In Ray Bradbury's short story "The Veldt," there are many examples of foreshadowing. Foreshadowing is a literary device that authors use to give hints to upcoming events in the story. The first example comes at the beginning of the story:
“George, I wish you’d look at the nursery.
“What’s wrong with it?”
“I don’t know.”
“I just want you to look at it, is all, or call a psychologist in to look at it.”
“What would a psychologist want with a nursery?”
“You know very well what he’d want.”
It's clear from this conversation that Lydia is worried and that her concern is not a simple problem. She also hints that George knows what the problem is, as well. This grabs the reader's attention and makes them want to read on to find out what could be so wrong with a nursery that a psychologist would need to be called in to investigate.
The nursery in this story is a high-tech, interactive room that will project all the sensory information for whatever the children think about. If they think about a jungle, for example, they will see the jungle foliage, hear the animals, and even smell the smells located in the jungle. George and Lydia's children, Peter and Wendy, have been thinking about Africa lately. Their parents are disturbed because the sounds and smells are intense, the scenes violent. They don't want to see their "innocent" children interacting with such a raw and savage reality.
"The lions came running at them. Lydia turned suddenly and ran. Without thinking, George ran after her. Outside in the hall, after they had closed the door quickly and noisily behind them, he was laughing and she was crying. And they both stood shocked at the other’s reaction. “George!”
“Lydia! Oh, my dear poor sweet Lydia!” “They almost got us!”
The quote above foreshadows the fact that the children's fantasy of Africa and the lions is related to the children's plot to harm their parents.
"Remarkable how the nursery read the thoughts in the children’s minds and created life to fill their every desire. The children thought lions, and there were lions. The children thought zebras, and there were zebras. Sun – sun. Giraffes – giraffes. Death and death. That last. He ate the meat that the table had cut for him without tasting it. Death thoughts. They were awfully young, Wendy and Peter, for death thoughts. Or, no, you were never too young, really. Long before you knew what death was you were wishing it on someone else. When you were two years old you were shooting people with toy guns."
George is starting to understand that the children's thoughts are dark at this point in the story, but he still hasn't made the connection that these dark thoughts are directed toward him and his wife.
Later, when they're discussing the nursery being stuck on the veldt despite their efforts to change it to something more mild, Lydia observes this about the nursery:
“Or it can’t change,” said Lydia, “because the children have thought about Africa and lions and killing so many days that the room’s stuck in a pattern it can’t get out of.”
The nursery is supposed to change depending on what the user is thinking. George and Lydia try to think positive thoughts and even give the nursery direct commands to change, but it won't. This foreshadows the plot of the children.
There are more examples of foreshadowing, as well. The parents heard screams coming from the veldt, and they recognize that the screams sound familiar. This foreshadows their own screams as the lions attack them. There is also foreshadowing with the old wallet and bloody scarf that belong to George and Lydia. The lions have been given these items in order to find the parent's scent for an attack.