Casey Affleck lobbies Mass. lawmakers to ban primate research

What's happening: Affleck wrote a letter to Massachusetts legislators urging them to prohibit separating infant primates from their mothers during the first year of life for research purposes.

Driving the news: The advocacy letter, sent to Sen. Lydia Edwards and Rep. Michael Day, chairs of the judiciary committee, supports H.1948/S.1167 ahead of a hearing Tuesday.

• Affleck references Harvard experiments that "sewed the baby monkeys' eyelids shut" and subjected them to strobe lighting during experiments.
• Animal welfare experts say practices like that cause lifelong psychological damage to primates.

Affleck said he finds experiments involving mother-infant separation "especially devastating."

• He praised Massachusetts leaders for working to make sure "this horrific practice never happens again in the state."

Zoom in: Affleck is upset about experiments Harvard neuroscientist Margaret Livingstone's lab conducted by separating infant macaques from mothers at birth.

• Animal rights groups condemned the methods and Livingstone's previous work that involved having the eyelids of some primate test subjects surgically closed for 12 months to study visual development.
• Over 250 scientists condemned the experiments as unethical and scientifically unnecessary.

The other side: Harvard has defended the research as "critically important" for developing treatments for tremor, Alzheimer's and brain cancer.

• Harvard stated that material from PETA, which Affleck cites in his letter, has used "misleading" information and "factual inaccuracies."
• The university says the research followed all federal animal welfare regulations.