♪ this is "nightline." >> tonight, whistle-blower. >> i believe facebook's products harm children, stoke division, and weaken our democracy. >> the former employee claiming what she says are the dangers to young people. >> one bad comment will just break you. >> critics say the tech giant is putting profit over safety. plus shannen doherty. >> oh my god. >> from "90210's bad girl" -- >> i was extremely rebellious. >> to cancer diagnosis. learning to live and work and thrive. >> i think i'm just starting to find moments of complete and utter honesty in my acting. >> and why she doesn't have a bucket list.

♪ ♪ ♪ ♪ ♪ ♪ hey google, turn up the heat. ♪ ♪ ♪

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is once again being scrutinized thanks to a whistle-blower. here's abc's senior national correspondent terry moran. >> i'm here today because i believe facebook's products harm children, stoke division, and weaken our democracy. >> reporter: that's frances houghen, the whistle-blower painting facebook as a giant with tremendous power but little responsibility. >> the decisions being made are disastrous for our children, for our privacy, for our democracy. >> reporter: she worked for facebook two years, leaving in may after her civic integrity unit was disbanded following the 2020 election. since that day she's been on a mission. >> as long as facebook is operating in the shadows, hiding its research from public scrutiny, it is unaccountable. left alone, facebook will continue to make choices that go against the common good. >> reporter: before she left the company, houghen copied

thousands of pages of internal facebook research she shared anonymously with "the wall street journal," documents she says show the social media giant knowingly stokes divisions, spreads misinformation, and harms younger users, all for its own profit. houghen revealed her identity on "60 minutes" on sunday. >> facebook makes more money when you consume more content. people enjoy engaging with things that elicit an emotional reaction. and the more anger that they get exposed to, the more they interact, the more they consume. >> reporter: the harvard business school grad describes a vicious cycle. >> i saw facebook repeatedly encounter conflicts between its own profit and safety. facebook consistently resolved these conflicts in favor of their own conflicts. >> their job is to keep you on the app, keep viewing ads, keep logging in, do nothing else but scroll on facebook and instagram. >> i really thought of facebook like a media company.

the power it wields is so much bigger. it has arguably the power of a country. >> reporter: adrienne la france is executive editor at "the atlantic." she compares facebook to a hostile foreign power. >> they're prioritizing engagement because that's what gets them profit. the way people are -- form a habit on facebook is by, you know, this sort of emotional reaction to extreme content. then the facebook algorithm notices that that is what is engaging you, then they show you more of that. >> reporter: most at risk, haughen told the senate committee, are our kids. >> kids who are bullied on instagram, the bullying follows them home. it follows them into their bedrooms. the last thing they see before they go to bed is someone being cruel to them, the first thing they see in the morning is someone being cruel to them. >> reporter: she leaked internal data she says shows the company knows instagram, which is owned by facebook, can be harmful to teen girls. >> facebook knows ice amplification algorithms --

things like engagement-based ranking on instagram -- can lead children from innocuous topics, like healthy recipes, to anorexia-promoting content over a very short period of time. >> reporter: an estimated 72% of teenagers are on instagram, making it a powerful force in their lives. >> being a teenager is rough enough in real life. and now that has carried over to the internet. >> reporter: britney hennessey created a program to help online influencers build their brand. >> for a teenager, constant access to what someone else is doing, there's a lot of fomo, a lot of comparison. add on that of that instagram, how beautiful everything is, how beautiful people are. it makes sense that you can logon to instagram and leave feeling worse about yourself. >> one of the things that we heard in this hearing today, facebook's own research shows that instagram harms teenage girls. how could your company know that, do research on it, and ignore it?

>> first, that's not an accurate characterization. and in terms of research, it's a very small survey of about 40 instagram teens who are struggling with mental health issues, and they were asked whether instagram makes things better or worse for them. on all 12 issues, the majority of both boys and girls who answered those questions said instagram either makes things better for them or has no material impact. >> reporter: the complicated relationship between young women's self-worth ask social media has been studied for years. >> you see somebody posting something, you get a bunch of comments on it, a bunch of likes. and that values your self-worth, when it really doesn't at all. >> say that like 100 good comments. you get the one bad comment -- >> it breaks you down. >> the one bad comment will break you. >> facebook understands if they want to continue to grow, they have to find new users. and the way they'll do that is by making sure that children establish habits before they have good self-regulation.

>> by hooking kids? >> by hooking kids. >> reporter: the 17-year-old company has huge global reach with nearly 3 billion daily users across facebook, instagram, and whatsapp. it's not just teenage girls. facebook has long been accused of doing little to temper misinformation and fomenting political violence. haughen says the january 6th attack on the capitol was fueled in part by changing guidelines the company had put in place before the election. >> you said facebook implemented safeguards to reduce misinformation ahead of the 2020 election but turned off those safeguards rye right after the election. and you know that the insurrection occurred january 6th. do you think facebook turned off the safeguards because they were costing the company money? >> facebook changed those safety defaults in the runup to the election because they knew they were dangerous. and because they wanted that acceleration of the platform - back after the election, they returned to their original defaults. >> reporter: and facebook did nothing to stop the widespread

violence against the minority rohingya in myanmar where the social media is the main source of news and information for millions. >> you've seen foreign actors carry out misinformation, dis-information campaigns using foong. ad targeting that goes after marginalized communities and tries to take advantage of them. the worst possible things you can imagine where facebook is the mechanism for carrying them out. >> reporter: today's hearing came a day after a massive outage that shut down facebook, instagram, and whatsapp for almost six hours. >> i think it was striking for a few reasons. certainly people who rely on these tools for businesses or communicating with family, that's disruptive. for work, it's disruptive. i this for some people, culturally it prompted self-reflection about, perhaps the reflexiveness to use these apps, what sort of role they play in their life. >> reporter: in a statement facebook apologized and said the outage was caused by a faulty configuration change and that there is no evidence user data

was compromised. but back on capitol hill, haugen and a bipartisan group of senators agreed that facebook must change. and that change has to come from ceo mark zuckerberg. >> mark has built an organization that is very metrics-driven. it is intended to be flat. there is no unilateral responsibility. the metrics make the decision. unfortunately, that itself is a decision. and in the end, if he is the ceo and the chairman of facebook, he is responsible for those decisions. >> the buck stops with him? >> the buck stops with him. >> reporter: the company agrees about the need for change, but not where it needs to come from, saying, we agree on one thing, it's time to begin to create standard rules for the internet. instead of expecting the industry to make societal decisions that belong to legislators, it is time for congress to act. some say regulation is coming too late. >> they've been doing morally objectionable things for years. and have only gotten more powerful. and so i think one

whistle-blower is hugely important for the public's knowledge of what's going on inside facebook, but it's going to take more courage and collective action, probably, for anything to really change. >> reporter: others say the only way to get facebook to change is for people to log off. but that hardly seeps likely. >> this is the time where you spend more time checking on your friends, your family, posting halloween photos, thanksgiving phot photos, christmas photos. this is the time we're on social media more than ever. so this could not be a worse time to expect people to log off. >> our thanks to terry. up next, "90210's" shannen doherty moving on from the bad girl days. how she's living with stage 4 cancer. a number. and mine's unlisted. try boost® high protein with 20 grams of protein for muscle health. versus 16 grams in ensure high protein. boost® high protein also has key nutrients

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♪ shannen doherty has felt the glare of the spotlight most of her life, making her television debut as a 10-year-old. the actress is opening up about her terminal cancer, how it's changed her and taught her to appreciate the little things. there's "nightline" coanchor juju chang. >> reporter: living life in the public eye has not always been easy for shannen doherty. her reputation cemented by her iconic bad girl role in the '90s classic "beverly hills 90210." >> oh my god, it was a very different time to be an actress. a lot of the men in the business were maybe not as collaborative

with women as perhaps they are now. because of that, i was extremely rebellious, and because of all the names, the labels that were given to me, i sort of retracted even more into myself and became even more defensive and even more shut down. >> reporter: but a cancer diagnosis changed all that. >> you really have to dig deep to face cancer. and in that, you find all the stuff that you had hidden away. you find the vulnerability. you find your trust in people again. you find forgiveness. >> reporter: after chemo and radiation, she had five years of remission. but in 2020, dougherty revealing her stage iv breast cancer. >> you want to own your cancer story? >> yeah, i mean, i'd rather people hear from it me. >> reporter: now she's opening up again about her story, determined to break the stigma and write a new narrative for people living and thriving with stage iv cancer. >> i'm living life.

i'm spending a lot of time with friends and family and working. work is -- it fulfills that creative side of me, and i definitely need that. i need to be fulfilled creatively. >> your birth mother is standing in your house? when were you going to tell us that you found her? >> reporter: dougherty is bringing her talents to two lifetime movies debuting this month, "list of a lifetime" and "dying to belong." >> my job as an actor is to entertain. and for people to have moments to escape. especially now. especially the world that we're living in. to be able to turn something on and sort of leave all of your problems behind, that's what i enjoy doing the most. >> does work feel different for you at this stage in your career? >> i think work was always very fulfilling to me. but in a way it's logic even more fulfilling. for me personally, my acting a

lot better now as well, because there's almost more of a well to draw off of. >> reporter: that fighting spirit, on and off screen, has always endeared dougherty to her fans. from "charmed" -- >> oh, who cares, we're desperate and it's working. >> reporter: to the recent "90210" reboot where she reprised the role that made her famous. >> i can't do this. >> reporter: and now, in her health battles. >> because when you tell people that you have stage iv met static breast cancer, the way people treat you changes, the way people look at you changes? >> they look at you like you're a dead man walking, basically. they need to say their good-byes to you or something. and also work drys up. i enjoy working. working gives me another reason to wake up every morning, it's another reason to fight to stay alive. >> when people first get diagnosed as stage iv, you can do a crazy google search and it

will tell you you've got two years, five years. it looks grim. of course, that is sometimes part of it for some people. but it's not for everyone. it goes back to what i said earlier. when you get diagnosed with something like cancer, a lot of people think that you're just done. it means that you're doing chemo, you're doing radiation. i did all of that, and i feel better than i've felt in the past with no cancer. i think i take better care of myself now. i eat better. i exercise more. i watch what goes into my body. >> give us a sense of where you are in your treatment plan and what's accounting for the fact that you look and feel so great. >> i'm still on my first protocol, which is a very, very, very big thing. it's kind of like -- you just want to last on your protocols as long as possible so that you don't run out of protocols. >> reporter: improvements in treatments and when they're given are known as protocols. they've increased life expectancy, making living with stage iv cancer for some more like a chronic disease.

but that doesn't mean dougherty's journey has been easy. >> when i got diagnosed the first time in 2015, it is -- like everything just goes out of your brain, and it's almost this empty moment. they're hooking you up to chemo, and your hair is falling out in clumps, can't get out of bed, you're throwing up, you can't eat. boy, it's humbling. and so to be humbled to that extent, you have to find the beauty. and once you find the beauty in such a dire situation, the whole world opens up to you again. >> that was a tour de force, you can drop the mic now, shannen, that was amazing. i know it sounds crish shea but it's also true. you've said in the past that you feel as though your diagnosis has allowed you to embrace the little things and the everyday in life. give me a sense of what that's like. >> i mean, again, going to cliche. i remember the first time it dawned on me. i was walking out of the parking

structure with my mom, and i just sort of looked up and i was like, is the sky always this blue? in that moment i just was, like, we are so lucky. like, each and every one of us are so lucky to be here. like, what a beautiful, stunning planet that we live on. so yeah, the little things have become huge things for me. and the huge things are no longer as significant. >> reporter: for the 50-year-old who's been working since she was a child on tv shows like "little house on the prairie," one significant thing that dougherty is not thinking of is her legacy. >> i mean, i don't think i've even come close to it, i don't think i've started on that path yet. for me, i feel like i'm just starting. i think i'm just starting to find moments of complete and utter honesty. and in my acting. >> you've been quoted as saying

you don't believe in bucket lists. >> i like to say those are goals. because a bucket list almost feels like those things that you check off before you die, and i never want to operate like that. i just want to operate as, i don't have things to check off, because i'm going to keep fighting to stay alive. >> our thanks to juju. up next, the finalists and the grueling competition. who is leading the pack in "fat bear week"?

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get started with xfinity internet for $19.99 a month for 12 months and add a flex 4k streaming box for free. click, call, or visit a store today. finally tonight, the competition to be crowned the fattest of the fat at alaska's katmai national park. the finalists in "fat bear week" have all been beefing up, prepping for their long winter hibernation. hundreds of thousands are voting for the biggest. walker has been packing on the

pounds. estimated to weigh at least half a ton. he's up against otis. a veteran, winner of the title three times since 2014. and just announced, drumroll, he's -- otis prevails once again. that's "nightline." you can watch all of our full episodes on hulu. we'll see you right back here at the same time tomorrow. good night. i'm morgan, and there's more to me than hiv. more love, more adventure, more community. but with my hiv treatment, there's not more medicines in my pill. i talked to my doctor and switched to fewer medicines with dovato. dovato is for some adults who are starting hiv-1 treatment or replacing their current hiv-1 regimen. with just 2 medicines in 1 pill, dovato is as effective as a 3-drug regimen... to help you reach and stay undetectable.