How Effective were Spears Against Cavalry?

[rrgg]

3. A line of horsemen vs a dense line of spearmen

Here it is the spearmen who have the upper hand. The horse will not (under most circumstances, with the training techniques, the equipment and stratagems used in those - and I think even today - times) blindly run into what it perceives as a wall. That means that the horses would actually not even wildly charge into a line of swordsmen. One, two, maybe three would but not the whole line. So there goes the main threat. Spears though give an edge, since they can hit against horsemen approaching the line, pushing with a trotting movement against the men, jabbing with spears or those galloping along it. What a cavalry charge, a massive line of iron-clad horses thundering towards the infantry could achieve was that the line could not withstand the psychological pressure and left their lines degenerating into a disordered mass, taking us back to situation Nr 2.

Of course the ability of the horse to blindly charge into a wall (this is how the horse perceives a dense shieldwall) and its tactical use on the battlefield are an issue many of us have debated on for a long time and with a lot of arguments, but I think that consensus is that this was not the role of cavalry. After all, in order for such a tactic to be implemented one such horse with an equally resolute rider are not enough... you need hundreds of both of them.

With number 3 is that assuming a large number of infantry against a smaller number of horsemen or a large number of infantry against an equal number of horsemen? How much damage would a horse that did keep charging cause?


Slightly related question, in large numbers would a 'stampede mentality' make horses more likely to charge into danger?