The second stage of memetic replication is the retention of the meme in memory. By definition, memes must remain some time in memory, otherwise they cannot be called memes. The longer the meme stays, the more opportunities it will have to spread further by infecting other hosts. This is Dawkins's (1976) longevity
characteristic for replicators.
Just like assimilation, retention: is characterized by strong selection, which few memes will survive. Indeed, most of the things we hear, see or understand during the day are not stored in memory for longer than a few hours. Although you may have very clearly assimilated the news that the progressive liberal party won the Swaziland elections with 54% of the votes, you are unlikely to remember anything of this a week later--unless you live in Swaziland, perhaps. Retention will depend on how important the idea is to you, and how often it is repeated, either by recurrent perception or by internal rehearsal. All learning paradigms agree that experiences are encoded more strongly into memory by frequent reinforcement. (Heylighen, Francis, 2001)