Facebook has come under fire in the last few days after it was revealed the company had altered the news feeds of nearly 700,000 users in a psychological experiment. The scientists behind the experiment quickly put together an apology and explained the tests Facebook ran, but now one of the company’s top executives is speaking out about the project. COO Sheryl Sandberg called the experiment "poorly timed" and went on to apologize, reports The Wall Street Journal. "This was part of ongoing research companies do to test different products, and that was what it was; it was poorly communicated," said Sandberg. "And for that communication we apologize. We never meant to upset you."

During the one-week experiment, which took place in 2012, Facebook lowered the number of either negative or positive posts that users would see in their news feeds. The goal of the study was to learn how seeing more of each type of post affected what users were likely to share themselves. While Facebook’s terms of service allow for this sort of data manipulation, users found themselves concerned about potentially having their emotions manipulated as part of a research study that they weren’t aware of. Facebook data scientist Adam Kramer, who co-authored the study, noted that future research will take into account user reactions to this study — judging from the backlash currently surrounding Facebook, we imagine the company will be much more forthcoming around future studies