The science of sadness

In 2016, Professor Stephen Hawking presented two lectures during the Reith Lecture Series at the Royal Institution in London.

While Hawking‘s lectures were focused on black holes, a particular passage is proving popular as an analogy for sadness and depression: “The message of this lecture is that black holes ain’t as bad as they are painted. They aren’t the eternal prisons they were once thought. Things can get out of a black hole both on the outside and possibly to another universe. So, if you feel you are in a black hole, don’t give up; there’s a way out.”

There’s much that science can explain about black holes. But what can it tell us about sadness?

What’s sadness?

If you Google ‘emotion’, chances are you’ll come across Dr Paul Ekman. In the 1970s, Ekman identified six core emotions that he proposed were experienced by all humans, irrespective of culture, language, ethnicity, or geography. These core emotions were surprise, fear, anger, disgust, happiness and sadness. Ongoing research has demonstrated the effect of emotions on behaviour, judgement, and decision-making – we tend to avoid things that scare us; we smile when we’re happy. What about sadness?

“Sadness is typically a response to the loss of something or someone important,” says Dr Peter Koval, emotion researcher and senior lecturer in the School of Psychological Sciences at the University of Melbourne. “Usually, sadness is experienced when that loss is perceived to be permanent or irreversible.”

Many emotion researchers consider sadness (like other emotions) to have evolved because it serves important functions.

While it’s easy to label sadness as an unhelpful emotion, Koval disagrees: “Because of its unpleasant tone, sadness is [often] considered a ‘negative’ emotion, but that doesn’t imply that it is useless, harmful, or even always undesirable. In fact, many emotion researchers consider sadness (like other emotions) to have evolved because it serves important functions.”

A study in sadness

Experimentally, sadness is often induced through prompts such as sad film clips or the recollection of painful events from the past. Researchers often go to great lengths to provoke an ongoing feeling of sadness in study participants. One particular study, published in Emotion, asked participants to focus on the death of a loved one – including details such as their final words, their appearance at their death, and any “unsuccessful” attempts to “comfort the loved one as he or she died”.

But while research into sadness can be, well, sad, it has provided several interesting psychological insights, including an association between sadness and cognitive functioning.

Researchers often go to great lengths to provoke an ongoing feeling of sadness in study participants.

For example, the study published in Emotion found sadness to be associated with negative memory bias – with ‘sad’ participants remembering significantly more negative words (as opposed to positive or neutral words) when compared to ‘control’ participants in a memory task. This study also found participants in the sad condition to perform significantly worse in a task aimed at recognising emotion-based facial expressions.

Another study, published in Aging, Neuropsychology, and Cognition, suggests that sadness can influence how we perceive sadness and happiness in others. In this study, older and younger participants in the ‘sad’ condition rated sad faces as significantly ‘sadder’ than participants in the ‘neutral’ condition. In addition, older participants in the sad condition were also found to rate happy faces as being significantly less happy than older adults in the neutral condition.

Experimentally, induced sadness has even been found to reduce olfactory (sense of smell) sensitivity. It’s a finding that becomes even more interesting when one considers that a number of studies have found reduced olfactory sensitivity in patients with major depressive disorder.

It’s not all bad news

Many emotion researchers consider sadness to serve important functions – both socially and cognitively. One such function is the role of sadness in facilitating social support: physical expressions of sadness communicate to those around us that we may need help. “Think of how you’d respond to child sitting alone at the entrance to a shop if she was crying versus smiling,” says Koval.

Sadness can also promote cognitive and behavioural changes that allow us to process and adapt to loss.

“Sadness demotivates further action in the face of loss or failure,” says Koval. “This is useful in environments that are not conducive to achieving one’s goal – there’s no point endlessly persisting with an action that has so far been fruitless – it’s useful to stop and re-assess.”

Sadness is also found to be associated with rumination (the tendency to reprocess the same thoughts over and over). Koval believes that this process too has it merits. “Although [rumination] can often involve feelings of self-blame and shame, which are very unpleasant,” says Koval, “it can also help [in identifying] the cause of a loss, a plan for the future to avoid similar loss, or a recalibration [of] unattainable goals or beliefs.”

“Sadness demotivates further action in the face of loss or failure. This is useful in environments that are not conducive to achieving one’s goal… it’s useful to stop and re-assess.”

– Dr Peter Koval, University of Melbourne

Experimental work has also found a number of other surprising outcomes associated with induced sadness. One such study, published in the Personality and Social Psychology Bulletin, found sadness to increase fairness in a series of experiments involving participant allocation of resources – while happiness was found to increase selfishness in the same tasks.

Other experiments have found induced sadness to increase politeness and the ability to form effective persuasive arguments. Sadness has also been found to significantly decrease the human tendency to form judgements of others based on first impressions alone.

But while experimental research on sadness is fascinating, is it actually representative of sadness in the real world?

‘Real world’ sadness

COVID-19 has had an unimaginable impact on the world – but it has also provided an opportunity to examine the effect of a global pandemic on psychological health. While experimental research undoubtedly has a place in scientific methodology, the ability to study sadness in the real world offers its own unique insights.

“In the lab, sadness is typically studied by exposing people to relatively standardised stimuli like pictures or films,” says Koval. “These approaches are really useful because they ensure a degree of uniformity and control over potential confounding variables that could influence whatever outcome the researcher is studying. However, these methods also limit how much we can generalise from the lab to daily life.”

Studying sadness in the real world is not without challenges. If we consider research undertaken during COVID-19, the ability to compare the same group of people before and after the initial outbreak is limited.

COVID-19 has had an unimaginable impact on the world – but it has also provided an opportunity to examine the effect of a global pandemic on psychological health.

Nevertheless, studies undertaken during the pandemic provide an interesting insight into psychological health during COVID times. For instance, a study in New Zealand examined more than 2000 responses from surveys conducted during the country’s first lockdown. Researchers found that 30.3% of respondents reported moderate to severe psychosocial distress (a measure of anxiety and depressive symptoms) – well above baseline measures obtained using the 2018 New Zealand General Social Survey.

Another study conducted in the Netherlands followed students for 14 days during a time of rapidly increasing COVID-19 infections and deaths. While anxiety and loneliness were found to remain stable or even decrease during this period, depressive symptoms were found to increase.

Research in France found participants feeling significantly less happy during lockdown than before lockdown restrictions. This experience of decreased happiness, along with sleep disturbances, was also associated with a feeling of ‘time slowing down’ during the lockdown period.

A better understanding

Sadness is a complicated emotion. But it’s through the study of emotion that we better understand ourselves and others. “Emotions permeate every aspect of our lives,” says Koval. “They influence our thoughts, judgments, decisions, and everyday behaviours… understanding emotion should matter to people because it can help us make sense of our own and other people’s behaviour.”

So, the next time you are feeling sad, remember that sadness is not a useless emotion – and in Stephen Hawking’s words: “…look up at the stars and not down at your feet.”