In general, they'd be waiting for the signal from their commander or leader to move forward and replace those in the front, or ready to pour in through the middle, or flank from the sides - it depends largely on the strategy employed by the commander. They could also be cheering for their side or attempting to demoralise the opposing army, or any other number of things. The scenario of them asking "What's happening with our comrades in front?" or related questions didn't occur so much as due to the fact that these soldiers had some form of training, and with it, discipline - whilst their morale may have been less than, say, veterans, they definitely didn't openly wander around and ask these questions.

I'm not too familiar with other cultures, but in Greek and Hellenic warfare, the phalanx had a very common way of organizing itself: The front ranks were often the younger and fitter men, and those best able to fight without becoming exhausted or terrified. The rear ranks were often older veterans, men who had lived through enough that they weren't seen as needing to constantly risk their lives but still able to fight if need be. The middle ranks would generally have been the most green of soldiers - the most undependable and/or youngest, to be held in place by the men in their prime who were at the front, and the grizzled veterans at the back. This was not a universal system, just broadly followed. The men in the ranks before the frontmost would generally have been simply waiting to move forward if the man in front of them fell or was killed - NOT pushing, as there is very little evidence to suggest hoplites pushed each other in combat like a rugby scrum.

For more information or the Greek/Hellenic/Roman world, or if you want to just ask this question there, visit Romanarmytalk.com - it's a fantastic forum filled with mostly historians.