Story highlights Students in dorms without AC were 13.4% slower and scored 13.3% lower in cognitive tests than students with AC

"At a population level, we need to focus on modifying the environment so it's less hot," expert says

(CNN) We might be able to blame the heat for our bad decisions: A small study published this week found that college students who lived in dorms without air conditioning during a heat wave did worse on cognitive assessments than students who had air conditioning.

"To us, this is a way of saying yes, some of the effects are common sense, but what do you do about them?" said Jose Guillermo Cedeño Laurent, associate director of the Healthy Buildings Program at Harvard T.H. Chan School of Public Health and lead author of the study, which was published Tuesday in the journal PLOS Medicine . "And this is giving more precision to the opportunity of better controlling thermal environments in our buildings."

The researchers followed 44 university students in Boston between the ages of 18 to 29 for 12 days in the summer of 2016. The first five days were a seasonable average of 68.7 degrees Fahrenheit. The next five days saw a heat wave, which the National Oceanic and Atmospheric Administration considers a period of abnormally higher air temperature and humidity, and had an average of 92.1 degrees. The last two days were a "cool-down" period with an average of 82.6 degrees.

The students took tests right after waking in the morning that required them to identify colors on displayed words to appraise selective attention and processing speed and to complete basic arithmetic to evaluate cognitive speed and working memory.

During the heat wave, students without air conditioning had 13.4% longer reaction times and scored 13.3% lower on the tests than students in air-conditioned rooms, the study found.

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