I hope it’s not too arrogant to say that our corvid research has been at the forefront of revolutionising our understanding of avian intelligence. Compared to the old image of dumb birds, we now know that corvids and parrots are as smart as apes. This view has changed because a suite of lab studies, including our own, have built upon the birds’ natural abilities, such as caching, tool-use and cooperation, to design ecologically valid experiments focusing on the relationship between what birds do naturally, such as hiding food, and the psychological processes, such as memory, underlying this behaviour. For example, Nicky Clayton pioneered studies on the complex memories of western scrub-jays with Tony Dickinson, discovering for the first time that a non-human animal could remember detailed information about specific events in their past, which they termed episodic-like memory. After observing the jays’ behaviour on the campus of UC Davis where we met, and thinking about the implications of such caching behaviour to social cognition and theory of mind, we designed a series of experiments to determine whether the jays made caching decisions based on who was watching when they cached, and whether they did anything to reduce the chance of pilfering when prying eyes had left the scene. We found that cachers moved their food stashes around after a potential thief had left, moving them to new places which the thief would have no knowledge. Perhaps most surprisingly, only birds that had experience of being thieves themselves did this, suggesting that it takes a thief to know a thief. We called this experience projection. An individual simulates another’s mind by thinking about their own experiences in a similar situation, something akin to putting yourself in another’s shoes. This had yet to be demonstrated in any animal. We followed this original finding with a series of experiments performed by Nicky’s PhD student, Joanna Dally, looking at the jays’ social cognition. Were the jays choosing the more protective locations to cache in, such as behind a barrier, as far from an observer as possible or in the dark? Would the jays prefer to cache in from of their partner or a subordinate rather than a stranger or dominant?Would the jays discriminate observers based on what information they had previously seen (i.e. what knowledge they may or may not have possessed)? The jays made all the most logical choices.
At the same time, Nicky and I decided we needed to establish a colony of British corvids. Nicky had brought her colony of scrub-jays over with us from California when we moved to Cambridge in 2000, but they were not exactly easy to replace if birds got sick or we needed to expand the colony. We therefore developed a colony of caching rooks and non-caching jackdaws for comparative studies. In 2002, we were able to procure a number of very young rook and jackdaw chicks from the wild before their eyes had opened (and so hadn’t formed any attachments), hand raised them until they became independent and used them to establish a captive group of rooks and jackdaws in the Sub-Department of Animal Behaviour. We immediately started recording their social relationships, investigating their food sharing (with postdoc Selvino de Kort), and longer-term studies on cooperative behaviour and eventually physical cognition, developing a series of novel tasks, such as the two trap tube task (with PhD student Amanda Seed and postdoc Sabine Tebbich), as well as the collapsible platform, Aesops’ fable and peephole tasks (with PhD student Chris Bird). Finally, my PhD student Auguste von Bayern developed a colony of jackdaws in Bavaria, and completed a series of studies on jackdaw social cognition, finding that they could use human social cues, such as eye gaze to locate hidden food. These studies have revealed more abilities that were assumed to either be primate specialisations or even uniquely human, such as third-party post-conflict affiliation (consolation), cooperative problem-solving, causal reasoning, mental attribution and possibly even insightful behaviour.
A few years ago, I moved to Queen Mary University of London, but because of its location in the east end of London, I could not establish a large enough corvid facility, so decided to focus my attention onto parrots instead. After a long time period of research into which species we should work with, we decided on black-headed caiques and red-shouldered (Hahn’s) macaws. I was lucky enough to take on a talented student, Jayden van Horik, who single-handedly set up the new lab and started working with the birds. We are in the process of publishing the various studies Jayden completed with them, such as means-ends reasoning, reversal learning and self-control, although our findings re limited because we only had 4 birds for each species. Unfortunately, after Jayden completed his PhD and I became seriously ill, I could no longer maintain the parrot facility, but I’d like to work with parrots again, possibly in a zoo environment.
Primate Social Neuroscience
I started my professional research career, not with birds, but with primates. I say professional, because my first research project as an undergraduate, was on the avian brain! My PhD work in St Andrews with Dave Perrett was on the neurobiology of primate social behaviour, recording from neutrons in the monkey temporal cortex (superior temporal polysensory area) in response to social stimuli, such as faces, intentional body movements and eye gaze. During this time, I was also the first to demonstrate that monkeys could follow eye gaze cues to objects. Up to that time, it was assumed that despite monkey brains containing neurons responsive to eye gaze direction, monkeys did not appear to use this information to learn about objects in the world – i.e. they could not use another’s gaze to locate hidden objects. This seemed counterintuitive, but was the finding of a number of previous studies. However, by using other monkeys as stimuli, and recording our subjects’ eye movements, rather than ‘asking’ the monkeys to act upon the gaze cues they perceived, we found that they were more likely to look at the same object another monkeys was looking at, rather than a distractor object that wasn’t the object of the other monkey’s attention. There have now been dozens of studies that have confirmed this result.
After my PhD, I moved to UCDavis to work with David Amaral, John Capitanio, Bill Mason and Sally Mendoza on a project investigating the role of the amygdala in primate social cognition. Previous studies had used crude ablation techniques to destroy the amygdala of monkeys and then measured the response of this damage on the monkeys’ social interactions. We wanted to see whether modern, more sophisticated and subtle lesion techniques, as well as more complex behavioural techniques would tell a different story. We believed that the amygdala played an important role in the aetiology of various psychopathological disorders, so our ultimate aim was to create a primate model of autism. This turned out to be a little naive, as the effect of the lesions was not to create socially withdrawn monkeys, but gregarious party animals! Rather than remain at a safe distance from strangers like normal adult male rhesus monkeys, our monkeys approached, sat close to and even groomed other monkeys they had never met before. This social disinhibition seemed to have a calming effect on the normal monkeys, as they displayed little aggression and even interacted with their social weirdos. This finding was also reported in human patients with amygdala damage, and the amygdala displays increased activation when presented with untrustworthy faces, so the monkey work had direct relevance to neurobiology of human social cognition. Amaral’s team has moved this research into new areas and the results are likely to have far reaching implications for a range of psychopathological disorders of sociality.
However, ultimately this work was not for me. Although I remain convinced that a lot of invasive animal research is still vital for understanding human and animal disease, as well as the normal function of the brain, it’s not work that I want to do again.