You have spent hours eliminating every "um" and "uh" from your presentation. You have rehearsed until your delivery is smooth as polished marble. You deliver it flawlessly. And then, a week later, nobody remembers a word you said.
Meanwhile, your colleague stumbles through their presentation with the occasional "um," pauses to collect their thoughts, and somehow their message sticks. This is not bad luck. It is neuroscience working exactly as designed.
The Research That Changes Everything
In 2011, psychologists Scott Fraundorf and Duane Watson at the University of Illinois ran an elegant experiment. They wanted to know whether those "ums" and "uhs" we are told to eliminate actually serve a purpose.
The researchers took passages from Alice in Wonderland and created three versions: one delivered perfectly fluently, one with natural filler words ("um," "uh") digitally spliced in, and one with coughs of identical duration where the fillers would be. Participants listened to the stories, then their recall was tested.
Here is where it gets fascinating. Coughs of the exact same duration did not just fail to help. They actively impaired recall by 36%. This rules out the simple explanation that any pause or interruption aids memory. Filler words do something unique.
The findings held across two experiments with 114 total participants, using rigorous multi-level statistical modeling. This was not a fluke.
Why "Um" Works Better Than Silence
Your brain treats filler words as meaningful signals, not noise. When a speaker says "um," your auditory system interprets it as a message: "Important information coming. Pay attention."
This interpretation triggers what researchers call heightened attention allocation. Your brain actually shifts into a more active listening mode. Fillers function as natural attention cues, prompting listeners to encode the following information more deeply.
Think of fillers as the speaker's punctuation marks. They give listeners micro-moments to consolidate what they have heard and prepare for what is coming. Perfectly fluent speech, delivered without these natural markers, can actually overwhelm the listener's processing capacity.
Practical Applications
1. Stop the Perfectionism
A speech with natural hesitations will be remembered better than one polished to robotic smoothness. Your goal is message retention, not flawless delivery metrics. The research shows that eliminating every trace of disfluency may actually undermine your communication goals.
2. Recognize the Difference Between Natural and Excessive
There is a meaningful distinction between types of filler usage. A few strategically placed fillers signal thoughtfulness and give your audience processing time. Fifteen "ums" in one sentence signals preparation problems and overwhelms the attention cueing mechanism. The research supports natural speech patterns, not verbal tics.
3. Focus Your Energy Elsewhere
Time spent eliminating every filler might be better invested in clarifying your core message or strengthening your examples. The Fraundorf and Watson research suggests that the "perfect fluency" goal may be misguided. Natural speech patterns serve a cognitive purpose.
The Bottom Line
The quest for "perfect" speech may be undermining your communication goals. Fraundorf and Watson's research demonstrates that the very hesitations speakers fear are actually cognitive tools that help audiences remember. Your "ums" are not weaknesses to eliminate. They are memory anchors that make your message stick.
The next time you beat yourself up over a filler word, remember: your audience's brain just paid closer attention.
Put This Into Practice
Understanding the research is valuable, but finding your personal balance takes practice. Too few fillers and you sound robotic. Too many and you lose credibility.
The goal is not zero fillers. The goal is intentional, natural speech that serves your message.