"There's so much cool stuff in the world that they want to hold it all," says Lisabeth DiLalla, Ph.D., a developmental psychologist at the Southern Illinois University School of Medicine at Carbondale.
Toddlers are physical, so there's no better way for them to learn about an object than by picking it up. Plus, your child usually hasn't yet developed a right-or-left-hand preference, so if his right hand's full and he comes across something else interesting, he'll just grab it with his left.
Your child might also try to pick up more than he can hold, or put down one object to pick up another and wonder where the first one went. If he gets perplexed, let him figure out what to do, or gently demonstrate.
So, don't want him grabbing fruit in the produce aisle? Give him toys or intriguing household objects- one for each hand.