He does like talking about himself. But he may also be trying to generate a bandwagon effect, a well-documented phenomenon in political science but one that may leave him vulnerable to future disruptions.
.. They found that uncommitted participants in an online experiment were significantly more likely to back a candidate if the candidate was described as narrowly winning in the polls rather than narrowly losing.
.. If these theories hold, Mr. Trump’s promotion of his poll numbers not only threatens to undermine his appeal if he loses, but may also help his opponents rally their supporters against him.