There are many reasons as to which to use or a combination of them. Though the two most relevant are:

1. The Love and Glory gene being more emphasized can sometimes lead to a reduction in cost.
2. The Mony and Glory Gene can sometimes lead to a way of influencing the group's speed and direction.
 

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Each gene and its variants have specific outcomes/goals and thus are best used in certain combinations and types of systems.  

What Gene is Best Used In a What Situation

Malone, Thomas W. and Laubacher, Robert and Dellarocas, Chrysanthos N., Harnessing Crowds: Mapping the Genome of Collective Intelligence (February 3, 2009). MIT Sloan Research Paper No. 4732-09, Available at SSRN: https://ssrn.com/abstract=1381502 or http://dx.doi.org/10.2139/ssrn.1381502

Harnessing Crowds: Mapping the Genome of Collective Intelligence

1. Crowd- resources needed to do the activity are spread widely and/or not known in advance. It is also crucial that the main activity can be broken down in to smaller tasks 
2. Hierarchy- is used when the crowd conditions are not met. Though many systems use a mix of the two. Having the crowd create and a small group decide on final iteams.

Who: When to Use Crowd and Hierarchy Gene

Why: When to Use the Money, Love and Glory Gene

1. Collection- The conditions previously stated in the crowd node. The activity can be divided into small pieces that can be done independently of each other. 
2. Contest- The same conditions for collection gene though with only the want for a few solutions.
3. Collaboration- The activity can't be divided into small independently done pieces and you can manage the dependencies among said pieces
 

How- Create: When to Use Collection, Contest, and Collaboration

1.  Group Decisions- Conditions for crowd gene and when everyone in the group needs to follow the same decision.
2. Voting- When the crowd must be committed to the same decision.
3. Averaging- Conditions for voting variant and decisions are based on estimating a number.  The crowd must also have no systematic bias about the number.
4. Consensus- Conditions for voting and there is a reasonable amount of time permited to reach a consensus.
5. Prediction Market- Estimating a number is required and the crowd has some knowledge about the number that has been already estimated. The system wants/needs updated estimates and individuals varry on the amount of information they have or can obtain. 

How-Decide: When to Use The Group Decision Gene and Its Varients

1. Individual Decisions- The conditions for Crowd gene and the ability for the members to make their own decisions.
2. Market- When money is needed to motivate individuals to do the actitivy or provide effort and other resources. 
3. Social Network- When non-monetary motivations work just as well to get individuals to do the tasks and provide help. The opinion of others is used by individuals when making their decisions.  

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