Cultural amnesia

Every generation is handed a world that has been shaped by their predecessors – and then seemingly forgets that fact. Consider how we think about technology. The current generation's idea of technology means smartphones, cryptocurrencies or the internet, but it wasn't always so: technology was once centred on pneumatics or steam, rather than silicon. 
New generations also have a habit of collectively forgetting how positive social change comes about through the dogged activism of minorities once shunned, such as Emmeline Pankhurst and the suffragettes' campaign for women's right to vote. It wasn't always the case that universal suffrage was seen as uncontroversially right, yet this fact is rarely remembered. 
But if the most recent generation is forgetful about the positive steps and changes handed to them by their forebears, then so too can they fail to notice how those predecessors have damaged the world too.

A few years later, the psychologist Peter Kahn of the University of Washington described a similar effect in a completely different context: the black communities of Houston, Texas. He was curious about children's perceptions of the quality of the environment they lived in. Through interviews, he found that they could easily describe what air pollution was, for instance, as well as highlighting other cities that were polluted – but simultaneously they failed to show much awareness that Houston had become one of the US's most air polluted cities. They just accepted it as the way things were. "How could these kids not know it? One answer is that they were born in Houston, and most had never left it; and through living there they constructed their baseline for what they thought was a normal environment," Kahn later wrote in a paper he co-authored with colleague Thea Weiss.

According to Kahn and Weiss, we all experience this environmental form of generational amnesia. It is not so much that individuals fail to recall the past they themselves have lived, it's more that humanity collectively "forgets" the natural world as it once was, as the generations pass. "The problem is one of the most pressing psychological problems of our lifetime," they write. "It is hard enough to solve problems, like deforestation, ocean acidification, and climate change; but at least most people recognise them as problems."
Even the most familiar examples of nature, close to home, can be forgotten. Zoologist Lizzie Jones of Royal Holloway, London and colleagues recently interviewed people living in the UK about their perceptions and memories of 10 species of garden bird, both at the time of the survey and their recollection of when they were 18 years old. They found that younger people, who were closer to the age of 18, were less able to describe the true long-term ecological change that had happened among British bird populations. As Jones and colleagues pointed out, murmurations of starlings were once a common sight in the UK but their numbers in England alone declined by 87% between 1967 and 2015. Another example might be the "windscreen phenomenon", which describes the observation by all but the youngest generations that fewer insects are splattered on their cars nowadays.