Rihanna Flaunts New Blonde Hair in L.A., Rocking Really Short Look

Rihanna seems to be putting an age-old theory to the test ... finding out if blondes really do have more fun -- 'cause she's rocking a short, light new hairdo!

The singer-songwriter stepped out in Santa Monica Friday, and her new look was instantly noticeable -- RiRi's usually lettin' her long locks flow, but now ... she's trimmed most of it off.

Just check out the pics ... her hair's not even touching her shoulders at this point -- a pretty sharp contrast to the Rihanna we normally see these days ... who lets her hair fall all the way to her hips. That's the 'do she's been sporting lately, anyway.

Also, peep the jewelry ... Rihanna's iced out with a necklace, earrings and bracelets -- shining bright like a diamond while on her way to an important meeting. It definitely accentuates the blonde hair up top ... and we gotta say, she's pulling the whole look off and then some.

Rihanna's look is noticeably different from one of the last times we spotted her ... as she was leaving Mukesh Ambani's son's pre-wedding bash in India with a swag bag and at least $6 million for her performance on the special day.

No word on how A$AP Rocky feels about the fresh cut ... but when your lady's RiRi, it's hard to imagine you can criticize much about her -- 'cause she's a beauty through and through.