In 2018, Hal Pashler and Gail Heriot published a study showing that perceptions of newsworthiness tend to be contaminated by a political usefulness bias. In other words, individuals tend to view stories that give them "ammunition" for their political views as more newsworthy. They give credence to their own views. An evolutionary psychology explanation for why negative news have a higher news value than positive news starts with the empirical observation that the human perceptive system and lower level brain functions have difficulty distinguishing between media stimuli and real stimuli. These lower level brain mechanisms which function on a subconscious level make basic evaluations of perceptive stimuli, focus attention on important stimuli, and start basic emotional reactions. Research has also found that the brain differentiates between negative and positive stimuli and reacts quicker and more automatically to negative stimuli which are also better remembered. This likely has evolutionary explanations with it often being important to quickly focus attention on, evaluate, and quickly respond to threats. While the reaction to a strong negative stimulus is to avoid, a moderately negative stimulus instead causes curiosity and further examination. Negative media news is argued to fall into the latter category which explains their popularity. Lifelike audiovisual media are argued to have particularly strong effects compared to reading. Women have on average stronger avoidance reactions to moderately negative stimuli. Men and women also differ on average in how they enjoy, evaluate, remember, comprehend, and identify with the people in news depending on if the news are negatively or positively framed. The stronger avoidance reaction to moderately negative stimuli has been explained as it being the role of men in evolutionary history to investigate and potentially respond aggressively to threats while women and children withdrew. It has been claimed that negative news are framed according to male preferences by the often male journalists who cover such news and that a more positive framing may attract a larger female audience. However, other scholars have urged caution as regards evolutionary psychology's claims about gender differences. Bednarek, M. (2016). "Investigating evaluation and news values in news items that are shared through social media". "Corpora" 11(2): 227–257. https://doi.org/10.3366/cor.2016.0093)  Bednarek, M., and Caple, H. (2017) "The Discourse of News Values: How News Organizations Create Newsworthiness". New York: Oxford University Press. Bell, A. (1991) "The Language of News Media". Oxford: Blackwell. Brighton, P., & Foy, D. (2007) "News Values".