Voters in the US are evenly divided over whether to regulate technology companies like Google, Twitter and Facebook that enable the targeting of users based on their political interests, according to a survey that suggests many Americans remain undecided over whether Silicon Valley is a force for good.

Forty-nine per cent of people said they would support regulating the targeting of news feeds, search engine results or advertising based on political affiliations or viewpoints, while 51% said they would oppose such regulation.

The question was one of several asked in October’s Harvard/Harris Poll at the request of the Guardian and comes amid growing talk in Washington about exploring ways to restrain big technology.

“These findings show that public opinion among voters is almost evenly split between the need for new policy to ensure more trust and privacy in social media, and preventing the reckless regulation of the internet and the curtailing of online freedoms,” said Dritan Nesho, chief executive of the research company HarrisX, which carried out the survey. “The jury is still out.”

The strikingly polarized result comes at a time when tech companies face intense scrutiny from US lawmakers as part of an investigation into Russian interference in the 2016 US presidential election.

Representatives of Facebook, Google and Twitter faced tough questioning at a Senate hearing on Tuesday. Colin Stretch, vice-president and general counsel at Facebook, struggled to answer an angry and incredulous Al Franken when the Democratic senator demanded to know why the social network accepted political advertisements paid for in Russian roubles.

All three companies will also testify on Wednesday before the House and Senate intelligence committees as part of congressional investigations of Russian election interference.

Anger over their role in Russian information operations is just one aspect of a rising tide of public discontent with Silicon Valley’s big tech firms. Once seen as the poster children for free market innovation, they now face scrutiny on both sides of the aisle for anti-competitive practices, tax avoidance and privacy-infringing data practices. In order to stave off regulation, tech firms have been pouring money into lobbying efforts in Washington to the point where they now outspend Wall Street two to one.

To understand American sentiment towards Facebook, Google and Twitter, the Guardian submitted questions to the nationally representative Harvard/Harris Poll, which surveys more than 2,000 registered voters each month.

Some of the questions mirror those that Facebook asks its own users in surveys conducted on the platform. Facebook does not release the results of questions it asks users, such as “Is ‘Facebook good for the world?” and “Does it care about its users?”

In September, the Guardian put those same questions to readers, and in October also submitted the questions, along with others about big tech, to respondents of the Harvard/Harris poll.

Thirty-two per cent of American voters agreed that Facebook was good for the world, although only 7% strongly agreed. Forty per cent of people were undecided, while 28% disagreed – half of them strongly.

Twitter appears to have a worse reputation, with just 20% of respondents believing that the company is good for the world. Forty-four per cent of people disagreed with the statement “Twitter is good for the world” –and more than half of those said they strongly disagreed with the statement.

Google was viewed most favorably, with 58% of people agreeing that Google is good for the world and just 16% disagreeing.

“Facebook creates a demand on your time – that’s a little onerous,” said Jeff Hauser, who tracks the lobbying spending of tech companies at the Revolving Door Project. “Google is a little more utilitarian.”

The results followed a similar pattern when people were asked if the tech companies cared about their users.

Google came out on top in terms of the proportion of people who agreed that it cares about it users (46%), compared with Facebook (26%) and Twitter (17%).

More than a quarter of people (26%) strongly disagreed with the notion that Twitter cares about its users, while 22% of felt the same about Facebook. Only 12% of people strongly disagreed that Google cares about its users.

“Facebook and Twitter are the two most powerful distributors of information in the world,” said Nesho. “Voters are aware of their amplifying force and their power when it comes to swaying policy and politics, and are increasingly concerned about it.”

“Reactions to the impact of these platforms to voters’ personal lives and the world are tepid or negative, making it important for Facebook and Twitter to address the problems of abuse, privacy, and trust that drive these views.”

The Guardian Facebook survey

Separate from the Harvard/Harris Poll, the Guardian asked its own readers about their perceptions of Facebook, using the same questions the social network asks its users. More than 3,700 people responded, and although their responses were not statistically representative, their answers also included written comments that explained their views.

When asked whether “Facebook is good for the world”, only 10% of Guardian readers agreed, 22% were on the fence, and 68% – considerably more than in the nationwide survey – said they either disagreed or strongly disagreed.

Concerns about the platform fell into several categories: some complained the social network had become too large and powerful, while others cited its ability to influence elections, its failure to effectively tackle fake news, its Orwellian data harvesting practices and its effects on mental health, particularly on children.

“Facebook has always been filled with immensely talented and driven people who have truly built something unique and world-changing,” said one reader. “But I also believe that the company has spun wildly beyond their control and been used in ways that they cannot combat.”

Another added: “Facebook was a good idea but has metastasized into a nightmare.”

“Facebook’s wide-reaching, non-transparent and unregulated power to shape public opinion is a grave threat to democracy,” said another. “America is empowering a new era of robber baron who want us to believe they are beneficent philanthropists.”

Eighty-three per cent of respondents to the Guardian’s survey disagreed or strongly disagreed with the statement that “Facebook cares about its users”, while just 6.5% agreed or strongly agreed.

“Facebook uses every psychological trick they possibly can to manipulate their users into spending as much time as possible on the site,” said a reader. “They clearly do not care for their users – they treat them as commodities to earn maximum advertising from.”

Replicating another question Facebook asks its users, the Guardian asked readers whether using Facebook made “the world better or worse for people who are going through a challenging or difficult time in their lives”.

Sixty-six per cent of Guardian respondents said the social network made things worse, while 12% said it made things better.

“As a doctor, I perceive it to worsen the mental health of vulnerable young people, teenagers in particular,” said one commenter. Another wrote: “In my own experience, Facebook use is addictive, as well as contributing to an exponential loss of concentration the more you use it, as well as heightened levels of anxiety.”

Positive comments about Facebook tended to focus on its ability to keep friends and relatives connected across long distances and its role in bringing communities together during natural disasters.

“Through Facebook’s messenger I am able to see my husband and children face to face everyday. We live in separate countries so this is enormously helpful for the emotional side of things,” said one reader.

“It’s great for keeping up with distant family and friends, and organizing the occasional event. It’s good at being a scrapbook,” said another. “When it moves beyond that into a purveyor of news and culture, it falls on its face. It needs more oversight.”

Many readers, however, argued that Facebook was simply a platform and could not be held responsible for its users.

“Facebook is often wrongly blamed for the poor behavior of bad people who use it,” said one respondent.

“Facebook is a tool,” said another. “It can be used for many different purposes – some good, some not good. The admins have a responsibility to make sure their algorithms aren’t causing harm.”

One commenter above all others summed up the complex relationship many people appear to have with the sprawling social network.

“I hate how it seems to steal my time. I love it when something amazing turns up. I dislike it when it blocks me occasionally. I love it when I have the opportunity to comment on an important event. Since I spend about eight hours a day on it, I guess I love it more than I realize.”