The experiment, designed to demonstrate “emotional contagion”, involved altering the news feed of nearly 700,000 Facebook users without their knowledge, and led to an ICO investigation and complaints to the FTC.

Previously, Sheryl Sandberg had said that the experiment had been “poorly communicated” but fell short of a full apology. But in a blog post last week, chief technology officer Mike Schroepfer said the company had been “unprepared” for the negative reactions it received when it published the results of the experiment, and admitted that it could have approached the work differently.

“It is clear now that there are things we should have done differently,” he wrote. “For example, we should have considered other non-experimental ways to do this research. The research would also have benefited from more extensive review by a wider and more senior group of people.

“Last, in releasing the study, we failed to communicate clearly why and how we did it.”

Schroepfer also said that the company has reviewed how it conducts research, and introduced a new framework outlining a new set of guidelines, a research review panel, research training and a new research website where all work will be published.