What does the monitor do?Would Ender have the same action to defend himself in chapter 1 if he'd still had it?

This device had allowed the authorities to view the world as Ender did. From Ender's thoughts we learn that the monitor has made him an outcast. Ender has the monitor a year longer than Peter which makes Peter insanely jealous. Peter, however, is pretty much a socio-path in the making. Peter would most likely have harassed his brother regardless of the monitor.