Confirmation bias highlights the mind's ability to focus on (or even hallucinate) those aspects of a person or situation that reinforce our preexisting beliefs. No where is this mental agility more prevalent than in the way we evaluate the body language of political candidates. And rarely have our opinions of the candidates been as polarized as in this election.In general, we look for leaders who exhibit two sets of nonverbal signals: status and warmth. When we see status cues (broad arm movements, physical height, bold stride, decisive gestures, etc.) we feel the leader has confidence and authority. When we see warm body language (smiles, raised eyebrows, head tilts, smooth gestures, etc.) we believe the leader is empathetic and caring.Both Hillary Clinton and Donald Trump display nonverbal behaviors that are considered "good" for a presidential candidate, both have body language challenges, and both have areas where their nonverbal strengths become liabilities. But these generalized strengths and weaknesses pale in comparison to the power of the beliefs and expectations of their respective supporters.Here is how partisan supporters most likely evaluated the very same nonverbal cues from the first presidential debate:Trump rolled his eyes, grimaced, and smirked -- although less so in the first half of the debate. If you like him, you tend to view these expressions as valid reactions to whatever Clinton said that he disagreed with. If you don't like him, the same behaviors are processed as irritating, discourteous, and childlike.Clinton's used a tight smile to discount many of Trump's statements. If you are a Clinton supporter, you probably viewed this as a controlled and professional reaction to a bully's taunts. If you prefer Trump, Clinton's smile looked supercilious and phony.Did Trump's interrupting seem assertive or rude? Was Clinton's backward head tilt a sign of contemplation or arrogance? And is there any body language signal that we all evaluate the same way regardless of our political preferences?In fact, there are very few nonverbal signals that aren't influenced by our biases. Blink rate is an exception -- perhaps because it is produced and evaluated almost totally subconsciously. Joseph Tecce, an associate psychology professor at Boston College, says that lower blink rate has predicted presidential winners for eight out of the last nine elections. The candidate who blinks the most during debates has lost every election but one since 1980, the exception being George W. Bush, the year he lost the popular vote. (Here Hilary Clinton should have gained a slight advantage because Trump has an average blink rate of 64 blinks per minute, while Clinton averages 40 blinks per minute. Although in this first debate, I saw a lot of blinking from her.)Blink rate aside, unless you and I were genuinely undecided about whom we preferred when we viewed Clinton and  Trump in the first presidential debate, it may have been physiologically impossible to stay neutral.So whose body language won the first debate?Most likely, whomever we hoped would win.[author]About the Author: Carol Kinsey Goman, Ph.D. is an international keynote speaker, leadership presence coach, expert on the impact of body language on leadership effectiveness, and author of "The Silent Language of Leaders: How Body Language Can Help - or Hurt - How You Lead.” She can be reached by email: Carol@CarolKinseyGoman.com or phone: 510-526-1727. [/author]