Letter: Reflex reactions are even faster than you think

Share
Related Topics
JOHN McCRONE's 'Shots faster than the speed of thought' (Review, June 27) mentions Professor Ben Libet's claim that observing an event and reacting to it takes half a second. Yet your readers can prove it takes only one-fifth of a second.

Back in pre-Breathalyzer days, drivers checked their reflex speeds by getting someone to drop a pound note past their open forefinger and thumb. If you missed it three times in succession you were not fit to drive.

To test this, get someone to hold a 12-inch ruler vertically, with the bottom just level with your finger and thumb, held an inch apart. When they unexpectedly drop the ruler, snap finger and thumb together to catch it.

Many people can catch it after it has dropped 7 inches or less. The formula: S= 1/2 at2 (where S= distance in feet, a=acceleration due to gravity - 32ft per second - and t=time) shows that total elapsed time is not half a second in this case, but one-fifth of a second. If it were half a second, you'd miss the ruler as it would have travelled four feet]

Len Clarke

Uxbridge, Middlesex

React Now

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Project Coordinator

Competitive: The Green Recruitment Company: The Organisation: The Green Recrui...

Project Manager (HR)- Bristol - Upto £400 p/day

£350 - £400 per annum + competitive: Orgtel: Project Manager (specializing in ...

Embedded Linux Engineer

£40000 - £50000 per annum + competitive: Progressive Recruitment: Embedded Sof...

Senior Hardware Design Engineer - Broadcast

£50000 - £65000 per annum + Benefits: Progressive Recruitment: Working for a m...

Day In a Page

Read Next
The Lada became a symbol of Russia’s failure to keep up with Western economies  

Our sanctions will not cripple Russia. It is doing a lot of the dirty work itself

Hamish McRae
The Israeli ambassador to the US, Ron Dermer, has been dubbed ‘Bibi’s brain’  

Israel's propaganda machine is finally starting to misfire

Patrick Cockburn
Save the tiger: The animals bred for bones on China’s tiger farms

The animals bred for bones on China’s tiger farms

The big cats kept in captivity to perform for paying audiences and then, when dead, their bodies used to fortify wine
A former custard factory, a Midlands bog and a Leeds cemetery all included in top 50 hidden spots in the UK

A former custard factory, a Midlands bog and a Leeds cemetery

Introducing the top 50 hidden spots in Britain
Ebola epidemic: Plagued by fear

Ebola epidemic: Plagued by fear

How a disease that has claimed fewer than 2,000 victims in its history has earned a place in the darkest corner of the public's imagination
Chris Pratt: From 'Parks and Recreation' to 'Guardians of the Galaxy'

From 'Parks and Recreation' to 'Guardians of the Galaxy'

He was homeless in Hawaii when he got his big break. Now the comic actor Chris Pratt is Hollywood's new favourite action star
How live cinema screenings can boost arts audiences

How live cinema screenings can boost arts audiences

Broadcasting plays and exhibitions to cinemas is a sure-fire box office smash
Shipping container hotels: Pop-up hotels filling a niche

Pop-up hotels filling a niche

Spending the night in a shipping container doesn't sound appealing, but these mobile crash pads are popping up at the summer's biggest events
Native American headdresses are not fashion accessories

Feather dust-up

A Canadian festival has banned Native American headwear. Haven't we been here before?
Boris Johnson's war on diesel

Boris Johnson's war on diesel

11m cars here run on diesel. It's seen as a greener alternative to unleaded petrol. So why is London's mayor on a crusade against the black pump?
5 best waterproof cameras

Splash and flash: 5 best waterproof cameras

Don't let water stop you taking snaps with one of these machines that will take you from the sand to meters deep
Louis van Gaal interview: Manchester United manager discusses tactics and rebuilding after the David Moyes era

Louis van Gaal interview

Manchester United manager discusses tactics and rebuilding after the David Moyes era
Will Gore: The goodwill shown by fans towards Alastair Cook will evaporate rapidly if India win the series

Will Gore: Outside Edge

The goodwill shown by fans towards Alastair Cook will evaporate rapidly if India win the series
The children were playing in the street with toy guns. The air strikes were tragically real

The air strikes were tragically real

The children were playing in the street with toy guns
Boozy, ignorant, intolerant, but very polite – The British, as others see us

Britain as others see us

Boozy, ignorant, intolerant, but very polite
How did our legends really begin?

How did our legends really begin?

Applying the theory of evolution to the world's many mythologies
Watch out: Lambrusco is back on the menu

Lambrusco is back on the menu

Naff Seventies corner-shop staple is this year's Aperol Spritz