In 1991, a lawsuit against R.J. Reynolds Tobacco accused the company of targeting children with its “Joe Camel” ad campaign. The ads featured a cartoon camel character that the suit said lured children to become smokers. Six years later, the company settled out of court and voluntarily ended the Joe Camel campaign.

This week, a group of psychologists launched a battle against a more nebulous foe: the role their profession plays in developing technology that hooks children to social media, video gaming and other digital habits.

Sixty psychologists signed a letter addressed to the president of the American Psychological Association “to call attention to the unethical practice of psychologists using hidden manipulation techniques … [that] increase kids’ overuse of digital devices, resulting in risks to their health and well-being.”

The signatories criticized colleagues who have helped the tech industry use “persuasive technology” that capitalizes on children’s developmental vulnerabilities to help sell digital products. In particular, it said, adolescent girls’ inherent need for social acceptance and fitting in makes them easier to pull into social media sites, while boys’ evolutionary need to rack up competencies makes them perfect targets for video games and their reward-based structure.

The letter linked gaming with unemployment, and social media use with depression and suicide-related behaviors, and it asserted that the role of psychologists in helping develop such tools runs counter to the APA’s mandates to “do no harm” and to not engage in subterfuge. It called on the organization to condemn psychologists’ role in designing technology aimed to keep children in front of screens, and to insist that psychologists and the tech industry be transparent about their use of persuasion tactics, techniques of which many parents and children are unaware.

“A lot of it is buried within the particular industry, and they sometimes don’t talk about it outside, but … these technology and social media companies make money by people staying on their screens for longer,” said Richard Freed, a psychologist who is one of the letter’s signatories and the author of “Wired Child: Reclaiming Childhood in a Digital Age.”

Understanding and employing psychological tactics is, of course, an inherent part of advertising. But Freed believes there is something more insidious going on. Psychologists help “to make products that are so stimulating and so good that they are better than real life, so their kids live their lives on them,” he said. “Overuse of tech has taken over their childhood.”

Jean Twenge, an author and professor of psychology at San Diego State University, said psychologists capitalize on the theory of motivation to develop ways to keep users on digital sites. “If you can do something that’s not too easy and not too hard, then you end up in this flow state and time ends up feeling irrelevant, and that’s great when you’re rock climbing but not so great when you’re spending 12 hours in a row on gaming.”

Arthur Evans Jr., the chief executive of the APA, said the organization does not have a formal policy regarding psychologists’ contributing to research and development of persuasive technology but is concerned about the increasing amount of time children spend on digital devices.

An APA survey last year found that attachment to and constant use of social media devices is associated with higher stress levels, and that many parents are worried about the effects of this attachment on their children’s mental and physical health.

“The impact of technology and psychology’s role in its development is becoming a major focus of APA’s work,” Evans said in an email, adding that “The APA’s Committee on Children, Youth and Families plans to discuss this letter when it next meets and will weigh whether to ask the association’s Board for the Advancement of Psychology in the Public Interest to examine this issue for possible action.”

Psychologists are not the only ones to raise the alarm about digital addiction. In recent years, tech executives themselves have warned that designers deliberately make products addictive. Former Google executive Tristan Harris, who now speaks out about the ethical responsibilities of the tech industry, told the Economist, “The job of these companies is to hook people, and they do that by hijacking our psychological vulnerabilities.”

Banning Joe Camel was one thing, but is it really possible to rein in experts who work in product development, and if that were possible, would doing it help?

Jen Romano-Bergstrom, a psychologist who is president of the User Experience Professionals Association, thinks not. Romano-Bergstrom, who has worked for Facebook and Instagram, describes her work as “ensuring that products match users’ expectations” and doesn’t think that the activity is as insidious as the psychologists’ letter implies.

Products such as social media or gaming are designed “for everyone, not just children,” she said, adding that she uses social media in positive ways, such as connecting people in small villages with the larger world where they might sell their goods.

Targeting those who work to develop such products seems to her the wrong approach. “Say you restrict psychologists from working on that market — it’s not like the research is going to end; it will continue,” she said. “Is the solution really to restrict them, or is the solution to educate our children on better ways to spend their time?”