A x B x C x D = belief
Heylighen (1998) also sets out a way of calculating a success factor for memes. This, as you will recall from our discussion on zombies, is the number of memes in one generation divided by that in the preceding generation. If the factor is greater than one, the meme will spread.
If we multiply the success of each of the four stages we discussed above (assimilation, retention, expression and transmission), we have a simple equation describing the spread of the meme:
Success Factor =
Probability of a meme being accepted (0 to 100%) x
Probability of the meme being retained (0 to 100%) x
The number of times the meme is expressed (0 to ∞) x
The number of times it reaches a new potential host (0 to ∞)
The first pair of elements describe the chances (from 0 to 100%) of the meme being noticed, understood, assessed as true, and stored as being useful. Here, ‘retained’ means ‘retained long enough to be transmitted’, just as ‘survival’ for an organism only matters in evolutionary terms up to the point where it reproduces.
The second pair of elements is the number of times the meme gets passed on – this product can be a low number if the meme is expressed infrequently and rarely transmitted, or expressed often and transmitted widely (such as a television advert).
We can also think about the way that memes compete, which we described in the page on the growth of complex systems as a Markov Chain, by introducing a fifth term:
Success Factor =
(Probability of a meme being accepted (0 to 100%) x
Probability of the meme being retained (0 to 100%) x
The number of times the meme is expressed (0 to ∞) x
The number of times it reaches a new potential host (0 to ∞) ) x
(1-Probability of defection (0 to 100%))
Example: a meme has a 20% chance of been accepted and a 50% chance of being retained.The new host tells one person about it (on average) every hour, so the success factor (ignoring defection) is 20%x10%x24x1 = 2.4 per day. If only 20% of those reject the meme subsequently then the overall success factor is 1.92 per day.
Memes rarely make it all the way through this lifecycle sufficiently often to guarantee growth and fight off competitors. If you are reading this, then the memes hosted on this website have at least been successfully transmitted. Hopefully, some of you will assimilate them and retransmit when you tell your friends and colleagues how their lives will be enhanced if they infect themselves the way you have.