**Subject: Imminent extinction of paper "luck chain letters."**

**I predict that the familiar "prayer" or "good luck"
type chain**

**letters will totally disappear from the US mail by the year**

**2000. To argue this some much needed terminology (in**

**caps) will be introduced - please gripe about any you don't**

**like. Let's call these letters LUCK CHAIN LETTERS**

**(LCL). In contrast, a MONEY CHAIN LETTER (MCL)**

**asks that money be sent to one or more prior recipients.**

**Both have PAPER and CYBER versions. Digitization is**

**not a new phenomenon; MCLs circulated via telegraph sixty**

**years ago. Some population mathematics will also be**

**described which, though not essential to follow the**

**argument, has helped me to see how critical small factors**

**are for the survival of chain letters and their variants. The**

**key fact here is that kids are getting E-mail before they get**

**any snail mail. Reasoning:**

**(I) Population dynamics, exponential growth and decay.**

**If m letters in hand result in n letters in new hands, define**

**the GROWTH FACTOR as f=n/m. Starting with m letters,**

**after t generations there will be P=m*(f^t) letters. The**

**familiar "exponential growth constant" is the natural**

**logarithm ln f. GENERATION TIME is the average time**

**to go from one hand to another - about one week for paper**

**LCLs ( the four days DEADLINE plus three days in**

**transit). For f>1, doubling of a population occurs in d=ln2 /**

**ln f generations. Thus if 20 copies of a LCL produce on**

**average 22 copies, then f=22/20=1.1 and d is about 7.3**

**generations or two months. At this rate of doubling, U.S.**

**saturation (100,000,000 copies) would occur in 7.3 years.**

**If f=18/20=0.9 the population is declining, halving every**

**two months.**

**(II) Long term survival, feedback control.**

**A constant growth factor (exponential growth) is a**

**reasonable assumption for a replicator in a large**

**homogeneous population. However LCLs have neither**

**disappeared nor covered the earth. Thus the long term**

**growth factor is extremely close to f=1; phases of**

**exponential growth / decay being episodic. This survival**

**implies feedback control on population. Call a social**

**replicator DECREMENTAL if a person is less likely to**

**reproduce it on multiple exposure. Thus jokes are highly**

**decremental. Chain letters are also decremental (noted by**

**Wickets, also Goodenough and Dawkins). Some polling on**

**this should be done, but it seems clear for the LCLs at least.**

**Thus exponential growth is checked by saturation of the**

**available human population. And sustained decay produces**

**a large new crop of potential first time recipients, thus**

**increasing the growth factor. Such population dynamics**

**can be modeled by the "logistic" curve.**

**(III) Cyber versions, youth access.**

**Cyber LCLs are widespread on the Internet, and within**

**private On-line services. What is important here is not how**

**many have been sent, but the likelihood of receiving one. It**

**seems we all do after a few months. And this must apply to**

**the hundreds of thousands of youth with access. I believe a**

**sample will show that most who are sending cyber LCLs**

**(like the SPEAR CHUCKER letter that now predominates)**

**are dependents. Thus they have had little chance to receive**

**a paper version, since those go to a mailing address, or are**

**distributed at places of employment (in work mail boxes, or**

**left on desks). Consequently paper versions are being**

**deprived of a significant proportion of first time recipients,**

**and it will only get worse as millions more get on-line. It**

**will do no good if a more replicative paper version appears**

**- it will just be put on the net (e.g. to save on distribution**

**costs) and again the paper medium is deprived of first crack**

**at virgin recipients. For these reasons I believe paper luck**

**chain letters are already in a rapid decline in the U.S., and**

**will completely disappear in a few more years.**

**Dan VanArsdale, 6/7/95, barnowl@rain.org**

Posted to the CU Boulder folklore list on June 7, 1995 by DWV (now at barnowl@silcom.com).

e1995-06_post_extinction.htm

Chain Letter Evolution (a
history of paper chain letters).