Two of the key motifs in this excellent novel are the perception of size and the power of laughter. An interesting aspect of Bromden's narration is the way that he describes the size of people not based on their appearance but based on the way that they are controlled or control others. This is why although he is six feet seven inches tall, at the beginning of the group he describes himself as small. He tells McMurphy that "I used to be big, but not no more." Nurse Ratched, on the other hand is "big as a tractor" because she controls so many others, Bromden himself included. However, during the course of the novel, thanks to the intervention of McMurphy, Bromden regains his real size as he builds up his self-esteem, individuality and sexuality.
Laughter is another key motif, particularly focused in the character of McMurphy, who, as Bromden and the other patients see him for the first time, sounds out a laughter that is in stark contrast to the patients and his surroundings:
He stands looking at us, rocking back in his boots, and he laughs and laughs. He laces his fingers over his belly without taking his thumbs out of his pockets... Even when he isn't laughing that laughing sond hovers around him, the way the sound hovers around a big bell just quit ringing--it's in his eyes, in the way he smiles and staggers, in the way he talks.
McMurphy's ability to laugh is in marked opposition to the patients' inability to laugh, as they can only smirk and smile behind their hands. For McMurphy, laughing is synonymous with sanity, and his ability to laugh in the face of the craziness of life actually is shown to keep him sane. Key to realise is the way that on the fishing trip, the other patients laugh for the first time for a long time, indicating their move from insanity towards sanity.