Previous research has found that participation by young people in an i
nternational expedition organized by the British Schools Exploring Soc
iety is associated with positive change in a variety of self-report pe
rsonality dimensions. The purpose of the present study was to suppleme
nt self-report questionnaire data with observers' ratings made by expe
dition leaders. The coping strategies used in relation to the physical
and social stresses of the expedition were also assessed. Finally the
relationship of optimism to both coping and personality processes was
studied. The leaders' ratings showed stronger evidence of personality
change than self-report measures. The correlations found between self
-report measures and observer ratings of personality dimensions sugges
ted that the expeditioners' self-perceptions were affected by the expe
dition and converged with the ratings of observers. Analysis of coping
processes indicated that several strategies were used less in coping
with a specific stress such as an expedition than they were reported a
s being used in general. Physical and social stresses of the expeditio
n were handled differently, confirming the distinction between these t
wo types of stress. In general the results expand upon current researc
h on stress and coping, with the opportunity that an expedition provid
es for studying the same stress in a predictable sample of subjects.