Eurasian jays (Garrulus glandarius) overcome their current desires to anticipate two distinct future needs and plan for them appropriatelyIntroductionMaterial and methodsSubjectsExperimental procedureSpecific satietyPlanning experimentAnalysisResultsSpecific satietyPlanningDiscussionWork adhered to home office licence PPL 80/1975.Research was funded by a BBSRC Grant, the Royal Society and the University of Cambridge. L.G.C. was funded by an MRC studentship. We thank Sergio Correia for all his help, as well as Charmaine Donovan and Ivan Vakrilov for care of the birds.head14Animal behaviourEurasian jays (Garrulusglandarius) overcometheir current desires toanticipate two distinctfuture needs and planfor them appropriatelyLucy G. Cheke and Nicola S. Clayton*Department of Experimental Psychology, University of Cambridge,Cambridge CB2 3EB, UK*Author for correspondence ([email protected]).Western scrub-jays (Aphelocoma californica)havebeen shown to overcome present satiety to cachefood they will desire in the future. Here, we showthat another corvid, the Eurasian jay (Garrulusglandarius), can distinguish between two distinctfuture desires and plan for each appropria-tely, despite experiencing a conflicting currentmotivation. We argue that these data addressthe criticisms of previous work, and suggest away in which associative learning processes andfuture-oriented cognition may combine to allowprospective behaviour.Keywords: mental time travel; Bischof-Ko¨hlerhypothesis; future planning; corvid1. INTRODUCTIONAnimals regularly act in the present to secure futurebenefits; however, much of this future-oriented behav-iour is driven by genetic predisposition [1] rather thanconscious awareness of the future. The ‘mental timetravel’ (MTT) hypothesis [2] states that the ability to‘re-experience’ the personal past (episodic memory)and ‘pre-experience’ the personal future (episodicfuture thinking) is uniquely human. The phenomenol-ogy of re- or pre-experiencing an event is usuallyassessed in humans using verbal description and maybe impossible to test for without language. The MTThypothesis thus risks being unfalsifiable. A furtherhypothesis, the Bischof-Ko¨hler hypothesis (BKH),states that animals’ apparently future-oriented actionsare driven only by current needs [2]. The advantage ofthe BKH is that it yields behavioural predictions fornon-verbal subjects: that animals cannot act for afuture need that is different from their current one.A number of studies have claimed to challenge theBKH [3–6]. Arguably, the best-controlled studyshowed that western scrub-jays cache food that theywould want when retrieving their caches, rather thanfood currently desired [7]. This study made use of aphenomenon known as ‘specific satiety’, in which anindividual sated on one food subsequently has reducedmotivation for that food relative to other foods. Thebirds were fed to satiety on one food before beinggiven the opportunity to cache that and another food.Later, birds were either fed the same food or a differentfood before cache-retrieval. By the third trial, those thatwere fed the same food in both phases (same group) con-tinued caching mostly the non-pre-fed food (the foodthey wanted at caching), but those that were fed a differ-ent food at retrieval (different group) cached a higherproportion of the pre-fed food (the food they wantedat cache-retrieval). One critique [8] argued that, as thedifferent group only showed a decrease in caching thenon-pre-fed food rather than an increase in the pre-fedfood, they were not responding to their future desires,just learning what not to cache. However, as satiationdoes not increase desire for a non-pre-fed food, butdecreases desire for a pre-fed food, one would notexpect an increase in pre-fed food. For example, if Ibuy a sandwich and a cake for tomorrow’s lunch, onlyto discover that sandwiches are provided, then this willnot mean that I will subsequently buy two cakes,merely that I will cease buying sandwiches.Here, we present an extension of the scrub-jay work[7] with a new species, the Eurasian jay (Garrulusglandarius), and a within-subjects design. Jays cachedin two locations, one which they could later retrievefrom after being pre-fed the same food as at caching,and one which they could later retrieve from afterbeing pre-fed a different food (figure 1a).2. MATERIAL AND METHODS(a) SubjectsFour Eurasian jays: Hoy and Ainsley (males), Hunter and Wiggins(females), all aged 2 years, pair-housed in 4  1  1 m cages whichcould be divided into two test areas by inserting opaque dividers.Birds were maintained at 21 + 18C on a 12 L : 12 D cycle. Birdsreceived a maintenance diet (MD) of kibble, vegetables, fruit andseeds. Water was always available. Subjects cached in Tupperwareboxes (17  24 cm) filled with wood chips and individuated bycoloured blocks.(b) Experimental procedureTwo experiments were conducted: ‘specific satiety’ and ‘planning’.(i) Specific satietyTo use the specific satiety procedure in the planning experiment, itwas necessary to first establish specific satiety in Eurasian jays. Sub-jects were food-deprived and isolated in half of their home cage for2 h before testing. They were then given 15 min access to a pow-dered/liquidized version of one of the test foods (food A: peanuts,food B: either suet pellets or raisins depending on birds’ preference).This processed food was not cacheable. Subjects were then given acaching tray, 40 items of food A and 40 items of food B and allowedto eat and cache for 15 min, the trays were then removed and thecages cleaned. Trays were inspected for caches out of sight. Thenumber of food items eaten was calculated as the items missingwhen the bowls, cage and trays had been searched. Trays werethen returned allowing cache-retrieval. Finally, birds were reunitedwith their cage-mate and MD was returned. This procedure wasthen repeated on a different day such that each bird was pre-fedboth foods once.(ii) Planning experimentEach bird received three trials of a three-stage procedure (figure 1a).Subjects were food-deprived and isolated for 1 h before each stage.On the first trial (‘baseline’), subjects were pre-fed MD before thecaching phase such that they would cache according to their generalpreference. On the two subsequent trials, they were pre-fed on oneof the test foods (powdered/liquidized), such that a preference forthe non-pre-fed food was established before the caching