This is interesting recreation of Hoplite combat using agent-based modeling.  An important rule to remember is that the individual is the supreme decision maker, yet this does not rule out complex patterns of behavior.

Hoplites fought in massed formation, but the formation does not act like a unitary mind – even with a great general. It displays results that stem from a large number of individuals.

Rob McDermott:

The view of battle is from directly overhead, looking down on individual hoplites who interact while acting autonomously in accordance with five simple rules and in response to their own immediate situation. Each hoplite knows nothing about the wider progress of the battle, and there is no centralized organization. Everything that happens in the battle is entirely attributable to the interaction of the hoplites. The battle demonstrates that the sort of complex behaviour that we associate with hoplite battle – such as low casualties, a drift to the right, each side winning on their right, localized advantage held by each army at different parts of the line, the collapse, and a relationship between cohesion and survival – can be explained in terms of the interaction of individual hoplites. It also shows that the othismos – which is traditionally thought of as massed shoving – can be explained as a consequence of a large number of individual hoplites striving to gain forward ground.

There is a video demonstration of the experiment.

This produces historically accurate casualty rates (5-14%), the drift to the right, the “shoving” forward of men in the rear, and the way hoplite formations tend to win on the right flank and lose on the left flank.

Men on the Left rout under pressure causing the entire line to collapse. Cohesion increases survival rates and the ability to win. Good generals placed their best troops on the Left, or placed reserves nearby to prevent this collapse. The best generals focused on training individuals to fight well instead of assuming he had god-like powers to direct this battle once it was underway.

The hoplite is seen as a “collective” military unit, yet it all comes down to the power of the individual. Better trained, more disciplined individuals with higher morale will defeat lower-quality individuals in battle. Perhaps this is the key to understanding why free men fought the best even in massed formation.