According to some witnesses in the life of Marylin Monroe, including her first husband and her niece, Norma Jean Mortensen would have been synesthetic.
« She has that displacement of the senses which others take drugs to find »
« He recounted evenings when all Norma Jean served were peas and carrots. She liked the colors. She has that displacement of the senses which others take drugs to find. So she is like a lover of rock who sees vibrations when he hears sounds…It also provides her natural wit… she did not have a skin like others. »
« Synaesthesia is a term Marilyn and I were unaware of; in the past, we simply spoke of the characteristic experiences with terms such as ‘extraordinary sensitivity’ and/or ‘extraordinary imagination’… Marilyn and I both studied acting with Lee Strasberg, who gave students exercises which could bring us awareness of such abilities, and the means of using them to bring characters to life. As you know, the varied experiences can bring sadness or enjoyment…Marilyn’s awesome performance in “Bus Stop” (the one she was most proud of) grew out of the use of such techniques and quite wore her out. Ms. Miracle believed that not only was her aunt a synaesthete, but that she, too, is one. The trait is known to run in families. »
Reference : Psychology Today