Loving-kindness practice, metta in the tradition it comes from, involves deliberately cultivating goodwill towards a sequence of people — oneself, a close person, a neutral person, a difficult person, and eventually all beings.
It's substantially less popular than attention-based practice and has a comparably good evidence base.
The structure
The traditional form uses phrases repeated with attention, directed towards a person held in mind.
Formulations vary and typically wish for wellbeing, safety, health and ease.
The sequence matters. Starting with someone for whom goodwill comes easily establishes the feeling, which is then extended progressively to people for whom it's harder.
The difficult person stage is where the practice does its distinctive work and where most people struggle.
What the research has found
Studies of loving-kindness and compassion practices have reported effects on several measures.
Positive emotion. A well-known study found that a practice programme produced increases in daily positive emotions over time, with associated increases in personal resources.
Social connection. Studies have found increased feelings of social connection and positivity towards others, including after quite brief practice.
Implicit bias. Some studies have reported reductions in implicit bias towards outgroups following loving-kindness practice, though this literature has the replication difficulties affecting bias research generally.
Self-criticism. Compassion-focused approaches, which draw on similar practices, have evidence for reducing self-criticism and shame, and are used therapeutically.
Chronic pain and illness. Some studies have found benefits in these populations.
Effect sizes are generally modest and the methodological limitations affecting contemplative research apply here too.
Why it's harder than attention practice
Several reasons practitioners report.
Self-directed goodwill is difficult. The traditional sequence begins with oneself, and a great many people find this the hardest stage rather than the easiest.
Teachers working with Western practitioners have observed this frequently enough that some suggest starting elsewhere and returning to oneself later.
It can feel false. Repeating wishes for someone's wellbeing when you don't feel it produces a sense of pretending.
The traditional response is that the practice is cultivation rather than expression — you're generating something rather than reporting it, and the initial artificiality is expected.
The difficult person stage surfaces material. Directing goodwill towards someone who has harmed you can bring up anger, grief and resistance.
Traditions generally advise starting with mildly difficult people rather than the most difficult, and this advice is frequently ignored.
Backdraft. A term used in compassion-focused work for the phenomenon where opening to kindness surfaces the absence of it — where receiving or generating warmth brings up the memory of its lack.
This is recognised in the therapeutic literature and is a reason to approach the practice gently, particularly with difficult early experience.
The distinction from positive thinking
Worth drawing because they get confused.
Loving-kindness practice does not involve believing that a difficult person is good, or that a situation is fine, or that you should feel differently than you do.
It involves wishing for wellbeing, which is compatible with acknowledging harm, maintaining boundaries and holding somebody responsible.
Traditional commentary is explicit that this isn't approval and doesn't require reconciliation. Wishing that somebody be free from suffering is not the same as wanting to be near them.
That distinction matters practically, because the practice is sometimes presented in ways that imply forgiveness or reconciliation, which is not what it asks and which can be actively harmful in some situations.
Practical suggestions
Start where it's easy. If self-directed goodwill is difficult, begin with someone straightforward — a person, a pet, a child — and return to yourself later.
Use phrases that fit you. Traditional formulations are available and the words matter less than the intention behind them. Phrases that feel false in your own vocabulary produce resistance.
Don't force the feeling. The practice is repetition with attention, not manufacturing emotion. The feeling arises or doesn't, and the practice continues either way.
Choose mildly difficult people for that stage. Working with the most difficult relationship early frequently produces overwhelm and abandonment of the practice.
Short sessions. Ten minutes is adequate and sustainable.
And if it consistently produces distress rather than difficulty, that's worth working with somebody rather than continuing alone.
Why it deserves more attention
The contemplative practices that reached wide adoption were the attention-based ones, which fit a secular framing readily.
Loving-kindness fits less easily, since it's explicitly about how you relate to other people, and it has evidence at least as good.
It also addresses something attention training doesn't. A practice that improves concentration doesn't necessarily make anybody kinder, and the traditions considered the second at least as important as the first.
The compassion distinction
Related practices that traditions distinguish and that popular presentation frequently merges.
Loving-kindness wishes for wellbeing. Compassion practice is directed specifically at suffering — wishing for its relief, and cultivating the capacity to remain present with it rather than turning away.
The distinction matters practically for people in caring roles. Research on burnout in these professions has distinguished empathic distress, where taking on another's suffering becomes overwhelming, from compassion, which involves warmth alongside the recognition of suffering.
Some studies suggest these have different effects, with compassion training associated with better outcomes than empathy training alone in terms of sustaining care without exhaustion.
Which suggests the practice has specific relevance to people whose work involves continuous exposure to suffering, and it is not generally taught to them.