Eurasian jays (Garrulus glandarius) conceal caches from onlookers.

Animals that cache food risk having their stored food pilfered by conspecifics. Previous research has shown that a number of food-caching species of corvid use strategies that decrease the probability of conspecifics pilfering their caches. In this experiment, we investigated whether Eurasian jays (Garrulus glandarius) would choose between caching behind an opaque and caching behind a transparent barrier whilst being observed by a conspecific. If caching in out-of-sight locations is a strategy to prevent conspecifics from pilfering these caches, then the jays should place a greater proportion of caches behind the opaque barrier when being observed than when caching in private. In accordance with this prediction, jays cached a greater proportion of food behind the opaque barrier when they were observed than when they cached in private. These results suggest that Eurasian jays may opt to cache in out-of-view locations to reduce the likelihood of conspecifics pilfering their caches

Error rate on the director's task is influenced by the need to take another's perspective but not the type of perspective.

Adults are prone to responding erroneously to another's instructions based on what they themselves see and not what the other person sees. Previous studies have indicated that in instruction-following tasks participants make more errors when required to infer another's perspective than when following a rule. These inference-induced errors may occur because the inference process itself is error-prone or because they are a side effect of the inference process. Crucially, if the inference process is error-prone, then higher error rates should be found when the perspective to be inferred is more complex. Here, we found that participants were no more error-prone when they had to judge how an item appeared (Level 2 perspective-taking) than when they had to judge whether an item could or could not be seen (Level 1 perspective-taking). However, participants were more error-prone in the perspective-taking variants of the task than in a version that only required them to follow a rule. These results suggest that having to represent another's perspective induces errors when following their instructions but that error rates are not directly linked to errors in inferring another's perspective

Desire-state attribution: Benefits of a novel paradigm using the food-sharing behavior of Eurasian jays (Garrulus glandarius).

In recent years, we have investigated the possibility that Eurasian jay food sharing might rely on desire-state attribution. The female's desire for a particular type of food can be decreased by sating her on it (specific satiety) and the food sharing paradigm can be used to test whether the male's sharing pattern reflects the female's current desire. Our previous findings show that the male shares the food that the female currently wants. Here, we consider 3 simpler mechanisms that might explain the male's behavior: behavior reading, lack of self-other differentiation and behavioral rules. We illustrate how we have already addressed these issues and how our food sharing paradigm can be further adapted to answer outstanding questions. The flexibility with which the food sharing paradigm can be applied to rule out alternative mechanisms makes it a useful tool to study desire-state attribution in jays and other species that share food

Caching at a distance: a cache protection strategy in Eurasian jays.

A fundamental question about the complexity of corvid social cognition is whether behaviours exhibited when caching in front of potential pilferers represent specific attempts to prevent cache loss (cache protection hypothesis) or whether they are by-products of other behaviours (by-product hypothesis). Here, we demonstrate that Eurasian jays preferentially cache at a distance when observed by conspecifics. This preference for a 'far' location could be either a by-product of a general preference for caching at that specific location regardless of the risk of cache loss or a by-product of a general preference to be far away from conspecifics due to low intra-species tolerance. Critically, we found that neither by-product account explains the jays' behaviour: the preference for the 'far' location was not shown when caching in private or when eating in front of a conspecific. In line with the cache protection hypothesis we found that jays preferred the distant location only when caching in front of a conspecific. Thus, it seems likely that for Eurasian jays, caching at a distance from an observer is a specific cache protection strategy.We thank the Leverhulme Trust and the Grindley Fund for financial support

Can male Eurasian jays disengage from their own current desire to feed the female what she wants?

Humans' predictions of another person's behaviour are regularly influenced by what they themselves might know or want. In a previous study, we found that male Eurasian jays (Garrulus glandarius) could cater for their female partner's current desire when sharing food with her. Here, we tested the extent to which the males' decisions are influenced by their own current desire. When the males' and female's desires matched, males correctly shared the food that was desired by both. When the female's desire differed from their own, the males' decisions were not entirely driven by their own desires, suggesting that males also took the female's desire into account. Thus, the male jays' decisions about their mates' desires are partially biased by their own desire and might be based upon similar processes as those found in humans

Egocentric bias across mental and non-mental representations in the Sandbox Task.

In the Sandbox Task, participants indicate where a protagonist who has a false belief about the location of an object will look for that object in a trough filled with a substrate that conceals the hidden object's location. Previous findings that participants tend to indicate a location closer to where they themselves know the object to be located have been interpreted as evidence of egocentric bias when attributing mental states to others. We tested the assumption that such biases occur as a result of reasoning about mental states specifically. We found that participants showed more egocentric bias when reasoning from a protagonist's false belief than from their own memory, but found equivalent levels of bias when they were asked to indicate where a false film would depict the object as when they were asked about a protagonist's false belief. Our findings suggest that that egocentric biases found in adult false belief tasks are more likely due to a general difficulty with reasoning about false representations than a specialised difficulty with reasoning about false mental states.This work was supported by an ESRC grant (ES/M008460/1) (SS, RL and NC) and by a Leverhulme grant (RPG-2014-353) (EL and NC)

Experimenter Expectancy Bias Does Not Explain Eurasian Jays' (Garrulus glandarius) Performance in a Desire-State Attribution Task

Male Eurasian jays have been found to adjust the type of food they share with their female partner after seeing her eat one type of food to satiety. One interpretation of this behavior is that the male encoded the female’s decreased desire for the food she was sated on, and adjusted his behavior accordingly. However, in these studies, the male’s actions were scored by experimenters who knew on which food the female was sated. Thus, it is possible that the experimenters’ expectations (sub-consciously) affected their behavior during tests that, in turn, inadvertently could have influenced the males’ actions. Here, we repeated the original test with an experimenter who was blind to the food on which the female was sated. This procedure yielded the same results as the original studies: the male shared food with the female that was in line with her current desire. Thus, our results rule out the possibility that the Eurasian jay males’ actions in the food sharing task could be explained by the effects of an experimenter expectancy bias

Teorija uma: pregled suvremenih empirijskih rezultata i glavnih teorijskih objašnjenja

Theory of Mind is the ability to attribute mental states to others. Until around 20 years ago most evidence pointed to Theory of Mind being a cognitively demanding skill that likely develops at around 4 years of age. However, there is a growing body of literature based on experiments that do not rely on verbal measures that suggests that Theory of Mind-like abilities may occur outside of cognitive control and in infants as young as 9 months. This review discusses the three main types of account that have been proposed as explanations of these new results. Furthermore, it highlights the evidence supporting and contrasting each type of account. There is currently no single account that provides an uncontested explanation of all current data, however, one of the reasons for this is that there is a degree of ambiguity in the predictions and interpretations of each of the accounts making it challenging for any set of experiments to refute an account. Consequently, the future of research on Theory of Mind appears to rely on these accounts producing less ambiguous predictions that cannot be insulated from refutation.Teorija uma je sposobnost pripisivanja mentalnih stanja drugima. Do prije otprilike 20 godina empirijska istraživanja upućivala su na to da je teorija uma kognitivno zahtjevna sposobnost koja se razvija oko četvrte godine života. Međutim, sve veći broj istraživanja koja koriste zadatke koji ne zahtijevaju verbalne odgovore upućuje na to da sposobnost koja nalikuje na teoriju uma postoji i izvan kognitivne kontrole te da je pokazuju već i djeca stara devet mjeseci. Ovaj pregledni rad predstavit će tri glavna tipa teorija koje pokušavaju objasniti te novije empirijske rezultate i raspraviti o njima. Nadalje, u radu će biti istaknuti empirijski nalazi koji idu u prilog svakoj od tih teorija ili je opovrgavaju. Iako postoje prijedlozi za kritične eksperimente koji bi trebali moćinapraviti razliku između teorija, trenutačno ti prijedlozi još nisu dovoljno korisni za te svrhe jer se podatci koji bi se mogli dobiti takvim eksperimentima mogu u različitim teorijama različito interpretirati. Stoga je važno da se budući rad o teoriji uma fokusira na uklanjanje dvosmislenosti u predviđanjima i interpretacijama svake od teorija

Can male Eurasian jays disengage from their own current desire to feed the female what she wants?

Humans' predictions of another person's behaviour are regularly influenced by what they themselves might know or want. In a previous study, we found that male Eurasian jays (Garrulus glandarius) could cater for their female partner's current desire when sharing food with her. Here, we tested the extent to which the males' decisions are influenced by their own current desire. When the males' and female's desires matched, males correctly shared the food that was desired by both. When the female's desire differed from their own, the males' decisions were not entirely driven by their own desires, suggesting that males also took the female's desire into account. Thus, the male jays' decisions about their mates' desires are partially biased by their own desire and might be based upon similar processes as those found in humans

The unreliability of egocentric bias across self-other and memory-belief distinctions in the Sandbox Task.

Humans are often considered egocentric creatures, particularly (and ironically) when we are supposed to take another person's perspective over our own (i.e. when we use our theory of mind). We investigated the underlying causes of this phenomenon. We gave young adult participants a false belief task (Sandbox Task) in which objects were first hidden at one location by a protagonist and then moved to a second location within the same space but in the protagonist's absence. Participants were asked to indicate either where the protagonist remembered the item to be (reasoning about another's memory), believed it to be (reasoning about another's false belief), or where the protagonist would look for it (action prediction of another based on false belief). The distance away from Location A (the original one) towards Location B (the new location) was our measure of egocentric bias. We found no evidence that egocentric bias varied according to reasoning type, and no evidence that participants actually were more biased when reasoning about another person than when simply recalling the first location from memory. We conclude that the Sandbox Task paradigm may not be sensitive enough to draw out consistent effects related to mental state reasoning in young adults.This work was supported by an ESRC grant (ES/M008460/1: PI = NSC) (and by a Leverhulme grant (RPG-2014-353: PI = NSC) (EL and NSC)