The small-but-steady approach of birds, bees, and ants offers a better model for changing human behavior than the hop-to-it top-down model used by many companies and governments.

FORBES: The Birds and Bees of Sustainability

And shelling out for a snazzy rental car especially for a top-down model that will let you travel with the wind in your hair is one way to mix things up a bit and make the trip as fantastic as the destination.

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Besides, it turns out the human brain may not work on a top-down hierarchical model after all.

FORBES: The Birds and Bees of Sustainability

For decades researchers have tried replicating the top-down, hierarchical model of the human brain to create artificial intelligence in computers, without success.

FORBES: The Birds and Bees of Sustainability

Disillusioned with what he had seen of the traditional top-down, government-funded social services model, and now equipped with some knowledge of business, Lance decided on a capitalistic approach.

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Mr Cameron promised to end the "old-fashioned, top-down, take-what-you're-given" model of public services.

BBC: David Cameron: End state monopoly over public services

In future, Iran's subsidy reform may even be seen as a model for top-down social change, not unlike successful schemes pioneered by Mexico and Brazil.

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Especially in an era of gaming obsessed with the sort of free-to-play model that fuels both DOTA 2 and League of Legends, one would imagine a top-down RPG in this vein could do quite well.

FORBES: Move up http://i.forbesimg.com t Move down

But in an agent-based model you simply run a computer simulation to see what emerges, free from any top-down assumptions.

ECONOMIST: Economics focus