Neural networks used to map out human emotions in London and San Francisco

An analysis of geotagged tweets from London and San Francisco has shown people's emotions depend on where – and when – they are in the city.

Dining out or relaxing on the waterfront makes people happy; spending time in transit or at the office does not. Similarly, people tend to express the most positive emotions during the weekends, leaving frustration for days like Wednesday, according to new research from the Kyoto Institute of Technology in Japan.

Using computer systems known as neural networks, a team of researchers analyzed two million geotagged Twitter posts published in London and San Francisco in 2016 and 2017. Tweets were dissected based on where and when they expressed anger, anticipation, disgust, fear, joy, sadness, and trust.

In both cities, the highest level of negative emotions, such as anger and disgust, was reserved for transportation locations, including train stations, bus stops, and bridges. According to researchers, it reflected the frustration experienced by people waiting for transportation or stuck in traffic.

Negative emotions also tended to concentrate on sports and entertainment venues such as stadiums, the research found. People tweeting from these locations showed a high level of anger, fear, anticipation, and sadness.

"This is understandable as these were emotions which tended to be associated with the participation and viewing of sports activities – being fearful and sad when the team they are supporting is losing," the study said.

On the other end, hotels and restaurants elicited strong positive emotions. The high level of joy in this category could be explained by people tweeting about their food and holidays, researchers said.

Tweets from locations with water-related activities, such as swimming pools, sailing ports, and coastlines, also showed high levels of joy. At the same time, hospitals, dentists, and doctor offices saw high degrees of fear and sadness.

The day of the week or specific events also affect emotions. In San Francisco, emotions spiked during Donald Trump's inauguration and the 2017 Women's March, showing high levels of anger, anticipation, and disgust. In London, fear and sadness spiked during Westminster and London Bridge attacks in 2017.

"A similar result was also discovered when analyzing tweets during the Paris and Brussels attacks, where emotions such as anger, sadness, and anxiety tend to spike on social media a couple of days after the event," the study said.

Seasonal events such as New Year's Eve, Valentine's Day, and Christmas week see high levels of joy, as do weekends. Negative emotions are most prevalent on weekdays.

"Higher levels of negative emotions during Tuesday and Wednesday could perhaps be explained by people trying to get through the middle of a working week," the study said.

It also found that anticipation spikes on Thursdays and Fridays, ahead of a weekend, and drops on Sunday as a new working week is about to start.

The study results were published by Plos One, a peer-reviewed science journal.