Writing in London's Evening Standard, journalist Matt Majendie calls it an obvious "personality make-over", after Jenson Button's manager Richard Goddard took over the handling of his career.
"(Goddard has) clearly had a word with the Force India driver", Majendie said, after some observers suggested part of the reason for the Scot not getting the call to a bigger team was due to his lack of charisma.
"In formula one, being media savvy and pleasing sponsors is as important as raw speed," said Majendie.
Asked on Thursday by F1's official website, 26-year-old di Resta acknowledged that he has taken the criticism on board and made a change.
"Yes, probably," he said.
"But relationships actually do grow over time, so I think it is also something about being in the paddock long enough to get a reputation and have people's confidence and take things and comments the right way.
"I think it has been a good winter to look at all possible aspects of change," he added.