Prisoners should be learning professional skills that help prepare them for their release instead of being forced to work, sometimes picking crops in triple-digit heat for pennies an hour or nothing at all, Sen. Cory Booker said at a Senate judiciary subcommittee hearing on prison labor Tuesday. America locks up more people than almost any other country in the world — nearly 2 million — and they are disproportionately people of color. Those who refuse to work can be punished, including being thrown into solitary confinement, Booker noted.