You've probably heard the phrase "what doesn't kill you makes you stronger", either from Kelly Clarkson or Nietzsche. In both versions, and as the phrase is now generally used, it basically means you get stronger by facing adversity.
"It's become almost like a cultural touchstone," Eranda Jayawickreme, a psychologist who has researched "post-traumatic growth" told Hidden Brain. "It's almost like a default attitude towards trauma that we believe that when bad things happen we are going to use it as an opportunity to become better."
But is there any truth behind the phrase? Well, it's complicated, and even if there is some truth behind it, it still might not be helpful as concept, according to Jayawickreme.
Some research has suggested that growth (and more satisfaction with relationships), as well as an improvement in self-esteem, can come after traumatic events.
"A positive trend has been found for self-esteem, positive relationships, and mastery in prospective studies after both positive and negative events," wrote the authors of a paper published in the American Psychological Association.
"We found no general evidence for the widespread conviction that negative life events have a stronger effect than positive ones. No genuine growth was found for meaning and spirituality. In the majority of studies with control groups, results did not significantly differ between event and control group, indicating that changes in the outcome variables cannot simply be attributed to the occurrence of the investigated life events."
One of the problems with research into the area is you can't (unless you go back to the early 1900s and crack on) induce trauma in your subjects. This means that you are relying on the memories of subjects about their pre-trauma lives in order to get your data, asking them to self-rate how they are now vs how they were before.
One group of researchers got around this, by essentially keeping the study going long enough for trauma to occur. In a study published in Psychological Science, researchers asked 1,200 undergraduate students – chosen because they were "at the peak age for trauma exposure" – to fill in a range of questionnaires designed to measure satisfaction around areas of life thought to be affected by traumatic events.
They then waited two months, before giving the students the same questionnaires, as well as a questionnaire around life events that had happened in the intervening time, and a typical post-traumatic growth questionnaire asking participants about changes to themselves following the traumatic experiences. This last questionnaire included rating statements such as ‘‘I have a greater feeling of self-reliance’’ and ‘‘I have a greater sense of closeness with others".
In the months between the stages of the study, 122 of the students had experienced a highly-traumatic event (one example given by the researchers is "a close friend killed by a drunk driver") and had rated those events as having caused extreme distress.
"It would be inappropriate to conclude from our findings that people cannot change in positive ways following threatening life experiences," the team wrote in their discussion. "Indeed, a relatively small proportion of our participants demonstrated actual change, although we have no way of knowing if this change can be attributed to their traumatic experience."
However, looking at the measures of satisfaction around life collected at both stages of the study, there was little correlation between perceived growth by the participants and improvement in these psychological measures.
"All of this suggests that retrospective reports of growth measure something different from actual pre to post trauma change," they added.
As well as not being clear-cut, it's possible the concept of "what doesn't kill you makes you stronger" could be harmful to people who have recently experienced trauma.
"Think about what it communicates: Suffering is good in the long run, and people who have experienced trauma are stronger than those who haven’t," Jayawickreme and fellow psychologist Frank J Infurna wrote in a piece on the topic for The Conversation. Those who are still struggling months or years after a traumatic event may feel "weak" if they haven't experienced the same "growth", they add.
"People can indeed grow from adversity. They can become stronger, improve the quality of their relationships and increase their self-esteem. But it probably doesn’t happen nearly as often as most people and some researchers believe."
"Nor should growth be thought of as a goal for everyone. For many people, just getting back to where they were before the trauma may be an ambitious enough goal."