A field experiment (Study 1, N = 228) and a questionnaire study (Study
2, N = 120) were conducted to investigate determinants of gratitude e
xpressions of British speakers. Based on Brown and Levinson's politene
ss theory, the main hypothesis was that the greater the giver's imposi
tion in benefiting the receiver, the more polite the receiver's expres
sion would be. Study 1 examined in four different situations participa
nts' responses to a giver who opened a door for them. The experimenter
's gaze and the extent of his imposition were shown to affect the resu
lts. Study 2 manipulated the extent of giver's imposition and the focu
s of the responsibility (neither receiver; giver). Tendencies to use m
ore polite expressions in the large-imposition conditions were as expe
cted and: were lessened in the giver-responsible situations. In additi
on, in receiver-or giver-responsible situations, apology-type expressi
ons were often used.