Did you eat the cookies? An interview with Petra Hendriks and Rineke Verbrugge
The collaboration between Professor in Semantics and Cognition Petra Hendriks and Professor in Logic and Cognition Rineke Verbrugge has already existed for more than a decade. This year, they joined forces again for a new exciting research topic: Lying. How do people learn to lie and why is lying so difficult, yet important? Let’s find out in this double interview, first published in the BCN Newsletter and written by Amélie la Roi.
In a double interview in which you participated exactly ten years ago, you talked about your plans for the future. Which of those plans have actually been realised?
RV: One of the things we wanted to investigate was whether the Theory of Mind that people have follows the rules predicted by logic and game theory. In my VICI project, which started in 2009, my group and I have studied this question from the perspectives of logic, cognitive psychology, child development, biology, and artificial intelligence. One of our major findings was that both adults and children do not at all reason as game theory predicts. For example, when playing a game in which you have to make several decisions, game theory predicts that the best strategy is to start at the endpoints and from there to reason back to see which decisions you have to make to get to the optimal solution. However, we found out that people actually start from the beginning and from there, they only think one or two steps ahead, which is a strategy that is much more similar to how we reason in everyday life. ‘As easy as possible, as complex as necessary’ is the principle that people seem to follow.
PH: This principle also applies to the findings of my VICI project, which started in 2007, because my group and I found that in language comprehension people only make additional reasoning steps when it is really necessary. We discovered this when investigating whether people use other people’s perspective to understand particular words and phrases in language that require Theory of Mind abilities. We examined this issue in healthy children and adults, but also in children with autism spectrum disorder (ASD), because these children are believed to have difficulties with Theory of Mind. One of our experiments studied the comprehension of pronouns such as ‘him’ and ‘her’. When interpreting a sentence such as ‘John hits him’, adults know that ‘him’ cannot refer to John, because if the speaker would have wanted to refer to John, he would have said ‘John hits himself’. This way of reasoning requires Theory of Mind, because you need to take into account the speaker’s choices when interpreting a sentence. Therefore, we predicted that children with better Theory of Mind skills also perform better when comprehending pronouns. This is indeed what we found. Coming back to Rineke’s principle ‘as easy as possible, as complex as necessary’, our pronoun finding is a nice example of a situation in which people really need to take an additional step of reasoning, because pronouns in themselves are ambiguous. If you do not consider the speaker’s options, you cannot know to whom a pronoun refers.
RV: We also found that not only the thoughts of someone else, but also the thoughts that someone else has about yet another person, which we call ‘second-order Theory of Mind’, appears to correlate very precisely with children’s understanding of recursion in language. An example of a sentence involving recursion is ‘Point to the mouse that hits the cat that eats another mouse’. At the same time as children around the age of 5 or 6 first acquire second-order Theory of Mind in false belief tasks, they also get better at understanding these types of complicated sentences.
Cognition clearly plays an important role in your research on language and logic. Ten years ago, you said that linguists were very hesitant about incorporating cognition in linguistic theory. Is this still the case?
PH: There really has been a change in linguistics. Ten years ago, linguistics still depended very heavily on formal models of language. The general idea was that linguistic competence should be distinguished from linguistic performance, and that cognition was part of performance. Competence was considered to be what linguistics was about, while cognition was an interfering factor that should be ignored if possible. Nowadays, linguistics has become much more interested in cognition, not only in the field of sentence processing, but also in first and second language acquisition, language and aging, and language attrition. So, cognition has definitely become more important in linguistics, also because evidence is accumulating that the linguistic capacities of individual speakers vary a lot and cognition may play an important part in explaining this variance.
RV: What you also see is that research is becoming more interdisciplinary. Linguists work together with neuroscientists, as well as with logicians. Ten years ago, researchers in the field of logic strongly believed in their theoretical models explaining how logic would work. If people in real life did something different from what their theoretical models predicted, then that was just too bad. In those times, logicians would not have thought about incorporating knowledge from a different field such as psychology or cognitive science to adjust or improve their models.
PH: Indeed, I think that ten years ago Rineke and I were in some sense pioneers, because there were not many other people who collaborated on a structural basis with researchers outside of their own fields. Nowadays, interdisciplinary research is promoted more and more. Of course, BCN is a nice example of this. BCN gives researchers the opportunity to meet researchers from other fields. In my opinion, meeting scientists from other disciplines is very valuable, because their questions can give you new insights in your own research and help you to improve it.
In January, you organised a workshop together with Hans van Ditmarsch about lying. What makes lying so interesting?
RV: What I think is intriguing about lying is that lying is not a cooperative process. In this, lying contrasts with other pragmatic principles that claim that language usually is cooperative and as a speaker you should stick to certain rules to keep your language cooperative. In lying, you don’t have these rules, so how does lying work? What constitutes a good lie and why is it so difficult for a recipient to distinguish a lie from the truth? Why is it so difficult for children to learn how to lie? Apparently, lying is a pretty complex process, so we are eager to know how this process works.
PH: Why lying intrigues me is also because most formal semantic models assume that if you know the meaning of a sentence, you also know under which conditions that sentence is true. However, if you look at how people use language in everyday life, you see that people actually don’t care so much about the truth of what they say and hear. In fact, if people would care more about the truth, we would be much better in telling whether someone told the truth or not. But apparently, language did not evolve to distinguish lies from the truth.
RV: Actually, the distinction between a lie and the truth really is not so clear, because some lies are even true. A speaker may want to make someone else believe in a statement that is in fact true but that the speaker believes to be false; we would still say that this speaker is lying. Or a speaker may say something that is strictly speaking true, but from which he knows that the hearer will probably conclude something false.
PH: For example, when someone asks you ‘Did you eat the cookies?’, you can say ‘I ate some cookies’. Saying ‘I ate some cookies’ implies that you ate some, but not all the cookies. However, ‘I ate some cookies’ can strictly speaking also mean that you ate all the cookies. So, if you actually ate all the cookies, but you say you ate some cookies, you suggest to the addressee that you did not eat all the cookies, without actually lying about not eating all the cookies. This shows that also linguistically, the difference between truth and lie is a difficult issue.
What are the ethical issues to take into account when doing research on lying?
RV: Well, if you look at the topic of lie detection, this research can easily be used for political goals, and I think that this is not always a good thing. However, investigating lying from the perspective of language and cognition can also promote positive things.
PH: Yes, in fact, telling lies and developing the ability to lie is an important human capacity. Some lies are even considered good in our society. For example, when your little niece just finished her school play and asks you how you liked it, you do not want to give the child a formal review of the quality of her school play. In this case, you just want to support the enthusiasm of your niece instead of telling her what you really think of her acting skills, because the truth may hurt your niece’s feelings. So in social interaction, it is sometimes good to bend the truth a little.
If you assume that cognition plays an important role in being able to lie, does that mean that intelligent people are better liars than less intelligent people?
RV: Haha, I don’t think so. At the workshop, we agreed that Hans, who co-organized the workshop with us, would need to tell three lies during the workshop. At the beginning of the workshop, we announced to all participants that at the end, we would ask them which one of us organizers they thought had told three lies. It turned out that Hans, who is a very smart person, found it really difficult to tell these lies. Not only did he need our advice about what would be good lies to tell, but he also found it difficult to decide when and how to tell these lies. In the end, a number of workshop participants were able to point to Hans as the ‘workshop liar’, but not because he told the lies that we advised him to tell, but just because he made some unintended mistakes when informing people about the program and other practical matters. So I think this is a funny example showing that being very smart does not necessarily imply that you are a good liar.
If in ten years from now I would interview you again, what would you like to have accomplished in these ten years?
RV: That is a very difficult question! One thing I would like to do is generalize my research on lying to the issue of truth and falsity. Today’s society is filled with false information and people have to deal with a lot of messages that are sent into society that are not true. I think it would be wonderful if we could teach people, from a young age into adulthood, how to better distinguish truth from falsity. This does not only concern the well-known fake news of U.S. President Donald Trump, but also to more general argumentation techniques that can be used to mislead people. For me, it is important to teach people how they can discover whether a source of information is reliable or not, as well as whether a piece of information is true or false.
PH: What intrigues me is the question how in communication people reach common understanding when using language. What are the dynamics of this process? How does this process develop in children? Lying is part of this dynamic process. When people lie, the knowledge that the people involved in the conversation have changes from being shared by all to being possessed by only one of the people in the conversation. In linguistics, there is a general trend that researchers move away from investigating what happens in the head of a single individual to studying what happens to people when they interact. I think it is important to see language as a system that is used by people in interaction and investigate which factors influence this dynamic language system.
 Hendriks, P. & Verbrugge, L.C. (2006). Mind reading en pragmatisch redeneren voor gevorderden (K. Zondervan, Interviewer). De Connectie, 5(1). Retrieved from http://www.deconnectie.com/docs/vorige_connecties/pdfs_van_artikelen/c05-play/kzondervan_c5_pg8-10.pdf