In an interview, Norman S. Matloff, a professor at the University of California, Davis, who has studied hiring patterns in the technology sector, said workers over 35 regularly face discrimination by technology companies.

Kris Stadelman, director of NOVA, the local work force investment board, which released a survey of human resource directors at 251 Bay Area technology companies last July, said that in her experience, candidates began to be screened out once they reached 40.

“Especially in social media, cloud computing and mobile apps, if you’re over 40 you’re perceived to be over the hill,” Ms. Stadelman said.