The psychological tricks Angela Merkel used to congratulate Donald Trump say a lot about their countries’ future relations

“We look forward to working with you.” That’s what most world leaders have been saying to President-elect Donald Trump. Even, and in some cases especially, those heard expressing very different views in the course of the campaign. Good sportsmanship requires gracious congratulation of the winner.

The German response has been markedly different. Angela Merkel carefully expressed conditionality when she said she looked forward to working with Trump on the basis of “shared values of democracy, freedom and respect for the law and the dignity of man, independent of origin, skin colour, religion, gender, sexual orientation or political views”.

How world leaders respond to Trump’s election and their early exchanges with him are not just details of style or political approach. They are significant moments to express a sentiment and set boundaries. The new President-elect and his voters are feeling emboldened by victory, and they will be feeling validated and encouraged by a prevailing message of “welcome to the fold”.

Of course, most leaders will hope to work well with him – he has been elected President and there is much at stake. But psychologists have learned a lot about how people’s attitudes and behaviours develop, and how our interactions with them, in the early years and beyond, shape and inform their future behaviour. We know that despite the relative persistence of some aspects of personality, people behave differently in different contexts and in response to different cues. In this body of work there’s a concept called reintegrative shaming.

Reintegrative shaming is a way of expressing displeasure at bad and harmful behaviour. It does not say the person is bad, as doing so labels and marginalises that person by implying a fixed character, and consolidates exactly the behaviour that is not wanted, rather than inviting or facilitating change. Instead, it’s the behaviours, statements and style that are picked out for criticism: “You said and did some bad things,” rather than, “You are a bad person.”

This is important because it opens the door and shows a way back in – behaving in a way that would be more constructive, less divisive and harmful, more acceptable to others. The message received by the person who’s done wrong, and others who are watching, is: “We do not accept that kind of behaviour, but we look forward to working with you when you stop doing that.”

Merkel’s response to Trump’s election, her message to him, was in part an attempt at reintegrative shaming. While she avoided the explicit shaming, she set the boundaries around what would be acceptable behaviour and politics with which she would cooperate. We need more people with public platforms to be careful in what they say and how they behave. We know from experience that it is unlikely that the new President-elect will respond well to being shunned and hated. He has already shown himself to be keen to find ways to invalidate negative views about him.

But it is possible that he and his voters would notice and hear cues about what the international community will work with when he is President. And as importantly, those who are feeling vulnerable and threatened by the campaign statements will notice – as will all who care deeply about the values of liberal democracy.

This is a formative time for the world to set those boundaries now – both in the hope of getting the best leadership possible from the incoming President and his administration, and to clarify for ourselves and signal clearly to those around us what we believe is worth upholding.

Jennifer K Rubin is Professor of Public Policy at King’s College, London, specialising in justice and home affairs