It has come to our attention that some have claimed that Pres. Donald J. Trump has increasingly been falling asleep in meetings. Some have even suggested this is a result of insufficient sleep at night or even of declining health. Recognizing that such speculation is not helpful to the public discourse, we decided to investigate. We hope you will find the strategy useful; it involved asking some questions for artificial inteligence sites that our reporters deemed applicable.

How long does a rapid eye blink last?

A rapid eye blink usually lasts about 0.1 to 0.4 seconds, with many sources describing the average blink as roughly 100 milliseconds.

For context, that means a blink is fast enough to happen in a fraction of a second, but the exact duration varies by person and by whether the blink is voluntary or reflexive.

Use the average number of times a peson blinks per minute to estimate the probability that a photograph will show a person with eyes closed.

One can estimate this probability using the blink rate and blink duration.

Key numbers:

Parameter Value
Average blinks per minute 15–20 times
Average blink duration 0.1–0.4 seconds (100–400 ms)
Typical camera shutter speed 1/100–1/250 second (0.004–0.01 s)

Calculation:

Using the average:

Blinks per minute = 17.5 (midpoint of 15–20)

Blink duration = 0.25 seconds (250 ms, midpoint of 100–400 ms)

The probability that a person has eyes closed at any random moment is:

P(eyes closed) = blink rate × blink duration ÷ 60 seconds

P(eyes closed) = 60 seconds blink rate × blink duration

P = (17.5 × 0.25 ÷ 60) = (4.375 ÷ 60) = approx 0.073

Result: ~7.3% probability (about 1 in 14)

Using research-backed assumptions:

The Ig Nobel Prize research by Barnes and Svenson assumed:

Blink frequency when being photographed: 10 times/minute (people try not to blink)

Blink duration: 0.25 seconds

P = (10 × 0.25) ÷ 60 = 2.5 ÷ 60 ≈ 0.042

Result: ~4.2% probability (about 1 in 24)

This matches their finding that the probability of not blinking is ~96% (23/24). So the probability of a photograph showing a person with eyes closed is approximately 4–7%, depending on whether you assume normal blinking or photograph-conscious reduced blinking.

The exposure time (shutter speed) of a digital SLR in burst mode is not fixed by burst mode itself—it's whatever shutter speed you've set for your shot. Burst mode only controls how many frames per second the camera can take while you hold the shutter button.

However, there are important practical constraints:
Key facts about burst mode exposure:
Aspect Detail
Shutter speed Set by you (e.g., 1/500s, 1/1000s)
Typical burst rate 3–8 frames per second for most DSLRs
High-end DSLRs Up to 14 fps (Canon EOS-1D X Mark II)
Minimum shutter speed constraint Some cameras limit burst mode at shutter speeds 4 seconds or slower (no shot limit then)
Practical minimum To achieve high fps, you typically need fast shutter speeds (1/250s or faster)
Why shutter speed matters in burst mode:
The camera's burst rate depends on how quickly the shutter can open and close

Fast shutter speeds (1/500s–1/4000s) enable maximum frames per second

Slow shutter speeds (1 second or longer) drastically reduce burst rate because the shutter stays open longer

The camera's buffer also limits how many consecutive shots before slowing down

So if you're asking "how long is each exposure?"—it's whatever shutter speed you set, not a fixed burst mode value. If you're asking "how fast can the camera shoot?"—that's typically 3–8 fps for most DSLRs.

That being the case, what is the cumulative probability that a person whose eyes were closed for 1, 10, and 30 seconds was blinking at such a rapid rate that his eyes appeared closed the whole time?

This question asks about an impossible scenario — the probability is essentially zero.

Why this is (nearly) impossible:

Duration; What's required; Physiological reality

1 second: Eyes closed continuously for 1 second; Even the longest normal blink is only 0.1–0.4 seconds

10 seconds: Eyes closed continuously for 10 seconds; Maximum blink is 400 ms — you'd need 25+ consecutive blinks with zero gap

30 seconds: Eyes closed continuously for 30 seconds; This would require 75+ consecutive blinks with no reopening

Key facts:

Maximum blink duration: Even the longest blink is only 400 milliseconds (0.4 seconds)

Blink gap is unavoidable: Between blinks, eyes must reopen. Even with "rapid blinking," there's a recovery period — you cannot blink so fast that eyes stay closed continuously

Sustained eye closure is NOT blinking: Keeping eyes closed for 1+ seconds is called maintained eye closure or sustained blinking (which requires deliberate effort, not rapid reflexive blinking)

Normal blink rate ceiling: Even under stress/rapid blinking, the rate is maybe 2–5 blinks/second maximum, but each blink still only lasts 0.1–0.4 seconds

The mathematical answer:

For eyes to appear closed for 1 second continuously through rapid blinking:

You'd need blinks with zero gap between them

Each blink is ≤0.4 seconds

Even at 5 blinks/second, gaps exist between blinks

P(continuous closure via blinking) ≈ 0
P(continuous closure via blinking)≈0

The probability is effectively zero because rapid blinking cannot produce continuous eye closure — blinking inherently means repeatedly closing and opening, not staying closed.

If someone's eyes were closed for 1, 10, or 30 seconds, they were not blinking rapidly — they were either

• Voluntarily holding eyes shut
  
• Having a medical episode (e.g., seizure, fainting)
  
• Sleeping

It appears that Claude, Perplexity and the American people agree.