As I pointed out in my post, the longer you use Android the further off your perception becomes. To get an accurate measurement I had to play with my Nexus S and an iPhone side-by-side, doing identical movements, and had a ruler and zoomed camera pointed at them both. After removing my mental bias from having become conditioned to that "pull" latency, the difference was pretty obvious.

I was also in the same boat about believing it was just a few millimeters, until I actually went ahead and measured it. My mind was thinking a millimeter was larger than it actually is.

I just tested again, with measuring tape, and I can get the lock screen sliding in less than a milimeter. What device do you have?

Try it with a scrolling list. The unlock button activates as soon as you press down on it. I was having the same results and didn't really believe his claim until I tried it elsewhere in the OS. 0.5 cm seems about right.

Anyone here familiar with Android's source code and can figure out where this behavior takes place? I'm curious if it can be easily disabled (if only to see what it's like).

Android has the concept of "touch slop", the value of which you can get ViewConfiguration:

http://developer.android.com/reference/android/view/ViewConf...

ScrollView views use this value internally to prevent accidental scrolling when tapping elements. You can change the touch behavior by subclassing ScrollView (or ListView) and overriding onTouchEvent() to ignore slop and start scrolling immediately on a drag event.

Incidentally, I can't stand most iPhone apps because of their over-sensitivity to scrolling (and their tiny list elements). I'm glad Android has these defaults.

Some lag is necessary in order to simply and reliably implement long-press actions, to distinguish them from drags. It's a bit like Windows ignoring small drags to help people make double-clicks on icons.

Not true - iOS (being held up here as essentially lag-free) has several long press actions. Closing running apps in multi-tasking and organizing apps require long presses.