[evan_au (OP)]

The recent Naked SCientists story asked why are "Horses cannier than we first thought"?

It could be because they live in herds, and have to negotiate a complex pecking order (or perhaps biting and kicking order), every day.

So perhaps  it is important for a horse to recognise individuals and know how to interact appropriately with each?

https://www.thenakedscientists.com/articles/interviews/horses-cannier-we-first-thought
 

[alancalverd]

The experiment wasn't done with wild horses.

It's unlikely that a trained horse wouldn't recognise a penalty for noncompliance - training involves both reward and some form of penalty or withholding, and you'd expect that a horse that has been bred for working with humans would be almost as quick to learn the rules of a new game (including "wait for the signal") as a dog - essential if you are going to ride in traffic for the first time!

Horses certainly do recognise individual humans and other animals (including horses) and respond differently to those they have learned to like or avoid.

[Petrochemicals]

It sounds like horses are not willing to equate events as linked when they can be seperate independent of each other, presumably there will be no horse religion then, or maybe that is the next step in evolution, to start praying to the lightning and attacking each other because of it.