You can say that again. And again. And again...

Ever wondered why so many politicians endlessly repeat themselves? Apart from having nothing new to say, it's a deliberate ploy aimed not so much at our long-suffering ears, but our brains.

Scientists call it the illusory truth effect - the more we hear something repeated, the more likely we are to believe it is true. It doesn't really matter if the statement is true or false, either. Our brains are wired in a way that processing the familiar requires less effort than trying to comprehend something complicated or unknown.

"If you tell a lie big enough and keep repeating it, people will eventually come to believe it," claimed Joseph Goebbels, the Nazi's minister for propaganda. Don't believe we are that gullible? Consider how quickly fake news spreads. Or ask the advertising industry how many tooth whitening products they sold last year.

This year's federal election campaign is less than a week old but there's a good reason why it already feels like Groundhog Day. Yesterday Scott Morrison was sticking to the mantra he introduced last weekend when he announced the May 21 polling date. "People know me," he said for the umpteenth time. "Some people disagree with me, some people agree with me. Some people don't like how I saw some things and other people do. You know who I am."

His thoughts on Anthony Albanese? "He has stood for everything he's opposed and he's opposed everything he's stood for ... who is this guy? ... No wonder people don't know who he is ..."

Morrison is a skilled hustler on the hustings who often sounds like he is auditioning for a role as the voiceover man for Hollywood movie trailers because he loves. To speak. In dramatic. And very repetitive. Short sentences.

In Tasmania to promise $220 million for the native forestry industry, he was asked about broken election pledges from 2019 including the planting of a billion trees (only 1 per cent of the target met so far) and his failure to set up a federal integrity commission. He promptly dismissed the questions as either untrue or the fault of bushfires, floods and an uncooperative opposition, and then returned to his script without blinking.

Albanese's campaign has so far been in stark contrast, with the Labor leader criticised for waffling and wandering off script. It happened again yesterday on the subject of refugee boats. Labor would "turn boats back," he said. "Turning boats back means that you don't need offshore detention." Confusion followed. Did that mean he had abandoned his party's formal policy of supporting offshore detention centres? Albanese had to stage a later doorstop interview clarifying there had been no reversal in policy.

We all might complain that politicians spend too much time repeating their favourite slogans and failing to expand on their policies. But science tells us something else. We tune out when confronted by details and complicated concepts. It's the message and the mantra that ultimately mesmerises us.

Enjoy your Easter break and a brief respite from the white noise of the election campaign. We'll be back Monday morning and we'll try not to repeat ourselves...

HAVE YOUR SAY: We've been inundated with your views about the need for four- or five-year fixed parliamentary terms. We'll bring you a wide selection in the coming days. But keep sending us your thoughts. Echidna readers continue to disprove the great myth of politics - that Australians don't care. You clearly - and passionately - do. Are Australians less apathetic than we think? Send us your views: echidna@theechidna.com.au

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IN CASE YOU MISSED IT: Australia's unemployment rate remained at 4 per cent, with 17,900 jobs added to the economy although the number of monthly hours worked fell by 10 million ... A poll released by the Australia Institute showed overwhelming public support for a national integrity commission, with support highest among Coalition and Labor voters ... the Nationals announced $55 million to transform Newcastle airport ... The Greens pledged $500 million to assist steelmaking industries and regions move away from coal.

THEY SAID IT: "The problem with political jokes is that they get elected." - Henry Cate.

YOU SAID IT: "I mentally and morally applaud four- to five-year terms for government. But the thought of another three years of ScoMo makes my stomach ache!" - Anne.

"A five-year term would be a good move. Apart from having fewer elections, it would make the sitting government more responsible for its policies and actions." - Bob.

"Four-year terms would be an extra year's break from this tedium of election campaigns. Please, let's just do it." - Valerie.

"Most of Australia is desert or semi-desert with very limited potable water and arable land. With increasing extreme climate change, the reality is we are struggling to support our current population. The coastal fringes cannot sustain the enormous pressure being placed on it, so migration needs to be restrained." - Murray.

"The population problem is a worldwide problem. If we didn't have so many people we would not have climate change. Solve that one." - Ray.

"'Affordability' is a made-up word that enables politicians to avoid saying 'price'. The only way to make housing more affordable is to reduce house prices, but no party will admit this. They all claim the mutually exclusive positions of being the best party for young aspiring buyers and for house owners." - Bob.

"Population growth for its own sake is a con job. The inescapable fact is that compound growth of anything eventually makes everything unsustainable. The real issue is how much is a sustainable and stable population and what steps do we put in place to achieve this." - John.

"Where will the water come from to support all these people?" - Elisabeth.

"The link between 234 years of human population growth here in Australia and 234 years of environmental decline is both causal and correlative. So long as we grow our human population, everything else will be compromised. The question arises, therefore, when will enough be enough? I think that point arrived some time ago." - Graham.

"A very wise uncle told me that there will be world wars over water. The way that land is being swallowed (and agricultural land at that!) is the main reason for a lot of our world's troubles. Too many people..." - Yvonne.