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. 2021 Sep 10:10:e69647.
doi: 10.7554/eLife.69647.

Little evidence that Eurasian jays protect their caches by responding to cues about a conspecific's desire and visual perspective

Piero Amodio  1   2 , Benjamin G Farrar  1   3 , Christopher Krupenye  4   5 , Ljerka Ostojić  1   6 , Nicola S Clayton  1
Affiliations

Little evidence that Eurasian jays protect their caches by responding to cues about a conspecific's desire and visual perspective

Piero Amodio et al. Elife. .

Abstract

Eurasian jays have been reported to protect their caches by responding to cues about either the visual perspective or current desire of an observing conspecific, similarly to other corvids. Here, we used established paradigms to test whether these birds can - like humans - integrate multiple cues about different mental states and perform an optimal response accordingly. Across five experiments, which also include replications of previous work, we found little evidence that our jays adjusted their caching behaviour in line with the visual perspective and current desire of another agent, neither by integrating these social cues nor by responding to only one type of cue independently. These results raise questions about the reliability of the previously reported effects and highlight several key issues affecting reliability in comparative cognition research.

Keywords: Eurasian jay; corvids; desires; ecology; perspective; replication; theory of mind.

Plain language summary

Eurasian jays, Garrulus glandarius, are members of the crow family. These large-brained birds hide food when it is abundant, and eat it later, when it is scarce. Previous studies have found that jays avoid theft by other jays by carefully deciding what food to hide, and where. In one study, they preferred to hide their food behind an opaque barrier, rather than a transparent one, when another jay was watching. In a second study, they preferred to hide food that the watching jay had already eaten enough of, and thus did not want. These studies suggest that jays have flexible cognitive skills when it comes to protecting their food. They respond to whether a potential thief can see their hiding place and to how much a thief might want the food they are stashing. The next question is, can Eurasian jays combine these two pieces of information? For example, if a jay has two types of food they could hide when another jay is present, but only has one place to hide them (either in view or out-of-view of the other jay), does the first jay prefer to stash the food that the second jay has already eaten, and therefore does not want anymore, only when the hiding place is visible to second jay? To find out, Amodio et al. watched Eurasian jays hiding macadamia nuts or peanuts in the presence of another jay. In the first setup, jays were given one food to hide and two possible hiding places, one opaque and one transparent, while being watched by a jay that had either had its fill of the food, or not tried it. In the second setup, jays were given both foods to hide, but only had one place to hide them (either transparent or opaque); while being watched by a jay that had eaten enough of one of the foods. Contrary to expectations, the jays did not seem to be able to combine the information about what the other jay could see and what it had been eating. In fact, they seemed unable to respond to either piece of information. When Amodio et al. repeated the original experiments, the jays did not seem to prefer to hide food out of sight, or to hide food that the watcher had already eaten. These results raise questions about the repeatability of experiments on food hiding strategies in birds of the crow family. It suggests that previous findings should be further investigated, potentially to identify important factors that might affect the repeatability of food-hiding tactics. Repeating the experiments may show how best to investigate behavioural patterns in jays in the future.

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Conflict of interest statement

PA, BF, CK, LO, NC No competing interests declared

Figures

Figure 1.
Figure 1.. Methods and results of Experiment 1.
Top panel: Top-view schematic representation of the set-up and procedure used in Experiment 1. In the familiarisation (left), the cacher bird received two trials, one in which the caching tray was placed near the opaque arm of the barrier, and one in which the tray was placed near the clear arm of the barrier. In the test, trials were composed by a pre-feeding phase (middle) and a caching phase (right). The cacher bird received two trials that differed in the type of food that was provided to the observer bird in the pre-feeding phase. In one trial (Different Food condition), the food provided to the observer in the pre-feeding phase differed from the food the cacher bird could subsequently cache. In the other trial (Same Food condition), the food provided to the observer in the pre-feeding phase was the same as the food the cacher bird could subsequently cache. In the pre-feeding phase of both trials, the cacher bird was provided with a handful of maintenance diet (md). Note that, for explanatory purposes, the scheme shows the cacher as being provided with peanuts (P) in the familiarisation and in the caching phase of the two test trials. However, in the experiment, cacher birds were randomly assigned to one type of food (either peanuts or macadamia nuts), which was used consistently in the familiarisation and in the caching phase of all trials. Bottom Panel: Box and whisker plots of data in Experiment 1. The plot on the left shows the difference in the number of items cached in the out-of-view tray minus the number of items cached in the in-view tray in the two experimental conditions. The plot on the right shows the proportion of items cached in the out-of-view tray (out of total caches) in the two experimental conditions.
Figure 2.
Figure 2.. Methods and results of Experiment 2.
Top panel: Top-view schematic representation of the set-up and procedure used in the test of Experiment 2. Trials were composed by a pre-feeding phase (left panels) and a caching phase (right panels). The cacher bird received two trials with the transparent U-barrier (In-view condition, top panels), and two trials with the opaque U-barrier (Out-of-view condition, bottom panels). Within each condition, trials differed in the type of food (either peanuts, P, or macadamia nuts, M) that was provided to the observer in the pre-feeding phase. The cacher bird was always presented with a handful of maintenance diet (md) in the pre-feeding phase of all trials. Bottom panel: Box and whisker plots of data in Experiment 2. The plot on the left shows the difference in the number of peanuts cached minus the number of macadamia nuts cached for each condition, whereas the plot on the right shows the proportion of P cached (out of total items cached) in each condition. In the In-view condition, the observer had visual access to the caching tray, whereas in the Out-of-view condition, the observer did not have visual access to the caching tray. The colour of the boxes in the plot differs on the basis of the type of food that was provided to the observer in the pre-feeding phase: blue denotes that the observer had been pre-fed P and orange denotes that the observer had been pre-fed M.
Figure 3.
Figure 3.. Methods and results of Experiment 4.
Left: Top-view schematic representation of the set-up and procedure used in Experiment 4. In the familiarisation (left panels), the cacher bird received two trials, one in which the caching tray was placed near the opaque arm of the barrier (top panel), and one in which the tray was placed near the clear arm of the barrier (bottom panel). In the test (central and right panel), birds were tested in three conditions: Observed by dominant, Observed by subordinate, Private. In each condition, the cacher received two trials that differed in the orientation of the T-barrier. Right: Box and whisker plot of data in Experiments 3, 4, and in Legg and Clayton, 2014. The plot shows the average proportion of items cached in the out-of-view tray out of the total number of items cached, in the Private and Observed conditions. Note that data in the Observed by dominant and Observed by subordinate conditions were averaged for Experiment 4 and for Legg and Clayton, 2014’s study.
Figure 4.
Figure 4.. Methods and results of Experiments 5.
Left: Top-view schematic representation of the set-up and procedure used in the test of Experiment 5. Trials were composed by a pre-feeding phase (left panels) and a caching phase (right panels). The cacher bird received two trials with the transparent U-barrier (Barrier condition, top panels), and two trials with no barrier (No-barrier condition, bottom panels). Within each condition, trials differed in the type of food (either peanuts, P, or macadamia nuts, M) that was provided to the observer in the pre-feeding phase. The cacher bird was always presented with a handful of maintenance diet (md) in the pre-feeding phase of all trials. Right: Box and whisker plots of data in Experiment 5. The central plot shows the difference in the number of peanuts cached minus the number of macadamia nuts cached in the Barrier condition (left) and No-barrier condition (right). The plot on the right shows the proportion of P cached (over the total number of items cached) in the two conditions. The colour of the boxes in the plot differs on the basis of the type of food that was provided to the observer in the pre-feeding phase: blue denotes that the observer had been pre-fed P and orange denotes that the observer had been pre-fed M.
Figure 5.
Figure 5.. Box and whisker plot showing the mean number of items cached per trial in Experiments 1–5, Legg and Clayton, 2014 and Ostojić et al., 2017.
Note that Ostojić et al., 2017 tested California scrub-jays and Eurasian jays but only Eurasian jays were relevant to the analysis, and therefore included in the plot. MedianExperiment 1 = 10; MedianExperiment 2 = 3.75; MedianExperiment 3 = 5; MedianExperiment 4 = 1.83; MedianExperiment 5 = 6.5; MedianLegg & Clayton (2014) = 2.5; Median Ostojić et al., 2017 = 6.
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References

    1. Apperly IA, Butterfill SA. Do humans have two systems to track beliefs and belief-like states. Psychological Review. 2009;116:953–970. doi: 10.1037/a0016923. - DOI - PubMed
    1. Baker CL, Jara-Ettinger J, Saxe R, Tenenbaum JB. Rational quantitative attribution of beliefs, desires and percepts in human mentalizing. Nature Human Behaviour. 2017;1:0064. doi: 10.1038/s41562-017-0064. - DOI
    1. Balleine BW, Dickinson A. The role of incentive learning in instrumental outcome revaluation by sensory-specific satiety. Animal Learning & Behavior. 1998;26:46–59. doi: 10.3758/BF03199161. - DOI
    1. Bartsch K, Wellman H. Young Children’s Attribution of Action to Beliefs and Desires. Child Development. 1989;60:946–964. doi: 10.2307/1131035. - DOI - PubMed
    1. Bennett M, Galpert L. Complex belief-desire reasoning in children. Social Development. 1992;1:201–210. doi: 10.1111/j.1467-9507.1992.tb00124.x. - DOI

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