McMurphy discovers that Chief Bromden is not deaf when he is assigned a bed next to the Bromden. One night when McMurphy climbs into bed, he warns Bromden that one of the orderlies is coming to douse the lights. Bromden is startled when McMurphy says this.
After the snickering orderly ties the sheets on Bromden, he departs, and Bromden hears McMurphy next to him breathing deeply as the covers on him rise and fall. Soon, however, McMurphy begins a "soft, throaty sound" that develops into a low chuckle. Turning toward Bromden, he whispers happily,
"Why, you sure did give a jump when I told you that coon was coming, Chief. I thought somebody told me you was deef."
Despite learning Bromden's secret, McMurphy does not reveal the truth to anyone; he only talks to Bromden when no one else is around. For, Bromden pretends to be deaf because the orderlies will speak their "hate secrets" aloud before him. He also witnesses the hatred that Nurse Ratched has for these men in some of her responses to them, as well as her actions. Of course, McMurphy realizes that Bromden's opportunities to see and hear the real interaction that transpires with the orderlies and with Nurse Ratched may someday prove useful to him.