Memetic Selection

How behavior and ideas spread and evolve.

Meme theory is a profoundly alien, and profoundly useful, way of thinking about human behavior. It likens both actions and ideas to the genes that make up DNA, which makes complex behaviors and belief systems a lot like living species. They all reproduce, change, and evolve through a process of selection. To understand memetic selection, you must first understand natural selection.

Susan Blackmore paraphrased Darwin's thoughts on the matter...

"He reasoned that if living creatures vary (as they certainly do) and if, due to their geometric increase in numbers, there is at certain times a struggle for life (which cannot be disputed), then it would be most extraordinary if there were not some variation that was useful to a creature's welfare. The individuals with these characteristics will then have the best chance of being 'preserved in the struggle for life' and will produce offspring with the same characteristics. This was the principle he called 'natural selection'"[1]

In "The Selfish Gene," Richard Dawkins decoupled natural selection from genetics.[2] He realized that any group whose members...

  1. differ from each other on certain traits,
  2. pass those traits on to their descendants, and
  3. compete for the chance to reproduce,

... logically must evolve over time. Anything that meets these three criteria can be considered a replicator, not just genes and DNA.

To illustrate this point, he described human behaviors as replicators. They are certainly variable, both between people and over time. They reproduce through imitation and each person imitates some aspects of a behavior better than others. They compete for survival by virtue of the fact that no one could possibly demonstrate every behavior in their repertoire to every person they encounter. Some behaviors must be displayed, and therefore imitated, more often than others. Dawkins coined the term "meme" to describe this kind of replicator, a "mental gene."

As an example, let's say you learn a song by singing along with the radio. The song can be considered a meme because you're reproducing it. Of course, you don't get all the lyrics right and you know the chorus better than any of the verses, so the song you sing isn't exactly the same as the one on the radio. Then, you sing your version of the song around your little sister, who imitates you all the time. Her vocabulary is limited, so she changes even more of the words and forgets most of the verses. The song she sings is now even more different from the one on the radio.

Now, keep in mind that you sing along with more than one song. Some are easier to remember than others. Your little sister learns the easy songs faster both because they're easy and because she hears you sing them more often than the difficult songs. If we compare the radio's playlist to your little sister's daily recitals, we'd find significant differences. The difficult songs will have died out and the easy songs would have evolved.

That's memetic selection.

Memetic Selection Pressures

There are three ways that a meme can improve its fitness for survival. Each has certain advantages and disadvantages, and each relates to a different list of selection pressures, both social and technological.


... is how often a behavior occurs. Each occurrence is another chance to be imitated by others. In genetic terms, it's how often an organism reproduces. Elephants are pregnant for 22 months, which means they are able to reproduce less often than human beings. Humans have greater fecundity than elephants.

Behavioral psychologists have understood memetic fecundity for decades. They call it "conditioning;" most people call it "learning." Simply put, behaviors that are rewarded occur more often than behaviors that are punished. Sometimes, the reward or punishment comes from the environment. People sniff flowers more often than they sniff gym socks, because one smells good and the other makes them wish their noses were disposable.

The really interesting things happen when memes reward or punish each other. Making something illegal, or condemning it as amoral, imposes selection pressure against the unwanted meme, making it less fecund. Websites that highlight their "best" content or contributors increase the visbility of their memes, creating more opportunities for them to reproduce.


... is how precisely a behavior can be imitated. Simple behaviors are easy to reproduce, but errors start to creep in as behavior gets more complex. Maybe it's hard to do right, or maybe it's just hard to remember, but people tend to improvise when they don't know for sure.

High and low fidelity both have their drawbacks. Memes that change too much each time they're imitated end up spawning countless mutations until the original is lost to history. Memes that change too little won't have the variability they need to adapt to new conditions.

Consequently, memes that accurately depict complex topics are always at a memetic disadvantage. Compare any scientific theory to its depiction in popular culture. You'll find that much of the complexity gets lost as the theory is put into progressively simpler terms. These watered-down versions are less accurate models of reality, but they're easier to remember, so they spread farther and faster. In other words, the truth is always at a memetic disadvantage.


.. is how long a meme remains in an imitable form. The longer it persists, the more chances it has to replicate. A spoken word drifts away on the wind, while a written word can remain unchanged for centuries. Text also eases the burden on memory, since it can be referred back to later, which improves the fidelity of complex memes.

The last two generations of communication technology provide interesting case studies. Broadcast radio and television dramatically increased the fecundity of the memes they carried, but they decreased longevity relative to print. This put complex memes at a severe disadvantage. Mass media culture is extremely widespread, but it favors sound bites over discourse.

The internet combines the persistence of print with the reach of broadcast. This should ease the bias against complex memes, though they will still be at some disadvantage. Higher bandwidth makes room for more memes, even if they're reaching smaller audiences. Over time, these forces will increase diversity in the marketplace of ideas, which makes our cultural memepool more adaptable. Hurray for the internet.


  1. Blackmore, S. (1999). The Meme Machine. Oxford University Press.
  2. Dawkins, R. (1979). The Selfish Gene. Oxford University Press.