Ithaca, N.Y. – Cornell University said in a statement Monday that the two university-affiliated researchers who participated in a much-criticized Facebook study only had access to the results of the study and did not participate in collecting private data.

Dr. Jeffrey Hancock (Courtesy of Cornell University)

Dr. Jeffrey Hancock, a professor of communication and information science at Cornell, and Jamie Guillory, who was a Cornell doctoral student at the time, participated in a study that intentionally manipulated the news feeds of nearly 700,000 Facebook users, influencing whether the users saw more positive or more negative posts.

An article published this week by Slate called the study “unethical” and noted that it “intentionally made thousands upon thousands of people sad.”

Manipulating users’ news feeds without their informed consent may overstep federal law and human rights declarations, Slate said.

The work completed by Hancock and Guillory was limited to initial discussion, analysis of results, and preparation of the paper, according to a press release by John Carberry, a Cornell spokesperson.

The release says that Hancock and Guillory had no access to data at any time. A review by Cornell’s Human Research Protection Progam — which ensures the well-being of those used in research projects — was therefore unnecessary, Carberry said.

Here’s the full text of the press release:

“Cornell University Professor of Communication and Information Science Jeffrey Hancock and Jamie Guillory, a Cornell doctoral student at the time (now at University of California San Francisco) analyzed results from previously conducted research by Facebook into emotional contagion among its users. Professor Hancock and Dr. Guillory did not participate in data collection and did not have access to user data. Their work was limited to initial discussions, analyzing the research results and working with colleagues from Facebook to prepare the peer-reviewed paper “Experimental Evidence of Massive-Scale Emotional Contagion through Social Networks,” published online June 2 in Proceedings of the National Academy of Science-Social Science.

Because the research was conducted independently by Facebook and Professor Hancock had access only to results – and not to any data at any time – Cornell University’s Institutional Review Board concluded that he was not directly engaged in human research and that no review by the Cornell Human Research Protection Program was required.