The concept of linkage applies well in memetics too - leading to the idea of memetic linkage - which is the idea that nearby memes are more likely to be inherited together as a result of their close proximity.
To give some examples:
Adjacent sentences in documents tend to become linked together - and quotations may take adjacent sentences with them. Much the same thing happens with audio and video. Images may juxtapose unrelated subjects - which then become linked together.
For example, consider the girl standing in front of the CN tower. Or consider the aeroplane and the tourist in the images on the right. These days, the girl is often found with the tower, and the plane is often found with the tourist. Proximity-based linkage based on common descent is the primary reason for this.
Edward Burnett Tylor's adhesionsEdward Burnett Tylor laid the groundwork for the idea of memetic linkage in his concept of an `adhesion'.
Tylor was interested in cultural traits that appeared together, whether one trait caused the other, whether they were transmitted together, or what was happening.
Tylor presented his work on adhesions in a paper entitled:
“On a Method of Investigating the Development of Institutions; Applied to the Laws of Marriage and Descent,” which was published in volume XXVIII (1889) of the Anthropological Institute's Journal.
Tylor’s paper presented a method of “social arithmetic,” or statistical analysis of the presence of and “adhesions” between "traits". "Adhesions" broadly corresponded to correlations while the "traits" he considered were customs and institutions. He sought to compare traits with "adhesions" - to find those that seemed to occur together more frequently than the laws of chance would suggest.
Linkage-driven migrationAn idea associated with the idea of genetic linkage is that alleles that have some kind of functional dependence on each other tend to migrate towards each other, so that linkage effects are increased, and the chances of them being divided from one another are smaller.
There are also other reasons that cause related ideas to clump together. That may mean that this effect may not be trivial to tease out experimentally.
Quantifying linkageIn genetics linkage can be quantified by measuring how far the linked alleles are from one another on a chromosome - or by looking at descendants and calculating the chances that the alleles are inherited together.
In memetics, the second option is still possible - memes frequencies can be tracked such as gene frequencies can - but a predictive theory based on the original heritable information itself is not so easy. Memes do not line up neatly in a one-dimensional space where distances from one another can be calculated easily. In podcasts and videos, temporal linkage may well be more significant than spatial linkage is. The linkage of a word to its neighbours depends little on whether the word is on one edge of the page. The linkage-distance between two memes is a more ambiguous concept than the linkage-distance between two genes. Instead you typically have to clearly specify what metric you are measuring memetic linkage with.
Criticism from Richard DawkinsRichard Dawkins apparently denied the existence of "memetic linkage" in his 2005 book "The God Delusion". He said:
We doctors call that kind of linkage linkage, and I shall say no more about it because memes don't have chromosomes, alleles or sexual recombination.However, he denied the existence of sexual memetic recombiantion in the same sentence - and that is surely an even more obvious concept.
Memetic linkage doesn't depend on memes being strung together in linear strings. The concept may be interpreted more loosely as an association - and then it becomes pretty clear that the idea does transfer across into the cultural realm. There is literature on "cultural linkage disequilibrium" - from Liane Gabora (1996). Memetic linkage disequilibrium is probably a better term, though.
Memetic hitchhikingMemetic linkage is an important concept in helping to explain how memetic hitchhiking works.