Unlike genetic evolution, memetic evolution can show both Darwinian and Lamarckian traits. This idea has been related to memetics or the memetic concept of culture. Memetic algorithms represent one of the recent growing areas of research in evolutionary computation. The practice of using memes to market products or services is known as memetic marketing. Researchers have used memetic algorithms to tackle many classical NP problems. Furthermore, many people term their memetic techniques as "genetic algorithms". For example, it can also be applied to scientific discovery, memetic evolution, or genetic programming. Memetic algorithms have been successfully applied to a multitude of real-world problems. Some variations on the memetic algorithm involve alternating between selection at different levels. In Multi-meme MA, the memetic material is encoded as part of the genotype. A metaphor or the idea of memetic engineering are, thus, metamemes. Memetic engineering as a social science lends examples of itself in multiple areas and disciplines. Occasionally their civilization collapses, due to memetic plagues. In the MoS universe, mad scientists suffer from SRMD, Science Related Memetic Disorder. Frequently used slang also have become conventionalised into memetic "unit[s] of cultural information".