Tuesday 14 September 2010

Seven year units

Ten Commandments by Leo Szilard, c1940, Number nine:

"Do your work for six years; but in the seventh, go into solitude or among strangers, so that the memory of your friends does not prevent you from being what you have become."


Because of astronomy and the decimal system, human life tends to be measured either in years or decades. Yet, a year seems too short to measure the trends and transitions of an individual life or the life of a human institution; while a decade seems too long.

But the half-decade, which is often used in politics and by state bureaucracies – e.g., the five year plan, five yearly evaluations of organizations, or five year grants for individual scientists or programs for funding advanced research – seems too short.

I would suggest that traditional wisdom and empirical observation unite in recommending a 7 year unit for measuring human life; and that seven years should become the standard unit for tracking social trends, measuring individual attainment, and for strategic planning and support.


There are precedents for using a seven year unit. These range from the jokey ‘seven year itch’ (after which married men supposedly want to become unfaithful to their wives) to a notorious saying attributed to the Jesuits: ‘Give me the child until he is seven, and I will show you the man’.

This led to a famous and very popular UK documentary television series called ‘Seven up’ in which director Michael Apted interviewed a cohort of seven year old children in 1964 and has followed them at seven year intervals ever since.

Most viewers of the program would agree that the time frame seems just about right for tracking the lives of this symbolic British sample. Perhaps, seven years corresponds to some currently obscure human psychological or developmental cycle?


Naturally, seven years is inexact – even Leo Szilard’s own life did not fall precisely into seven year units of professional activity. Yet seven seems near-enough as an analytic division, and nearer than the rival decimal-related measures. Even when people talk of cultural decades (e.g., the ‘naughty nineties’ or ‘roaring twenties’ in England) it can usually be found that there is a better-fit for seven years. The most famous recent decade – ‘the sixties’ actually falls more neatly into the optimistic technocratic early ‘swinging’ sixties up to about 1968; then a late-sixties/early seventies characterized by hippies and a more pessimistic counter-culture of psychoactive drugs and utopian protest.


In science, likewise, seven year units work well. Seven years is approximately the time spent at high school, and then the time taken for a traditional basic scientific training (e.g., the first degree and doctorate). The early post-doctoral period, building the knowledge to become an expert specialist, is also about seven years. After this, matters are less clear, and it would be interesting to perform empirical studies measuring career increments and professional transitions on a random group of scientists.


At any rate, there is already enough anecdotal evidence to support the idea that we should at least reconsider the reflex but un-thinking use of five year plans and evaluations, and the analysis of social, professional and personal trends by whole decade units.

A new – and previously unconsidered – field of research beckons.

(Edited from http://medicalhypotheses.blogspot.com/2007/07/scientific-life-seven-year-units.html)


dearieme said...

The common estimate for the time taken to get over a bereavement sufficiently to get on with life again is 14 months.

Anonymous said...

One is a "teenager" from the 13th to the 20th birthday -- seven years.

Anonymous said...

Hippocrates divided human life into seven periods based on 7-year units:

paidion (0-7 years old)
pais (8-14)
meirakion (15-21)
neaniskos (22-28)
aner (29-49)
presbytes (50-56)
geron (57-)

Bruce Charlton said...

@wmjas - thanks for this - never seen it before.

Numerology Journal said...

There are two other options with spiritual significance and a history in the esoteric traditions of the West.

One is the Pythagorean system, kept alive largely in the esoteric field of numerology, which uses cycles of 1 to 9.

The other is the Chaldean system, which uses cycles of 1 to 8. The number 9 is left out in the Chaldean system as it is considered the name of God, and thus unspeakable and unknowable by man.

As a symbol of luck, the number 7 has had a strong traditional association for Europeans. 7 has a more mystical connotation than the 8, which has traditionally been more popular in the East for its associations with material abundance.

Cycles of 7, 8, or 9: Each is an improvement over the 10, if rich associations and a relationship to more meaningful cycles is desired.

However, the 10 is appropriate for our binary age, as it composed of a 1 and a 0. After all, we do seem to be building, and becoming, machines.

The Plague Doctor said...


Have you looked into the concept of "shmittah", the ancient Judaical concept of a 7 year cycle at the end of which all debts are to be cancelled.

Some believe this is also when the US economy will collapse, as the US economy appears to collapse approximately every 7 years. However, I believe this to be a coincidence: rather, I think that the Federal Reserve, has each time tried to postpone the collapse (raising of interest rates) until the respective next presidential election (in the recent past the US has had a change of president every 8 years) so that the next president gets the hot potato.

Bruce Charlton said...

@PD - No, I didn't know abut that. Maybe Szilard did, however - being Jewish.

The Plague Doctor said...

I also find it interesting that both Andrew Wiles and Grigori Perelman [subtitled] each took 7 years working in seclusion to prove Fermat's Last Theorem and the Poincare Theorem respectively.

By the way, I came across your book on the corruption of science due to a recommendation by Sister Y and it has quickly become one of my favourite books of all time!

The Plague Doctor said...

Also interesting: you mentioned Margie Profet who had disappeared for 7 years (2005-2012).

Bruce Charlton said...

@PD - Yes,it seems like a silly idea at first - but there is something in it!

The Plague Doctor said...

The body completely replaces itself every 7 years (except for bones and long-lived nerve cells):

Does your body really replace itself every seven years?

Every Seven Years You Change