When Harvard researchers sent a help request to multiple recipients, they got less help than if they messaged them one-at-a-time. To get even less help, they emailed one recip, with a cc: to others.

It’s true. They measured it. Really.

Conclusion: When you see a bunch of other recipients listed, you’re more likely to let somebody else do it.

Remember that next time you do an email blast.

See for yourself at cnet News.com.