Twitter has named Marjorie Scardino, former Pearson CEO, as its newest board member. Above, the Twitter symbol is displayed at the post where the stock is traded on the floor of the New York Stock Exchange, in this November 15, 2013, file photo. (BRENDAN MCDERMID/REUTERS)

Twitter announced Thursday that it has named Marjorie Scardino, former chief executive of Pearson, to its board of directors.

The appointment is effective immediately. Scardino will serve on the company’s audit committee; her term expires at the 2014 annual meeting of stockholders, according to a company filing with the Securities and Exchange Commission. She is Twitter’s first female board member.

Scardino and Twitter confirmed the appointment over their own official Twitter accounts — the message appeared to mark Scardino’s first tweet on that account.

Scardino had previously served as the chief executive of Pearson, a British publishing and education company, from 1997 to 2012. While there, she oversaw the company’s efforts to expand its education business and improve its technology. She has also served on the board of Nokia and worked at the Economist Group, where she was chief executive. She was also the first woman to lead a Financial Times Stock Exchange 100 company.

Scardino has been outspoken about the dearth of women on company boards. When she stepped down from Pearson in October 2012, the Telegraph reported, she said she wished she had effected more change in the gender balance at the company.

Twitter’s diversity problem: Vivek Wadhwa criticized Twitter for going public with no women on its board. He tells On Background that there is a lack of diversity across the company that starts at the top of it. (The Washington Post)

Scardino said she hoped that by the time she left Pearson the firm would be “different in terms of how many women there were as chief executives or chairmen or board members.”, according to the Telegraph report. “It’s not too different and for that I’m sorry,” she said,

Twitter has been criticized for a lack of diversity on its board — a criticism that extends to much of the technology industry. In October, a New York Times article noted that in the company’s filing to go public, general counsel Vijaya Gadde was the only woman listed in Twitter’s upper echelons. At that time, the article said, all the other executive officers, the named investors and the company’s board members were men. There are no ethnic minorities on Twitter’s board.

The Times article got a reaction from Twitter chief executive Dick Costolo, who discussed it publicly on the social network. Costolo said that increasing diversity in Twitter’s leadership had to be “more than checking a box and saying ‘we did it!’” and that the issues were “much bigger” than simply adding any particular type of person to Twitter’s leadership team.