A visit to the park may lift the mood

Scientists have discovered that just spending time in leafy parks can improve the emotion and decrease the negativity of Twitter users for several hours.

The research, published on the pre-print site arXiv, supports the long-held link that open spaces are beneficial for physical and psychological wellbeing. Indeed, there are concerns that declines in the amount of urban park areas, and thus contact with nature, could adversely impact mental health.

Using Twitter to track people’s location and mindset, researchers led by Aaron Schwartz from the University of Vermont in the US investigated how visits to San Francisco’s large urban park system effects people’s states of mind.

By tracking the language used in tweets sent before, during, and after users’ visits to parks, the researchers could surmise mental affect – essentially, emotion at a given point in time. To do this, they used a brilliantly named model called a “hedonometer” to rate the words being used on a scale from one (least happy) to nine (most happy). For example, “sunshine” scored 7.94 while “traffic” has scored 3.34.

While affect scores fluctuated between roughly 6.1 and 6.2 for people not at a park, they reached 6.4 when users sent tweets surrounded by greenery. The biggest benefits were seen when users were at parks and playgrounds, with only a small boost seen from visits to civic squares – spaces which tend to feature less vegetation.

That benefit seemed to begin before the Twitter users had even entered the park, with a slight improvement in the hours before the visit. There was also an ongoing benefit, with elevated affect scores for around six hours after an outing.

The change in affect was seen to be due to a lower use of negative words such as “no” and “can’t”. The words “not” and “don’t” dropped by almost half. Tweets sent within parks also used more positive language, including “happy”, “young”, and “fun”, with “beautiful” appearing twice as often in park-tweets. “Me” dropped by 38%.

This, the researchers claim, is a clear indication of a reduction in negativity, and bolsters the evidence that parks and open spaces are valuable for improving mental health. Exactly what causes this benefit, though, is still up for investigation.

There are also questions about the findings themselves. Only around 24% of the US population uses Twitter, and only a proportion of them visited a park during the study period. There was also no way of tracking the age or social demographics of the users. Additionally, there is no way of knowing whether the effects carry over into different cultures or climates – visiting the park on a blasting hot summer’s day in Australia may illicit a different experience.