Decision Making, Social and Behavioural Influencing at Work: More Persuasive Arguments aren’t Always more Convincing

Recent study finds that presenting a greater number of persuasive arguments can leave people suspicious, rather than convinced. This has direct implications for leaders and managers trying to influence decisions at work.

If you want to persuade someone to subscribe to your point of view, as a leader you might feel you could put forward as many good arguments as you can think of. In many workplaces, influence is equated with having lots of strong points ready to go in a meeting, business case or presentation.

Well, not necessarily, according to the authors of Fifteen Reasons You Should Read This Paper in the Personality and Social Psychology Bulletin.

Previous work has found that, assuming the points you're making are compelling, providing many rather than few can be more persuasive. In a study that asked people to imagine serving on a jury, for example, participants who were given only one argument from the prosecution were less likely to feel that a fictional defendant was guilty than participants who were given seven reasons.

---

So on the surface, this fits with a common leadership habit: prepare more arguments to become more convincing.

---

However, this new research suggests that this approach might not be as fool proof as we thought. After a series of five online experiments involving more than 3,000 people, Abigail Bergman at Stanford University and colleagues report that in some circumstances, using more arguments in an attempt to bolster your case might actually not be so helpful.

When More Arguments Mean Less Influence

For leaders, that means more talking, more slides and more “reasons why” might not translate into more impact.

In an initial study, 590 participants read an email about a fictitious ballot taking place in their community. Half then read either nine arguments or just one in support of the ballot measure, supposedly from 'John', a community member. The participants' answers revealed that 'John' was seen as more of an expert when he provided nine arguments. However, they also felt that nine arguments showed more ‘persuasive intent’ as if he had an agenda.

Translate this to the workplace, and you get a familiar dynamic: the leader with many arguments is seen as knowledgeable, but also as “pushing an agenda”.

Earlier studies have found that when we feel someone is trying hard to persuade us, we can become suspicious. People start wondering what the real motive is. In organisations, this is where trust and psychological safety begin to wobble.

As the researchers show, the perceived expertise gained from many arguments is cancelled out by the suspicion created by persuasive intent. The net effect is no more influence than offering just one point.

The Trade-Off: More Arguments Boost Credibility but Raise Suspicion

A second study replicated the effect in a different setting: an advert for cold-brew coffee. Again, more arguments boosted perceived expertise but raised suspicion, cancelling out the impact.

The team then tested one, three or nine arguments about universal healthcare. More arguments increased both perceived expertise and perceived persuasive intent. The effects pulled in opposite directions, leaving the overall persuasiveness unchanged.

So the message for leaders is not about finding a magic number. It’s about understanding the trade-off: as you add arguments, you may be increasing both credibility and suspicion at the same time.

In some circumstances, expertise matters more to the audience (such as medical advice), and in others, low persuasive intent matters more (such as advertising). When participants were encouraged to prioritise expert advice, more arguments were compelling. When they were encouraged to look for low persuasive intent, fewer arguments were more convincing.

This maps neatly onto leadership situations. When people believe you are offering expert guidance in their interests, they may welcome more arguments. When they suspect you are selling a difficult change or pushing a preferred outcome, fewer and more carefully chosen points may land better.

Overall, the work challenges the popular idea that more arguments are always better. The researchers write: “Presenting many arguments even cogent arguments, often yields no benefit or can even reduce one's persuasiveness.”

Influence at work isn’t just about the quality of your reasoning; it’s about the level of trust people feel in your motives.

Practical action points for leaders

1. Start by naming your intent.
   When people understand why you are raising an issue, they are less likely to assume an agenda and more likely to engage with your reasoning.

2. Use fewer, clearer arguments when trust is fragile.
   One or two well-chosen points can build confidence rather than trigger suspicion. Leaders often gain influence by creating space, not by filling it.

3. Check whether your audience values expertise or low persuasive intent in the moment.
   If people are turning to you for specialist insight, more explanation may help. If people are wary of being pushed, keep it minimal and transparent.

4. Invite contribution early rather than presenting a fully formed case.
   This turns influence into a shared process. People tend to trust arguments they helped shape far more than those handed to them fully packaged.

5. Stay curious about resistance.
   A lack of persuasion isn’t always a sign you need more arguments. It could signal a concern about motive, a gap in psychological safety or a misalignment of values.

6. Balance conviction with openness.
   Strong positions are credible when paired with genuine willingness to hear alternatives. Your openness can do more persuasion than your arguments.