The decision

Up to now I've asked you to notice things and perhaps to speak to the man in the paper shop. This chapter asks you to decide something. It comes this late on purpose. Without the last twelve chapters, the rule below would be one more piece of advice to be sociable, and you've had plenty of that.

The decision is this. When I think of someone, I get in touch that day.

The rule is small because its size is what makes it work. It isn't a resolution to be a better friend. It doesn't set a target for nights out. It takes something that already happens to you several times a week, which is a person crossing your mind, and attaches one action to it. It might be a song or a street, or a name in a list on the way to the plumber. At the moment those thoughts arrive, produce a pang and go away. Under the rule each one becomes a message, sent the same day, in the three sentences of chapter 12. "Heard that song today and thought of you. How are you doing?"

It has four parts.

The warm-up. Start with the easy ones. In the last of Aknin and Sandstrom's studies, the researchers tried to get more people to message an old friend. Earlier attempts to change people's attitudes hadn't worked. What worked was practice. One group spent three minutes sending messages to current friends and acquaintances, people they were already in touch with. The other group spent three minutes browsing social media. Afterwards everyone had the chance to message an old friend they'd lost touch with. In the social media group, 31 per cent did. In the practice group, 53 per cent did. So before you message the name in the list, message three people you spoke to last month. Say anything friendly. It takes three minutes and it makes the harder message more likely to get sent.

The rule itself. For the next month, every time someone comes to mind and you feel the pang or the warmth, send the message that day. Don't weigh whose turn it is. Don't check how long it's been. You thought of them, and that's the reason to write. If it's late at night, write it and send it in the morning.

One arrangement a week. Messages open the way, but chapter 11 said they shouldn't be where contact stays. So once a week, make one first move towards hearing a voice or seeing a face. Suggest a date for a coffee, set up a call, or ask a neighbour in for tea. One a week is modest. Over a year it's fifty occasions that otherwise wouldn't have happened.

The weak ties. Keep up the extra sentence in shops and over hedges, from chapter 10. It costs nothing and it keeps you in practice.

Plans in the form "when this happens, then I'll do that" are well supported. Peter Gollwitzer and Paschal Sheeran pooled 94 tests of them and found they made people a good deal more likely to follow through. Here are three, and you can adjust the wording.

When someone comes to mind and I feel the pang, then I'll send them three sentences before the day is out.

When I catch myself thinking "it's their turn" or "it's been too long", then I'll take that as the signal to write.

When someone says "we must catch up", then I'll reply with a date.

The second plan takes the thoughts that have been stopping you and treats them as the cue to act. "It's their turn" is what the wait sounds like from inside. Hearing it in your head is the most reliable sign you'll get that there's a message worth sending.

Here's what to expect, and I'll be careful, because I can't promise you an outcome. Most messages will get a warm reply, often quicker and warmer than you predicted. Several will contain some version of "I've been meaning to get in touch for ages", which is chapter 3 confirmed. Some replies will be slow. A few messages will get a brisk answer or none, and the next chapter deals with those. Not every revived contact will become a revived friendship. Some people you'll exchange news with once and leave it there, and that's fine. What I'd expect after two or three months is a phone with more conversations in it. I'd expect a diary with a few more entries, and a weaker sense that nobody ever rings. Some of them will have started ringing, because people tend to ring those who've recently rung them.