9

Several sources claim that left-handed people have shorter life-spans:

A left-handed academic from North Dakota has revealed that left-handers tend to die younger than right-handers. The "generally" right-handed population, he asserts, lasts on average to 68.7 years old. The generally left-handed live to just 65. Perplexingly, though, "extremely" left-handed people have an average death age of 67.4. And the ambidextrous fare best of all: their average age of death is just short of 70.

Source: The Guardian

Other examples: The Straight Dope, Godlike Productions, Fun Facts

I don't seem to understand why handedness would be a factor. There may be more mental friction in having to use right-handed items, but having any impact on your lifespan seems odd.

Oddthinking
  • 140,378
  • 46
  • 548
  • 638
Desolate Planet
  • 241
  • 1
  • 3
  • 8
  • One plausible mechanism (if that statement is true in the first place) is extra stress. – user5341 Oct 15 '11 at 00:15
  • Think injuries and accidents caused by (in the case of "generally left-handed people") using tools and whatnot as an inept right-handed person. The "extremely left-handed" would tend not to be "ineptly right-handed" circumstantially because of the degree of ineptitude; they'll go out of their way to use something designed for left-handed use or delegate the task if they can. There's also evidence suggesting that panic reactions while operating a vehicle tend to cause veering toward the stronger side; where one drives on the right, that means left-handers go into oncoming traffic. – Stan Rogers Oct 15 '11 at 18:07
  • @StanRogers - Thank goodness I'm in the UK since we drive on the left side :) – Desolate Planet Oct 16 '11 at 14:02
  • @Stan, do you have any links to that evidence - or even evidence that left-handers have more traffic accidents? – Oddthinking Oct 17 '11 at 00:49
  • @Oddthinking: It'll take a while to find; the studies (more than twenty years ago) weren't aimed at handedness, but left-vs-right-side driving (island-vs-mainland, essentially). The reaction was a "panic pull" -- the operator simultaneously pulls on the hand control (the steering wheel or handlebars) while straightening the legs -- and while the leg part is usually (but not always) directed at the brake, as one would expect with practice in normal driving, the pull isn't balanced. The lack of ready access to the studies (British and Australian) are the reason I commented rather than answered. – Stan Rogers Oct 17 '11 at 13:51

2 Answers2

10

Cross-sectional lifespan studies do show decreasing numbers of left-handers as the population ages, which does suggest that the sinister types are dying off at a faster rate than their dexterous companions. Assorted speculations exist as to why: the subtle effects on accident rates of living in a world structured on the assumption of right-handedness, the possible connection between perinatal stress and left-handedness, etc.

However, there is one significant confound with this finding: some cultures have a recently-abandoned prejudice against left-handedness. Due to this historical bias, many older individuals were raised in circumstances that actively encouraged left-handed individuals to adapt to right-handedness. The gradual dissipation of this trend (see Barsley M (1970) Left-handed man in a right-handed world. Pitman London. & Corballis MC (1993) The lopsided ape: Evolution of the generative mind. Oxford University Press, USA. p89. for discussion of the decline in handedness-related prejudice) could produce an increase in the number of detectable left-handers as time progresses without any need for differences in mortality.

See Coren S, Halpern DF (1991) Left-handedness: A marker for decreased survival fitness. Psychological bulletin 109:90-106 and Harris LJ (1993) Do left-handers die sooner than right-handers? Commentary on Coren and Halpern's (1991) "Left-handedness: A marker for decreased survival fitness". Psychological Bulletin 114:203-234 for arguments supporting both sides of this issue.

For a lengthy (and entertaining) discussion on the nature of handedness (and its possible connections to lateralization of brain function and the evolution of language) which includes a review of the evidence relating to left-handed survival rates, see Michael Corballis’ books “The Lopsided Ape” and “From Hand to Mouth”. Corballis MC (1980) Laterality and myth. American Psychologist 35:284 is worth a look as well.

Craig
  • 626
  • 6
  • 7
  • +1, but I would like to see another improvement. You claim that some cultures have a recently abandoned prejudice against left-handedness. Do any of your references support that statement? If so, could you please point that out. (An short excerpt would be even better!) – Oddthinking Nov 01 '11 at 02:24
  • Hmmn...Corballis makes the claim in a book that I can access from here (Corballis MC (2007) The dual-brain myth. In: Tall tales about the mind and brain: separating fact from fiction. Oxford University Press, USA. p 291.), but he doesn't actually provide any supporting evidence there himself. It's one of those "prove that water is wet" things; obviously true but hard to find a cite for, simply because it is so obvious. He might have a better-supported version of the same claim in The Lopsided Ape; I'll check my copy when I get home. – Craig Nov 01 '11 at 03:35
0

The first result in a google search found the following article http://news.bbc.co.uk/2/hi/health/102354.stm claiming the contrary.

The article is from 1998 and it cites "new" academic research.

Sindri Traustason
  • 462
  • 4
  • 7
  • Welcome to Skeptics! This is a good find, but quoting a reporter quoting a press-release isn't a great reference. You should follow up to find the abstract of the original paper in the Lancet, and provide some relevant quotes to (a) show it is relevant to the question and (b) protect us against link-rot. – Oddthinking Oct 17 '11 at 00:51
  • The original article is here http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)77690-X/fulltext but it's behind a paywall. – Sindri Traustason Oct 17 '11 at 14:33