Jonas learns about history through flashbacks the Giver transmits to him, clipped from other people's memories of the time before Sameness. A selection of the flashbacks appear in the novel as a motif to emphasize Jonas's emotional growth and learning. For example, in Chapter 13, the Giver transmits a disturbing flashback to the slaying of an elephant:
The Giver had chosen a startling and disturbing memory that day. Under the touch of his hands, Jonas had found himself suddenly in a place that was completely alien: hot and windswept under a vast blue sky. There were tufts of sparse grass, a few bushes and rocks, and nearby he could see an area of thicker vegetation: broad, low trees outlined against the sky. He could hear noises: the sharp crack of weapons—he perceived the word guns—and then shouts, and an immense crashing thud as something fell, tearing branches from the trees.
More than a story about the past, the flashback vividly engages Jonas's senses and the reader's as well. He feels the heat and sees the vegetation of what is probably the African savanna. He learns about guns by hearing their "sharp crack." He then hears the "crashing thud" and "tearing branches" that result from the elephant's fall. It is as though Jonas is actually on the scene with the elephant and its killers, even though this is not something he has ever experienced in "real" life. He finds the scene profoundly unsettling and replays it in his head over and over as he tries to sleep that night.
The flashbacks Jonas has Received up until this point have also engaged his senses. However, most of the sensations have been pleasant or even exciting. Jonas has been arguing that everyone should have access to all the memories he has been Receiving. He wants people to see color and to know what it is like to sled down a hill. The Giver has chosen to transmit this memory now because he wants his protege to understand that not all memories are as wonderful as the first one he gave the boy. Some of them are upsetting and painful. It is the duty of the Receiver to hold onto all of the joy and pain of history so no one else has to do so.
As the book goes on, Jonas experiences increasingly complex sensations and emotions by way of flashback. The actual content of the memories becomes less important than the way they open Jonas up to the full range of human experience. As he experiences more feelings and sensations, Jonas doubles down on his original idea that everyone should have access to the memories he is being given. Not only is it wonderful to experience the pleasure of a snowy day, he realizes, but it is also important to experience and witness pain. He comes to understand that his father's numbness and ignorance to pain is what allows him to kill a baby without a second thought. As a motif, the flashbacks allow readers to see Jonas to come of age in a fuller way than his father ever did.
The phrase "back and back and back" is a motif in the novel. For example, in Chapter 20, Jonas utters the phrase as he laments to the Giver that nothing can be done to stop the Community from killing people deemed useless to society:
Jonas looked up, puzzled. “A plan for what? There’s nothing. There’s nothing we can do. It’s always been this way. Before me, before you, before the ones who came before you. Back and back and back.” His voice trailed the familiar phrase.
The phrase is a mantra in the Community. Children like Jonas are taught from a young age to say it as a way of deferring to wisdom from the past. Generations ago, the Community established strict social rules and practices to create what they believe is a utopia, where everyone is free to forget the problems that the rules and practices were originally meant to address. They teach their children that it is inappropriate to ask too many questions about traditions. If something has been happening since a time "back and back and back," it must be correct. The phrase is what cult researchers call a "thought-terminating cliché" because it is a simple phrase that stops critical thinking in its tracks and reinforces commitment to the cult's ideology.
After seeing video footage of his father killing a baby, Jonas sours on tradition. Whatever the Community's rules say about population control, Jonas cannot accept that it is right to kill a baby simply for being the smaller of two twins. He is horrified that deference to tradition and lack of critical thinking have allowed his father, a man who adores babies, to commit such a casual act of cruelty. In the passage above, Jonas spits out the phrase "back and back and back" as a way of expressing defeat. He cannot stomach what his father has done and will surely do again. At the same time, he has spent his whole life learning that there is no changing tradition. The phrase is still working on him as a thought-terminating cliché: even though he is questioning the Community's ideology, the phrase nonetheless stops him in his tracks as soon as he thinks about fighting back.
As a motif, however, "back and back and back" represents more than the Community's totalitarian control over its citizens. Eventually, it also becomes the key to Jonas and the Giver's rebellion. Jonas and the Giver are uniquely positioned to see farther "back and back and back" than anyone else. By remembering what the world was like before the Community was established, the two of them are able to peek behind the curtain to reassess why certain rules and practices were created in the first place. They are able to think critically about their society in a way no one else can. The hope at the end of the novel is that Jonas can use Gabriel as a conduit to restore all these memories to the Community. In so doing, Jonas hopes to help them truly see "back and back and back" in time so that they can reevaluate their traditions.