Conventional wisdom has been turned on its head by the findings, which suggest the best way to present information to students is to do nothing at all with it.
Researchers have raised concerns about an "over-abundance of handouts" that might actually have the opposite of the intended effect, by reducing students' ability to think and write about a subject.
The findings show that when students were given the same information in three different ways, they performed best when they read a sheet of plain text.
But when the same information was presented in a formatted way - with bullet points and important issues underlined - performance was considerably worse.
The study, by two researchers based at Perth College, Emma Clayes and Kyle Smith, presented the same information on Macbeth in three different ways, then assessed Higher English students with the same test on content and analysis.
Students who used an unformatted transcript scored an average of 1930. Another set of students received the information via a podcast and got 1530. But those who used handouts of formatted text did worst by some margin, scoring 1230.
There were also clear differences in how the handwritten answers were structured. Those who had read the plain text wrote longer answers with proper sentences and paragraphs, but those who read the formatted text wrote in a more informal way.
Only 13 students took part in the study last year, so Dr Clayes and Dr Smith were cautious about their results and carried out another this year - with "very similar results".
They also undertook a study with Higher psychology students. Those with plain text scored 810 and wrote more sophisticated answers.
That was in stark contrast to those given formatted text, who scored 610 and, most strikingly, appeared to mimic their handout - writing with bullet points and underlined headings above short, discrete sections.
The research was presented at the annual researchers' conference in Perth last week and prompted an enthusiastic response from a member of the inspectorate. She said students were "bombarded by handouts", which often led to complaints from them that "this is really complicated". She was also frustrated that handouts meant students were less likely to take their own notes.
"I've heard teachers say: 'They don't know how to take their own notes,'" she said. "They actually just need more practice and more understanding about what makes a good form of note-taking."