Tail lights, blinkers and break lights

[byrds6]

Just out of curiosity, how many lights should light up when I hit the breaks or turn on the blinkers? Only two light up when I hit the breaks and only 1 for blinkers and only 1 for when the lights are just on. I keep seeing some that all four light up when the breaks are on and some that all four blink. But then I see some that are just like mine. Its an 07 LT.