[somstuff (OP)]

Is it possible for a for another animal or organism w/ brain to perceive events faster or slower than humans do?

By this I mean, do you think it's possible for an animal to see an event in fast motion (imagine watching a moving in fast-forward), while the actual "time" that passed is the same? The animal's own actions would also be in fast-forward, as it sees them. "Time" would seem to pass by faster to them than it does to us. Or maybe, with more mental capacity, an animal would see actions in slow motion (compared to us), and thus would have more time to evaluate them, yet its own actions would be slow too.

Let me know if this makes no sense at all, it's kind of hard to explain/grasp.

[CliffordK]

Let me take an early stab at this...

One's reaction time would be largely dependent on the number of synapses.

So...  the fewer synapses one has in a pathway, the quicker one could do something like reacting to movement.

And, the less thoroughly you process the information, the quicker. 

There may be advantages of having a "Bird Brain" after all 

[SteveFish]

In general myelinated neurons in mammals have similar conduction speeds, although there are some specializations for handling species specific tasks (e.g. giant squid axon, although not a mammal). Similarly, interneuron processing, without action potentials, have a similar speed of conduction between critters that depends only upon neuron size. I think that in terms of neural processing, the smaller the brain the faster the processing. However, smaller brains can't process as complex information, so there is a crossover point between them. For example, in comparing a human and a mouse in terms of the ability to detect, and react to, a rapidly appearing (think pop up) threat, the mouse would have an advantage. For this scenario, check out desert kangaroo rats (actually mice) that can bounce up to avoid a rapidly approaching threat (owl). On the other hand, a human might not even be subject to predation because he could interpret the situation before the crisis, but would be slower if surprised. So the answer is yes, but only for very simple situations.

It is interesting that Clifford brought up birds. Many predatory birds have vision much more acute (in the daytime) than most other creatures. Some raptors even have telescopic vision. Such birds could react much quicker to threats, or opportunities, just because of their optics. This fact alone should illustrate the complexity of the question.

One further fun point. Consider a large dinosaur. If you could sneak out and whack its tail with an axe the time for conduction of this stimulus clear up to the brain would allow you the time to hide before the dino could turn its head to see you.

[CliffordK]

I found this...

A human has a reaction time of about .25 seconds
A common housefly has a reaction time of about .02 seconds (about 12x as fast).

The difference being due to simple processing and short distances in the brain.

http://www.thetech.org/exhibits/online/robotzoo/guide/fly_reaction.html

[somstuff (OP)]

I'm not really talking about reaction time though. I mean like if a human looked through a fly's eyes, the movements it sees would be slower than we see them, as if it was in slow motion. You can have a fast reaction time, but things would still appear to be the same speed, you just become aware of them more quickly. And all humans have the same perception of speed, but they can have different reaction times, however slight.

[CliffordK]

Certainly there are different aspects of perception and speed.

And, yes, there is more than just reaction time.

But, consider swatting the housefly with your hand...  something that is difficult to do.

The fly looks up...  as it sees your hand already in motion...  it has a few milliseconds to decide that it is time to scoot.

Your hand slaps on the table as fast as you can do it...  and you sit there dismayed that the fly has already seen it coming and headed off.

As far as reaction times...  there is some variability.
But, if I say blink a light on the screen and ask you to hit the space bar...  Even though you are all primed and ready to go...  it will take you longer to hit the space bar than it would take the fly to see your hand coming down towards them and to fly away.

The reason is shorter circuitry in the brain.

Now, you might also argue that the fly's actions are more of a reflex...  like the patellar tendon reflex, which is much faster than the reaction to a blinking light on the computer screen.  And, being a reflex, they find themselves airborne before they even realize what is happening (if a fly can have any self-perception).

Now...
Chowing down on a chunk of meat...  is there any difference in the perception of time passing between the fly and the human?

Remember, of course, that our units of time, second, minute, hour, are all quite arbitrary.  Units such as a day and year are based on local phenomena on the earth that would be different on different planets in the solar system.  A Month, is only a crude approximation of a lunar orbit, and rather than being based on the actual lunar orbit, is adjusted to match other more convenient time periods.