From The Anguish of Surrender: Japanese POWs of World War II, by Ulrich Straus (U. Washington Press, 2005), pp. 144-145:
Traditionally, Japanese have lived in a society that highly prizes the reciprocal giving and receiving of favors, including those exchanged between superior and inferior. Once drawn into a “human” (that is, emotional) conversational relationship with their interrogators, the prisoners realized that they had already received many favors from their captors. They had generally been treated decently. Of particular importance to the Japanese, they had not generally been insulted or humiliated. These Americans did not generally look down on them with contempt.[…]
In addition to all the material benefits they had received, some prisoners mused, the Americans had given them their life, if only by not killing them. For the Japanese, this huge imbalance of “favors” granted and received represented a serious problem. Many solved it by giving the Americans the only thing they had to give—answers to seemingly innocuous questions.
While Japanese prisoners were impressed by the material things the Americans shared with them, they were deeply affected by the more personal touches. They could not easily cast these aside saying the “rich Americans” could afford such things. It was not only that the Americans readily took out a cigarette from their own pack; more significant for them was that they were prepared to do so within plain sight of others. A few former Japanese POWs noted in their memoirs that they might have had the chance during the course of their military service to slip an American POW a cigarette. Now that the roles were reversed they were ashamed that they had lacked the courage to overcome the Japanese convention of the time, that all POWs of any nationality properly deserved total contempt. Prisoners so badly wounded that they could not even light or hold a cigarette were overcome with inexpressible gratitude when an order lit the cigarette and passed it from his lips to theirs.
Of all the many unfamiliar things the Japanese encountered in the prison camps, probably the most astounding was their medical treatment. They could hardly believe that prisoners received treatment identical to that accorded their captors. They would find themselves in hospital beds adjacent to beds occupied by their “enemy.” Even more astounding, American medical orderlies deigned to lift them up with their own hands and even clean them when they soiled their bed. That Americans gave officer status to nurses often amazed the Japanese. That these nurses would not only treat lowly enemy enlisted men but also at times give them a smile astounded them even more.
Discovering that they received the same food and in the same quantities as their captors surprised them as well. For a status-conscious Japanese prisoner who viewed himself as beneath contempt, such recognition of common humanity left an abiding impression. In this sense, the whole atmosphere of the prison camp became conducive to maintaining a civil, personal relationship with the Americans. While not designed for the purpose, in some instances this could only further American efforts to gain intelligence.