Final answer:
The man's attitude of overconfidence and his dismissal of experienced advice is captured when he thinks of the oldtimers as 'womanish', believing solely in his self-reliance, leading to his crucial mistakes and death.
Step-by-step explanation:
The passage that provides the strongest clue to the man's attitude contributing to his death is:
"Those oldtimers were rather womanish, some of them, he thought. All a man had to do was to keep his head, and he was all right. Any man who was a man could travel alone."
This reflects the man's disregard for the advice and experience of others who are more familiar with the severe conditions of the Yukon. His overconfidence, ignorance of the environment's risks, and decision to go alone ultimately lead to his failure to build a fire.