I used to think the goal was to get the audience’s interest high and keep it there. High and sustained. A plateau at the peak. This seemed logical — if high interest is good and low interest is bad, then peak interest maintained throughout should be optimal.
Henning Nelms corrected this in his handbook Magic and Showmanship, and it’s one of those corrections that seems small until you see its implications everywhere. His formulation: entertainment occurs only while interest is rising. Not while interest is high. While it is rising.
A flat interest curve — even a high flat curve — is experienced as boring. Not as engaging at a consistent level, not as satisfying in its constancy. Boring. The experience of plateau is indistinguishable, neurologically, from the experience of decline. What the audience needs is not a high level but a rising trajectory.
This changes everything about how you structure a performance.
The Neurological Basis
This isn’t an arbitrary aesthetic preference. It reflects something fundamental about how attention and engagement work. The nervous system is calibrated for change, not for states. Neurons fire in response to novel or changing stimuli and habituate quickly to unchanging stimuli — even pleasurable ones.
This is why an initially delightful smell fades quickly, why a beautiful piece of music becomes invisible if it plays constantly, why the most comfortable physical position becomes uncomfortable if you maintain it without shifting. Sustained sameness produces adaptation, and adaptation produces the experience of nothingness — which, in the context of performance, registers as boredom.
Rising interest defeats habituation. When each moment is slightly more engaging than the last — when the trajectory is upward — the nervous system remains alert because it’s tracking change. The audience doesn’t habituate because they haven’t stayed long enough in any given state to adapt to it.
What a Plateau Feels Like from the Stage
I’ve felt this from the performer’s side, and it’s uncomfortable to describe because it’s so subtle. The audience is attentive. They’re watching. There are no obvious signs of disengagement — no phone checking, no side conversations, no visible restlessness. By any surface measure, the performance is working.
But there’s a quality of aliveness in the room that’s dropped. You can feel it if you’re tuned in. The energy that was present at the opening — that forward-leaning quality, that particular attentiveness that feels like the audience is with you rather than watching you — has changed into something more passive. They’re receiving rather than engaging.
And if you’ve been performing for a while, you know that this is the beginning of the slide. Not a crisis yet. But not good. The plateau has become a cliff.
The antidote is not to suddenly escalate — that’s too obvious, too desperate, and the audience can feel the manipulation. The antidote is structural: build the show so that the plateau never happens in the first place.
Designing for Rise
If the goal is a continuously rising interest curve, then every element of the performance needs to contribute to that rise. Every beat, every transition, every effect needs to be slightly more compelling than the one before it — not in the sense of raw impressiveness, but in the sense of narrative stakes, personal involvement, or conceptual development.
This is why standard variety-show structure — where each act is self-contained and roughly equivalent in impact — produces that specific plateau feeling. Act one lands. Act two lands at roughly the same level. Act three lands at roughly the same level. The curve is flat. It may be high, but it’s flat.
What Nelms is pointing toward is structure where each phase of the performance inherits the investment the previous phase built and adds to it. The stakes get higher. The audience’s personal involvement deepens. The conceptual territory becomes more interesting. So that by the time you reach the climax, you’re delivering to an audience whose interest has been rising throughout, not plateauing.
The Implication for Show Building
When I design a keynote performance section — the portion of a talk where I use magic and mentalism to illustrate a concept — I’ve started applying the interest curve explicitly. I ask: if I mapped the audience’s likely interest level against time, what would the curve look like?
I’m usually wrong in early drafts. What I think is a rising curve turns out to be: spike, plateau, spike, plateau, spike. Individual moments of impact separated by connective tissue that’s flat. The connective tissue is where the plateaus happen, and the audience is habituating during it even though they don’t realize it.
The fix is usually to make the connective tissue do more work. Not to add more impressive content to it — that changes the shape of the peaks but doesn’t change the overall trajectory. To make the transitions themselves interesting: to carry narrative stakes through them rather than stopping the stakes at the end of each phase and starting fresh.
This is structurally difficult because performers tend to think in effects — discrete units of impressive content — rather than in curves. Shifting to curve-thinking requires a different level of analysis. You’re no longer asking “is this effect good?” but “does this effect, in this position, at this moment in the show’s trajectory, advance the interest curve?”
The Opening Problem
The interest curve principle creates a specific challenge at the opening. If interest must always be rising, where do you start? If you start too high, you have nowhere to go. If you start too low, you risk losing the audience before the curve begins its ascent.
Nelms’ implication is that the opening should start at the minimum level that keeps the audience attentive and invested — and then every subsequent element should move the curve upward from there. The opening doesn’t try to impress. It creates the conditions for a sustained rise.
This is hard to execute because the temptation is to open with something strong. Open with your best material. Grab them immediately. But grabbing them immediately means starting high, which means having to sustain that high level or maintain a rise from an already-elevated starting point — a structural problem.
The alternative is an opening that’s engaging in a different way than impressiveness: curiosity, identification, a premise they recognize from their own experience. Not a wow, but a lean. Get them leaning forward at a modest level, and then give the curve somewhere to go.
The Closing Problem
The mirror of the opening problem: the closing must be the highest point on the curve. Not just impressive — the culmination of a continuous rise. The climax lands differently when the audience arrives at it through a rising curve than when it arrives out of a plateau.
A climax after a plateau is impressive if the climax itself is impressive. A climax at the peak of a rising curve is cathartic — it releases the accumulated investment of the entire preceding experience. The difference in audience response is significant.
I’ve had performances where the closing effect was technically the same as in previous versions but landed completely differently — and the difference was usually the shape of the curve that led up to it. When the curve was rising, the climax was satisfying in a way that exceeded the technical merit of the effect. When the curve was flat, the climax was merely impressive.
What This Taught Me About Timing
The interest curve principle changed how I think about timing — not the micro-timing of individual effects, but the macro-timing of how a complete show breathes over time. The question is no longer “is each element as strong as possible?” but “is the trajectory of the whole rising?”
These can point in opposite directions. Sometimes the strongest element in isolation is not the right element in a particular position, because it creates a spike that produces a subsequent valley — a plateau below the spike’s level — rather than continuing the rise.
Building for the curve requires sacrificing local maximums for the sake of the global trajectory. This is harder than building for local maximums. It requires keeping the whole in mind while working on each part.
But the results are different. An audience that’s experienced a genuine rising curve — that’s arrived at the climax through continuously rising investment — has had a qualitatively different experience than an audience that’s experienced a series of peaks separated by flat connective tissue.
Interest occurs while it’s rising. Not while it’s high. Build for the rise.