"So I should keep a gratitude journal"

Somewhere around here a reader who's heard of this before will think of the notebook. Three things you're grateful for, written down each night. It's the standard advice, and you may have tried it and felt nothing, or found it saccharine, or done it for a week and stopped.

I'm not going to recommend it, and I'd rather tell you why than skip it.

The research behind it is real but smaller than its reputation. Robert Emmons and Michael McCullough ran the first studies in 2003. People were assigned to list things they were grateful for, or hassles, or neutral events, weekly or daily for some weeks, and the gratitude groups did better on several measures of wellbeing, though not all. The most reliable effect was on positive mood. A meta-analysis by Don Davis and colleagues in 2016 pulled together the studies since. Gratitude exercises beat doing nothing on wellbeing, with a modest effect. They beat a filler activity by a smaller one. And against a comparison that was itself designed to help, they did no better at all. The authors were honest about this. The exercises work a little, roughly as well as other active things a person might do, and not more.

So the notebook isn't nothing. But it's not the lever, and I think there's a reason it isn't. It's private. You write "the table" in a notebook and the table is noticed, but only by you. Nothing crosses the room.

There's a study that separates the two. Nathaniel Lambert and four colleagues, in 2010, looked at what expressing gratitude to a partner does to the person expressing it. In two surveys, people who told their partner what they were grateful for saw the relationship as stronger, and the expressing predicted that view rising over time. In the experiment, people were assigned for three weeks either to express gratitude to a friend, or to think grateful thoughts about the friend, or to think about daily activities, or to have positive interactions with the friend. At the end, the expressers saw the friendship as stronger than every other group, including the group that had only thought grateful thoughts. The measure was the expresser's own sense of the relationship, so it's a finding about how saying it changed the sayer. But it was the saying that did it, not the thinking.

That's why this book is about the thanks and not the notebook. The NHS, in its list of steps for mental wellbeing, puts "saying thank you to someone for something they have done for you" under giving to others, and I think that's the right category. It's not something you do for your mood, though your mood may benefit. It's something you do to another person, and it only works if it reaches them.

If the notebook helps you see the fine, keep it. Then say what's in it to the person it's about.