Zombies have a keen sense of smell.

[lozz08 0]

The pathogen responsible for the outbreak causes certain neural areas to take precedence over others. Areas dedicated to cognitive reasoning shrink and areas dedicated to senses like smell increase in size.

This is possible and in fact occurs in our brains every day. Neuro-plasticity.

Perhaps it should be considered that zombies have a powerful sense of smell. Larger groups of players could increase the awareness of zombies to a state that makes them easier to aggro.

It could add gameplay mechanics such as using meat to distract zombies. (Speaking of which, wouldn't it be cool if you could feed zombies like ducks, throwing pieces of meat at them and watching them fight over it :D)

[JamesButlin 108]

I like the suggestion about using meat as a distraction, that would be quite cool! Imagine if smell attracted zombies towards you (depending on wind) without aggroing them? If they were slowly driven to walking towards you because they caught your scent from far away :P Would be better than just randomly wandering around all the time!