Earlier this year, activists opposing the war in Gaza marched onto the Golden Gate Bridge and Interstate 880 in Oakland. They blocked traffic for hours, some chaining themselves to vehicles or cement-filled drums. Twenty-six were arrested and charged.

Similar scenes played out across the United States -- perhaps most controversially on college campuses, where students found themselves banned, suspended and expelled -- in this latest chapter of the global "age of mass protests". Participants in historic uprisings from Hong Kong to Paris to Sidi Bouzid have braved tear gas, rubber or real bullets, imprisonment and even set themselves on fire while standing up for their beliefs.

Headline-making demonstrations raise questions about what protesting requires of us: Are huge risks necessary to engender social change? Do I personally need to step in front of moving cars, spend a night in jail or launch a hunger strike to advance the causes that matter to me? Does my social media post, bumper sticker, lawn sign, signature on a petition or attendance at a peaceful rally still make a difference?

According to social science, strenuous and risky protest does tend to make a bigger impact than protest involving lower effort and risk. But studies also show that slacker activists -- slacktivists, who stick to low-cost, mostly online activism -- play key roles in successful movements.

Costly protest, like when demonstrators suffer violent repression, sends a strong signal to the media, voters and power holders that activists mean business. If someone is willing to spend hours of their time, endure discomfort and even put their life on the line for a cause, their grievances come across as more genuine than those of someone who spends a few seconds typing "#MeToo" or "#BlackLivesMatter". (One caveat is that violence initiated by protesters, albeit costly, almost always backfires--nonviolent campaigns across the 20th century were more than twice as effective as their violent counterparts.)

Some protesters bear significant costs simply by virtue of their social identities. Demonstrators from minority groups frequently endure harsher repression than their white counterparts; women face backlash for daring to speak out against the patriarchy; and low-wage hourly workers pay a higher economic price relative to their income to attend a protest than salaried professionals with flexible schedules.

Though unfair, these disproportionate costs also empower protesters by amplifying their messages. Research by political scientist LaGina Gause reveals an "advantage of disadvantage" whereby lawmakers are more likely to support the preferences of low-income and minority protesters than the preferences of more privileged protesters. Ass Prof Gause highlights how protests concentrated in minority and low-income communities of Los Angeles after the acquittal of the police officers who beat Rodney King exerted electoral pressure on Southern California Republican Congressman Jerry Lewis. Lewis, whose Inland Empire district sat just east of LA, switched his normal voting behaviour to endorse the Dire Emergency Supplemental Appropriations Act of 1992, a Democrat-sponsored bill to fund relief for businesses destroyed during the protests.

While costly protest packs a punch, scholars also emphasise that activism is not all or nothing. "Slacktivists" strengthen movements in two critical ways.

First, they provide numbers. Hardcore veteran activists are exceptional. Usually, they cannot fill the streets on their own, so they must recruit greener activists into their ranks. One study of the Arab Spring showed that turnout by "peripheral" protesters with few previous activist connections contributed more to rising protest rates than turnout by "central" protesters with numerous Twitter followers. Movements, like viruses, need "fresh blood" to spread.

Second, including casual activists in a protest or movement helps to generate common knowledge about shifting social norms. If even your politically apathetic cousin starts posting "#BlackLivesMatter", it becomes more socially acceptable for others in their network to endorse that cause -- and eventually awkward not to. While support for BLM in the general population has dipped from its high of 67% in 2020, a majority of Americans continue to support it. Ideas that were once fringe, like gay marriage and universal healthcare, became mainstream in part through ordinary internet users normalising them, often from the comfort and safety of their couches.

A common concern is that slacktivism breeds complacency: If people are content to blast words of solidarity with their phones, they may never feel compelled to take up more demanding modes of activism that movements also need to meet their goals. "Someone still has to go to prison," argued techno-critic Evgeny Morozov in The Net Delusion: The Dark Side of Internet Freedom.

Fortunately, evidence from multiple countries indicates that dipping your toes in online activism makes you no less likely to perform costlier gestures such as demonstrating, attending political forums or donating to charity. Slacktivists are not destined to remain slacktivists. Online activism can open a gateway to protesting in real life and to deepening one's investment in a cause.

If slacktivists are ultimately harmless, and even beneficial, for social movements, then why do they get such a bad rap? For instance, some fans of Taylor Swift and other celebrities chose to unfollow their idols on social media for not speaking out forcefully enough about bloodshed in Gaza. Journalists branded these ex-Swifties as slacktivists indulging in empty virtue signalling rather than undertaking more meaningful action. Why did these former fans provoke such ridicule if they were not really hurting anyone?

The answer has to do with the fact that we are hardwired to judge others by the costs they inflict, or are unwilling to inflict, on themselves. This explains our instinctive admiration for courageous, selfless activists like Martin Luther King Jr and our disdain for timid, "fake" activists who send nearly costless signals of their political commitments by, say, sporting an awareness ribbon or unfollowing insufficiently "woke" celebrities. Higher risks earn greater rewards.

However, we would be wise to refrain from wagging our fingers at slacktivists. For one thing, most of us behave like slacktivists at one point or another. Michelle Obama and Malala Yousafzai took flak for tweeting "#BringBackOurGirls" after armed extremists kidnapped more than 270 Nigerian schoolgirls in 2014, but it is difficult to seriously question their activist bona fides. As First Lady, Ms Obama spent countless hours on the Let Girls Learn initiative, and Ms Yousafzai won the Nobel Peace Prize for promoting girls' education in Taliban-occupied Pakistan.

More importantly, shaming slacktivists can discourage them from attempting any kind of activism at all. The savvy organiser strives to make activism more -- not less -- accessible by sharing their wisdom with newcomers. Building a truly inclusive mass movement calls for patience and humility on the part of status-conscious movement leaders. This is its own form of sacrifice for a cause: the sacrifice of one's ego. Community-engaged scholar Biko Mandela Gray implored fellow activists, "Let us check our egos at the door of political engagement and resistance, and remember that our wellbeing is always connected to the wellbeing of the whole".

Some slacktivists will blossom into the next generation of devoted changemakers, whereas others will continue dabbling. And that's OK. Both types of people have roles to play in the collective pursuit of justice. ©Zócalo Public Square