‘Perhaps the difference between us and other species is that we have taken it to the extremes’

When did you meet your first (non-human) ape?
Up close and personal, my first encounter took place at the Barcelona Zoo while I was a high-school student. I spent the summer of my first high-school year doing a research project there, and I absolutely loved it. During that time I met one of the staff at the zoo nursery who introduce me to Kena and Bindung, the two infant gorillas who were being raised there. They were tiny and seemed extremely delicate and fragile, just like newborn human infants. I was not prepared for it given how large and imposing the adults are.

Are some apes smarter than others?
Yes, or at least they are smarter than others based on the instruments that we use to measure their intelligence. But it is also the case that different apes have different intellectual strengths. Some are quite good with problem-solving tasks (puzzle boxes) while others are socially savvy (theory of mind tasks). One has also to consider that the reason some individuals do well on multiple tasks is because they are highly motivated to obtain extra fruit treats (by the way, we never food- or water-deprive any of the apes that we test) or they simply like the challenge. We had cases of some apes solving a task for a highly valued treat and once she got it, gave it back to us or she did not end up eating it.

Is there much to be learned from exceptionally able animals, or are they just outliers and cheap tricks?
The fun part, and what constitutes an integral part of our work, is trying to distinguish 'cheap tricks' as you called them, from the operation of other cognitive processes. In other words, our work usually begins with an initial observation. If you want to know why an animal does that, or more precisely what stimuli control their behaviour, you need to pose a set of hypotheses and test them. This is exactly the approach that we took with Rico, the border collie that knew words for hundreds of objects. One could have dismissed it as a case like 'Clever Hans', the 'counting' horse, but Juliane Kaminski, Julia Fischer and I decided to test whether this was the case. As it turns out, it was not a case of Clever Hans. Rico knew the labels for those objects and, furthermore, we were able to document that he used an inferential process to learn new labels for new objects. Quite far removed from a 'cheap trick', I would say.

Tell me about Dognition. It seems like a neat exercise in public engagement and 'citizen science'.
It is. Dognition is a company founded by Brian Hare and Vanessa Woods. It provides dog owners with a test battery aimed at assessing the cognitive abilities of their dogs using the same methods that scientists use to conduct their studies. It accomplishes two main missions – first, it brings to the general public a wealth of practical and theoretical knowledge that has been accumulated in recent years with regard to canine intelligence. More importantly, it makes dog owners integral players in the scientific endeavour because they collect that data that Dognition then collates and is later used to produce new scientific knowledge. An excellent example of citizen science with clear benefits both for the general public and the scientists. Note that dog owners are keen observers of their pets, and quite often we have used their very valuable observations – Rico's case, which I mentioned earlier, is a good example of that, to launch the next research question.

I guess there's always a risk of anthropomorphism?
Not if we rigorously test our hypotheses against hard data. Quite often, the hypotheses that would raise no eyebrows turn out to be unsupported by the evidence, but historically, there is a widespread practice of uncritically accepting so-called low-level hypotheses without even bothering to test them. Even a cursory reading of classics like Lloyd Morgan, who is often portrayed as someone in favour of low-level explanations, would show that he was actually quite open-minded (sceptical yes, but open-minded) regarding high-level explanations. I tell my students that they should get their inspiration from anywhere they can, provided they test those ideas rigorously and consider alternative explanations and the available evidence as a whole.

I think that entertaining some daring ideas and embarking on high-risk projects can be quite healthy. The case of theory of mind is an instructive one in this regard. Many of the hypotheses that were postulated to explain the behaviour of non-human animals in the early 1990s are no longer viable due to the evidence that has accumulated in the last three decades. Have we answered all the questions regarding ToM in non-human animals? Of course not, but we have made a lot of progress towards consolidating the idea that although those species might not be as sophisticated as humans in some regards, their behaviour is not just based on 'cheap tricks' and simple learning mechanisms.

Over time, are we finding that humans are less and less unique? Is there much left that separates us?
I think so, or at least, we can find what we think are precursors or building blocks of some of the abilities that have been traditionally considered uniquely human.

If we're not unique, then why don't other primates talk?
As far as I can tell, there is no silver bullet that explains the difference between them and us. I think that there are multiple cognitive and motivational changes that have taken place in the last seven million years since we shared a common ancestor with the other great apes. One such change is the motivational aspect to communicate. Humans often engage in conversation for the sake of it. I think that primates use communication in a more instrumental manner, as a means to an end, not as an end in itself. With regard to cognitive changes, displaced reference has traditionally been considered a uniquely human feature, although recently we found that apes without any sort of language training (e.g. sign language) can also refer to absent entities provided the setting includes a human interlocutor. One of our current goals is to find out whether displaced reference can also occur even among conspecifics without any human intervention.

Does working with non-human primates make you wonder where it all went wrong for humans? Having said that, I saw the film Jane recently, about the anthropologist Jane Goodall, and I was struck by the bit surrounding chimp warfare and her reaction to that.
I do not think that 'it all went wrong for humans'. We are not angels, but we are not demons either. Our species is capable of the kindest acts and the most terrible ones. We are not good or bad all the time, we are a puzzling mix of both.

And is that the same in the species you study?
Probably, if you consider the available evidence and the different positions currently being discussed in the literature. Perhaps the difference between us and other species is that we have taken it to the extremes.

What's the status of primate research these days?
There are a number of scholars in the UK studying primate behaviour and cognition in the laboratory and the field. From that perspective, I think that things are quite healthy. Undergraduate students and postgraduate students also show considerable interest in this subject, which is good because sufficient student numbers combined with other considerations is what contributes to keep a field healthy. Perhaps one of the changes that has occurred in recent years is that researchers from Universities and Research Centres are collaborating more closely with zoos around the world. We have examples in the US, Germany and Sweden. In the UK there is the Living Links and Budongo Research Unit consortium based at the Edinburgh Zoo, where visitors can see researchers from several Scottish universities at work getting precious data that they cannot obtain elsewhere. I think that the university–zoo collaboration is an excellent model that benefits all parties involved, including the general public who can observe scientists at work, thus helping us educate not just the students that we see in our lectures but the general public, beginning with the schoolchildren when they visit us there.

What makes what you do different from what a biologist does when they study animals and animal behaviour?
Less than what many people may suspect. Some comparative psychologists are virtually indistinguishable from biologists. They study the same species, use the same methods and entertain the same theories as students of animal behaviour. In fact, some comparative psychologists are closer to biologists than to some clinical, educational or social psychologists, just to name a few of our specialties. But if you press me, I think that what distinguishes us from biologists is our focus on psychological processes including cognition (and learning), motivation and emotion. Some biologists also study them, but in general, I think that we spend more time thinking about these issues than biologists.

What next for you?  
I am excited about several things. I am preparing to teach a module on comparative psychology that combines neuroscience, cognition and behaviour that I hope will provide the students with a holistic view of my field. The course will also have a practical component that I hope the students will enjoy. We have recently started to work with the chimpanzees at the newly opened Budongo Research Unit in Edinburgh Zoo – this state-of-the-art research facility of the University of St Andrews will allow us to conduct cutting-edge research on chimpanzee cognition and behaviour. In the coming months we will be investigating how chimpanzees work together to solve a task using touch screens and how they conceive the stimuli that they see on the screen – do they see them linked somehow with their referents in the real world or are the virtual and real worlds kept completely separate? This is an example of a high-risk project that poses an extremely exciting question that may contribute to shape how we conceive other non-human minds.

Do you have animals in your house? If you could have any 'pet', practical considerations aside, what would it be and why?
We do not currently have any pets at home, but I really enjoy watching the creatures that roam our garden day and night. I would pick a Labrador retriever as a pet because they are great companions and I think that it would enjoy running around in our garden.