Starbucks wants to add training for store managers on ‘‘unconscious bias’’, chief executive Kevin Johnson says, after activists held more protests at a Philadelphia store where two black men were arrested after employees said they were trespassing. Johnson, who has called the arrests ‘‘reprehensible’’, said yesterday he hoped to meet with the men and apologise face to face. After a video of the arrests spread online, the hashtag #BoycottStarbucks trended on Twitter. About two dozen protesters took over the Philadelphia shop yesterday. The demonstrators want the employee who contacted police to be fired.