interviewmochiStop Saying "Um": The Science Behind Filler Words in Interviews
You walk out of an interview feeling confident. You answered every question, smiled at the right moments, and even made the interviewer laugh. But there's one thing you didn't notice: you said "um" 47 times in 30 minutes.
Filler words—those little "ums," "uhs," "likes," and "you knows"—are the silent saboteurs of interview performance. While you're focused on what you're saying, hiring managers are unconsciously counting how often you pause to search for words.
Here's the science behind why we use them, how they impact your chances, and three proven techniques to eliminate them for good.
Why Your Brain Reaches for "Um"
Filler words aren't a sign of low intelligence or poor preparation. They're actually a fascinating window into how our brains process language under pressure.
The Processing Gap: When you speak, your brain is doing three things simultaneously: retrieving information, formulating sentences, and controlling your vocal cords. Filler words emerge during the microseconds when retrieval lags behind speech. Your mouth keeps moving while your brain catches up.
The Anxiety Amplifier: Stress hormones like cortisol actually slow down your prefrontal cortex—the part responsible for word retrieval. In high-stakes situations like interviews, your brain literally works slower, creating more gaps that get filled with "um."
The Social Placeholder: Linguists call filler words "discourse markers." They signal to the listener: "I'm still talking, don't interrupt." In conversation, they're actually useful. In interviews, they backfire.
Studies show that speakers use 50% more filler words when they can see their listener's face. The pressure to maintain eye contact while thinking creates cognitive overload—exactly what happens in interviews.
The Hidden Cost in Interviews
Here's what hiring managers won't tell you: they're not consciously counting your "ums." But their brains are.
Perception of Competence: A 2018 study from the University of Pennsylvania found that candidates who used more than 6 filler words per minute were rated 15% lower on "executive presence" and "confidence"—even when their answers were identical to candidates who used fewer fillers.
The Credibility Gap: Filler words make you sound uncertain. When you say "I, um, led a team of, like, 10 people," the interviewer's brain registers hesitation. Are you unsure about the team size? Are you exaggerating?
The Distraction Factor: Excessive fillers shift the interviewer's attention from your content to your delivery. Instead of thinking "great answer," they're thinking "that's the fifth 'um' in this response."
Three Techniques That Actually Work
The good news? Reducing filler words is a skill, not a personality trait. Here's how to train yourself:
1. Replace "Um" with Silence
This sounds simple, but it's the most effective technique. When you feel an "um" coming, close your mouth and pause for 1-2 seconds instead. The silence feels longer to you than to the interviewer. Practice this while recording yourself—you'll be shocked at how natural the pauses sound on playback.
Pro tip: Take a breath during the pause. It gives you oxygen (which helps your brain) and makes the silence feel purposeful.
2. Slow Down Your Speaking Pace
Most people speak 20-30% faster in interviews due to nerves. This creates more processing gaps, which means more fillers. Aim for 140-160 words per minute (about 2.5 words per second). This gives your brain time to stay ahead of your mouth.
Try this: Record yourself reading this article out loud. If you finish in under 4 minutes, you're speaking too fast.
3. Practice Out Loud (Not in Your Head)
Your brain doesn't use filler words when you think through answers silently. The problem only appears when you speak. That's why mental rehearsal doesn't work. You need to practice answering questions out loud, ideally while recording yourself.
The first time you hear yourself say "um" 15 times in a 2-minute answer, you'll be motivated to fix it. The second time, you'll catch yourself mid-"um." By the fifth recording, you'll naturally pause instead.
Ready to Practice?
InterviewMochi analyzes your filler words in real-time and tracks your improvement over time. Get instant feedback on every practice session.
Try Free (5 Recordings)The Bottom Line
Filler words are a habit, not a flaw. Your brain uses them as a coping mechanism when processing speed can't keep up with speaking speed. The solution isn't to think faster—it's to speak slower and embrace strategic silence.
Start by recording yourself answering one interview question. Count your filler words. Then record the same answer again, consciously pausing instead of saying "um." You'll hear the difference immediately.
With just 5-10 practice sessions, you can reduce your filler words by 60-80%. That's the difference between sounding nervous and sounding confident—without changing a single word of your actual answers.