Christian Nawroth is an animal cognition researcher at the Queen Mary University of London. He specializes in studying the cognitive abilities of farm animals, and applying his findings in ways that can help improve their welfare and treatment. If you’d like to learn more about his research and publications, please visit his website.
Q: Your research focuses on the cognition of farm animals, particularly goats and pigs. What led you to study these animals?
A: Most cognition studies on non-human animals focus on our closest living relatives, primates in general and great apes in particular, and more recently, in terms of convergent cognitive evolution, on corvids and dogs. Compared with the amount of studies conducted on the aforementioned species – and despite noteworthy examples – studies on the basic cognitive capabilities of farm animals are underrepresented.
Keeping in mind that the latter are kept in huge numbers in industrial production systems worldwide, it is of great importance to provide them with welfare-friendly systems. To accomplish this, it is not only necessary to reduce bad welfare, but also to foster good welfare. Thus, we have to understand how farm animals experience the world – which can hugely differ from our own experience.
During my undergraduate studies, I gained first-hand experience in conducting cognitive tests with great apes at the Max Planck Institute for Evolutionary Anthropology.1 While I was searching for a PhD position later on, I happily agreed when I was offered to investigate the behavior of farm animals (domestic pigs, dwarf goats, and sheep in particular) at the University of Halle,2 Germany. Here, I wanted to gain a better understanding of how these animals mentally represent their physical and social environment. To achieve this, I used cognitive test paradigms from recent comparative psychological research in primates and dogs and modified them to the behavioural needs and constraints of the species tested.
Q: Recently you and colleagues published a paper on “object permanence” in dwarf goats. Can you tell us what that means, and what the results of your study are?
A: Briefly, object permanence is the notion that objects continue to exist even when they are out of an observer’s sight. The concept goes back to developmental psychologist Jean Piaget, who initially developed it in the 1950’s. In the Piagetian classification, there are six stages within the sensorimotor period during which sensorimotor intelligence in infants develops. Although some researchers disagree with the temporal onset of specific stages in human development, the progression in the specific stages can also be observed in non-human animals, e.g. birds. Most studies on object permanence on non-human mammals focused on primates, and in particular great apes. A few studies were also conducted on dogs and cats. While great apes and some monkey species show evidence of the highest stage of object permanence, other non-primate mammals performed rather poorly in the more complex tasks.
In the current study3, we involved dwarf goats (in collaboration with the FBN in Dummerstorf4) in a series of experiments in which the goats were separated from the experimenter and a reward by a grate. They had the opportunity to choose through the grate between two cups while only one of them was baited.
Initially, the goats saw the baiting procedure and that subsequently the experimenter moved the cups, changing their position. To make a correct choice and thus obtain the reward, the goats would (1) have to keep in mind a mental representation of the hidden reward, (2) have to be able to follow the trajectory of the cup hiding the reward during the movement and (3) have to restrain themselves from choosing the location where they have last seen the reward.
Although other factors, such as the movement and the specific location of the baited cup, influenced the goats´ decision making, the results suggest that individual dwarf goats were able to keep track of hidden objects. These results are quite surprising, as dogs and cats fail in this so-called transposition task and continue to search for the hidden reward at the location where they have last seen it.
Q: You also studied object permanence in pigs. How do their abilities compare to goats?
A: It is always difficult to make specific comparisons, in particular when the test settings are not identical – as it was in the case of these two studies.5 The pigs we used in the other study were few in number and quite young – and may therefore have been too young to show their full potential in the task. However, we found that the pigs were able to follow simple visible displacements of a food reward, but not complex transposition like the goats.
One interesting point that we observed was that the pigs were much more interested in the grate that separated them from the reward and the experimenter than the goats – which fits perfectly with their olfactory and haptic/tactile exploration style. However, this distraction may have also prevented them in performing better in the tasks.
Q: Pigs seem to be good at finding objects in other ways though. For instance, pigs can find hidden food when that food’s location is revealed in a mirror. This seems to require some pretty high-level assessment abilities. What do you think the implications are of such findings?
A recent study6 failed to replicate these initial findings. However, as the absence of evidence is not evidence of absence, more work has to be done here to show a more complete picture. Nonetheless, pigs have quite sophisticated socio-cognitive skills. For example, they will start to exploit the knowledge of subordinate pigs.7 In turn, these subordinates start to develop counter-exploitation strategies.8
There is also some evidence that pigs might be able to take the visual perspective of other pigs.9 This tells us that pigs’ social systems are most probably more complex than previously thought. One of the implications is that we definitely have to re-evaluate how we treat pigs under production conditions and what we can do to provide them with opportunities to express complex social behaviour. In my opinion, a better understanding of how farm animals comprehend their physical and social environment will help to better understand their needs and will ultimately lead to an improvement in animal welfare in the long term.
Q: What would you count as your most surprising findings while researching farm animals?
A: There were actually two. The first was when we discovered that even very young pigs were able to follow the head direction10 of a human as a cue to find food in a choice task – something that was shown for dogs, but no other domesticated animal before.
The second surprising finding was that the goats we‘ve tested in a food anticipation paradigm stopped to show active anticipation behaviour (i.e. nervously tripping in front of the grate that separated them from the reward) after a short period of time and engaged in a behaviour we would describe best as standing alert. Here, the goats literally stared motionless at the experimenter and the experimental setup. More surprisingly, the expression of this standing alert behaviour was sensitive to the attention the human was paying towards the goat.11
Q: Interesting! In what way did the human’s attention influence the goat’s standing alert behavior?
The goats only showed an increase in standing alert behaviour when the experimenter was present in the adjacent compartment but was not paying attention to the subject – either by turning his head away (Video 1) or turning his back towards the goat. In comparison, standing alert behaviour was decreased when the experimenter was looking at the goat (+ high levels active anticipation behaviour; Video 2) or when the experimenter had left the compartment (+ very low levels of active anticipation behaviour).
Q: Another past study you participated in assessed the risk-taking strategies of great apes when making decisions about food rewards. It was found that some species tend to take more risks than other species, by, for example, foregoing a small guaranteed reward for the possibility of a big reward. Why is that?
A: In this study,12 we presented all great ape species with a safe, but small reward and a risky, but large reward. In the task, gorillas and bonobos opted out for the safe option more frequently compared to the chimpanzees and orang-utans – which continued to choose the risky option.
Differences in the natural ecology of a species might likely explain some of the differences in their risk preferences. While all great ape species eat ripe fruit when it is available, chimpanzees are ripe fruit specialists, which means that in times of low fruit abundance they continue searching for fruit – which can be a risky endeavour. In contrast, bonobos under these circumstances shift to consuming higher levels of leaves, young shoots, and stem tips – highly consistent and abundant food sources. This might explain why e.g. chimpanzees appear to be more risk prone on foraging tasks than bonobos.
Q: Can you tell us a bit about any research projects you are currently conducting?
A: I recently got funded with a stipend from the German Research Foundation to study complex human-animal interactions in goats at Queen Mary, University of London13 (hosted by Alan McElligott14). Here, I will test goats at a goat sanctuary (Buttercups Sanctuary15) in their ability to differentiate and memorize human handlers. In addition, I want to investigate what particular kind of information goats can extract from humans and how they use this information in their decision-making processes.
Q: What was one of your most incredible moments in the field?
A: After some weeks of testing, the pigs in my experiments started to ‘behave‘ – without explicitly training them to do so. In particular, they started to wait until a test trial was set up before entering the test area – something that contradicted their initial eagerness to approach the food containers placed in the area. It was fascinating to see how they were struggling with themselves to stay where they are and not to run straight into the area – likely receiving nothing at all as the experimenter was not ready at this point.
Q: What fact about farm animal cognition or behavior do you think is most important for the world to know?
A: This is simple: farm animals are sentient beings and have sophisticated cognitive capacities to deal with their physical and social environment. We shouldn’t treat them with less care than we want to have treated our pet animals.
This interview was conducted by Amanda Pachniewska, founder & editor of AnimalCognition.org
1 – Max Planck Institute for Evolutionary Anthropology
2 – University of Halle
3 – Christian Nawrotha, Eberhard von Borella, Jan Langbeinb
Object permanence in the dwarf goat (Capra aegagrus hircus): Perseveration errors and the tracking of complex movements of hidden objects
Applied Animal Behaviour Science
4 – Leibniz Institute for Farm Animal Biology (FBN)
5 – Christian Nawroth, Mirjam Ebersbach and Eberhard von Borell
A note on pigs’ knowledge of hidden objects
6 – Elise T. Gieling, et al.
Lack of mirror use by pigs to locate food
Applied Animal Behaviour Science
7 – Suzanne Held, et al.
Social tactics of pigs in a competitive foraging task: the ‘informed forager’ paradigm
8 – Suzanne Held, et al.
Foraging pigs alter their behavior in response to exploitation
9 – Suzanne Held, et al.
Behaviour of domestic pigs in a visual perspective taking task
10 – Christian Nawroth, et al.
Juvenile domestic pigs (Sus scrofa domestica) use human-given cues in an object choice task
11 – Christian Nawroth, et al.
‘Goats that stare at men’ : dwarf goats alter their behaviour in response to human head orientation, but do not spontaneously use head direction as a cue in a food related context
12 – Daniel B. M. Haun, Christian Nawroth, Joseph Call
Great Apes’ Risk-Taking Strategies in a Decision Making Task
13 – Queen Mary University of London
14 – Alan McElligott
15 – Buttercups Sanctuary for Goats