With things truly hotting up, we look at the psychology behind selfies, cat videos and emojis. Meanwhile, the autopsists turn their well-sharpened scalpels away from Labour and onto the Lib Dems. And we find out how nudge technology could help you avoid the five most dreaded words in the English language: “Unexpected item in bagging area”.

Of course, no special edition would be complete without a Guardian live blog of the weather. But if things are getting a little too warm for your liking, then head on up that ladder to seek shade and refuge amid the psychosocial refuse in Charlie’s Attic.

David Evans
Director

• Behaviour Change ~ We explain the psychology of selfies, cat videos and emojis
• Polls, Policies and Politics ~ Find out which of the Labour candidates Tories say is too hot to handle
• Health Hub ~ The new “heat wave killer” – and how to avoid it
• Values Lab ~ Take a look at our heat map of...well, heat
• Charlie’s Attic ~ More click bait - how Britain’s animals are keeping cool

• Struggling to get what you want? According to a new report, it may be down to your negotiating skills. And words, according to researchers, speak louder than actions.
• “Unexpected item in bagging area” are, we’re sure you’ll agree: the five most annoying words in the English language. Well, Rory Sutherland has been to Nudgestock, where he’s discovered a way of using psychology to make self-service checkouts almost tolerable. And on the topic of everyday minutiae, Business Review Weekly has some nudge “hacks” – including useful advice on how to word an invoice to ensure it gets paid on time.
• Meanwhile, new research suggests that boosting your self-esteem isn’t about how many friends you have, but how many groups you belong to.
• Not “living in the moment”? Good, says Dan Gilbert, who thinks we could all do with living in the moment not more – but less.
• Love the Harry Potter series? Well, next time someone tells you they’re just for children, you can point out that the series has a lot to teach us about personality, psychology and politics.
• Meanwhile, Courtney Seiter gives us the psychology of selfies, and asks whether they’re good or bad for us. On a similarly puerile theme, have a look at this psychology of cat videos and of emojis.
• Cognitive dissonance may play a bigger role in determining people’s voting patterns than beliefs and values, claim political scientists at Harvard and Stanford.
• It has been claimed that Facebook’s recent “Celebrate Pride” tool, which allowed users to add a rainbow filter to their profile pictures to celebrate the US Supreme Court’s approval of same-sex marriage, may have been a psychological test to monitor how views spread.
• And finally, Robbie Gonzalez takes on a difficult topic at a difficult time, and asks why people still defend the Confederate flag?

• With the leadership campaigns now well underway, Liz Kendall has refused to retreat in her bid to win back Tory voters. Perhaps it’s working – a survey of Tory councillors shows that Liz Kendall and Caroline Flint are their most feared candidates.
  o   Also this week, now it’s your turn to wield the scalpel: Labour wants your feedback on its election campaign, and promises to read every submission.
  o   Writing in the Guardian, Matthew d’Ancona claims that George Osbourne’s greatest victory is to have redefined not only the Conservatives, but Labour too. Meanwhile the Independent warns Labour that a failure to defeat Osbourne now, would see him become PM in 2020.
  o   And could we soon see an English Labour Party? That’s what Jon Cruddas has claimed, and he thinks it could be launched as soon as next month.
• 2015 hasn’t been a great year for the Lib Dems. But as they’re set to see an increase in their number of Peers, could their luck be on the turn? And after revelations that Nick Clegg offered to resign as early as 2014, experienced autopsists Patrick Wintour and Nicholas Watt ask whether the Lib Dems sold out or just lost their way.
• Meanwhile, in education, a new report urges the DfE to give white working class pupils extra help with English, to close the emerging gap in results.

• For those of you taking to your sun loungers, proceed with caution: BBC News has advice on how to spot the signs of heatstroke, “the heatwave killer”.
• And, a new report finds that children in England are the least fit they have ever been.
  • Researchers have suggested that there may be a link between sedentary behaviour and anxiety.
  • And while weighing yourself every day may help you lose weight, the aptly-named Chris Stokel-Walker tramples all over claims that to remain healthy we must walk 10,000 steps every day.
• And are e-cigarettes really safer, or is it all just another smokescreen from the tobacco industry to make its products appear safer?
• And finally, research suggests that extending cancer testing could save 5,000 lives a year through earlier diagnosis.

• Read about how China accused Michael and Emily Eavis of engaging in “anti-China splittist activities” after the pair booked the Dalai Lama to appear at Glastonbury Festival.
• Look at Simplenote, billing itself - in true Ronseall style - as “the simplest way to keep notes”.
• Convinced? If not, read this article by Simon Jenkins, who asks whether we have entered a post-digital age.
• Looking for love? Get a dog, say researchers.
• Help out Greece, by donating to this bailout fund on IndieGoGo, currently at almost €1.5 million.
• Take a look back in time – or at the Spectator – to see how history and culture shape the current Greek crisis.
• Put the current heatwave into perspective, by reading about the world’s hottest countries.
• Find out about the mildly tasteless Terminator pun gone viral.
• Look at Longleat’s monkeys, London’s gorillas, Chester’s chimps, and – most charmingly of all – Greater Manchester’s rail passengers keep cool by tucking into free ice lollies.