Interview Directory 

BOOKS

Name: Prof. Michael Saller

Profession: Professor of Business Law, Author

AM: Prof Saller, how did you come to specialise in this area professionally?

S: I started out as a lawyer and then worked for several years as an investigator at the Federal Cartel Office. There I investigated major white-collar criminal cases such as tendering and price-fixing cartels. These investigations in cartel proceedings also included questioning possible perpetrators and many witnesses. I also completed various training courses, including at the police academies in Neuss and Hesse. I then moved to the OECD in Paris and realised that many of the interrogation techniques can also be used in normal conversations. 

I've been a professor since 2020 and also teach contract drafting, among other things. Before you can draw up contracts, you first have to negotiate them, and an important part of negotiating is gathering information. 

AM: Despite all the scientific interrogation techniques, mistakes can happen. How do you deal with the responsibility when someone has been wrongly convicted?

S: Even though I was working as an investigator at the time, there was still a judicial review in two instances. And finally, there was a trial in dubio pro reo. There are certainly false convictions, often based on false confessions, but not in my cases.

‘Lies often remain in a certain grey area.’

AM: In hindsight, do you realise that you once made an error of judgement? 

S: Every now and then I believed people because I thought they were absolutely credible. Later it turned out that these people were lying. There are only limited ways of recognising lies. Lies often remain in a certain grey area.

‘A lie is often very, very difficult to expose unless you go deeper.’

AM: Have you ever met the perfect liar?

S: Alfred Hitchcock once said that the proof of the perfect crime is that you never find out. There are people who lie very, very well, but you get other evidence and then you can prove that person lied.

It also depends on how much time you've spent with that person and how closely you can investigate the whole thing. A lie is often very, very difficult to expose unless you go deeper.

AM: How do you recognise that someone is lying? 

S: There are many credibility criteria. For example, if the statement can be told consistently over a longer period of time or if detailed questions about less important details can be answered. If someone doesn't fulfil any of these credibility criteria, then that's a warning sign. However, there are also people who tell stories without details because they have a poor memory. This is not necessarily a lie, but it is a warning sign.

It is suspicious when people claim facts that cannot be verified. Liars are very fond of doing this because the whole thing cannot be verified.

‘But the lie detector can also be manipulated. By doing mental arithmetic, by thinking about something else in the meantime.’

AM: What elements of body language are suspicious?

S: There is no single characteristic by which you can recognise lies. Many people think that liars look in the eyes, but according to scientific studies this is not true because liars know that this prejudice exists.

Liars take countermeasures because many things in body language can be controlled. Things like touching your nose or drinking with a dry mouth are seen as signs of lying. Of course, liars can control these things and then deliberately not do them.

You can't control your pupils from dilating. But that doesn't necessarily mean you're lying, it mainly means you're agitated. And of course innocent people who are being questioned are also excited. 

AM: Do lie detectors provide a reliable result?

S: With the right technique, the so-called knowledge-of-the-deed technique, there is a

95 per cent probability. This means that you ask something that only the perpetrator can know. Then there is a certain rash in the heartbeat and sweat, which can be seen with a 95 per cent probability. However, the lie detector can also be manipulated. By doing mental arithmetic, by thinking about something else in the meantime. 

AM: Can we learn from poker players?

S: In the film Rounders with Matt Damon, John Malkovich breaks open an Oreo biscuit when he has a good hand and looks at the filling. Poker players spend a lot of time seeing if they can read each other's body language, but they don't rely on it. ‘Poker tells’ are interchangeable. Playing poker is probability maths  

‘At the moment, two different extremes can be observed, such as rather uncritical interviews, e.g. Karin Miosga with Robert Habeck.’

AM: Then you also discuss interrogation models in your book and also thematise journalistic questioning. At the moment, journalists are already interrupting their interviewees in the second sentence and chaos breaks out.

S: At the moment, two different extremes can be observed, such as rather uncritical interviews, e.g. Karin Miosga with Robert Habeck. Or the interview where the journalist begins with a very tough question or perhaps even an insult. The journalist also wants to show a certain attitude. A show effect is also important in journalistic interviews. Jan Fleischauer said in an interview he gave to Der Spiegel that he was once almost physically attacked by an interviewee. That would have been good material for television, he said.

But I believe that the simpler method works much better. Namely, you let people talk first. That way you get the information and then you can ask the difficult questions later. 

‘You can ask comprehension questions that summarise what the other side has said and show whether you have really understood it. It's also a way of showing respect for the other side.’

AM: Which of the methods you presented is your favourite?

S: I think that active listening is very important at the beginning, so listen to what he has to say and then follow up with good questions. You can ask comprehension questions that summarise what the other side has said and show whether you have really understood it. That's also a way of showing respect for the other side.

AM: In the tragic Gäfgen case, there were threats of torture and the policeman was convicted and even lost his pension.

S: He wanted to save lives and it is actually completely understandable to want to save the life of a child. But according to the German rule of law, torture must not be used under any circumstances, not even under extreme circumstances, because human dignity comes first. Basically, it was similar in Guantanamo. There is a book about the enhanced interrogation in Guantanamo. The author had carried out the torture himself, was not ashamed of it and even wrote a book about it. He explained that he had prevented many assassinations and saved thousands of lives. But in Germany, no matter what the circumstances, torture is never permissible.

‘Lying weakens your position in the long run and makes everything more complicated.’

AM: If you have so much to do with lies in your job, what is your moral approach?

S: There is the assertion that life would not be possible without lies. There are people who lie a lot out of politeness - relatively often. But there are also many people who hardly lie at all. Personally, I am also of the opinion that, apart from a few exceptional cases, you don't actually have to lie. Or that you can't answer unpleasant questions, for example.

To what extent a world without lies could function in a philosophical sense, I am not in a position to judge. What interests me is how I can get more information for negotiations and discussions and how I can recognise the whole thing. Lying weakens your own position in the long run and makes everything more complicated.

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