Measuring Cognitive Judgement Bias in Rats Using the Ambiguous‐Cue Interpretation Test

Justyna Papciak1, Rafal Rygula2

1 Currently at School of Physiology, Pharmacology and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, 2 Institute of Pharmacology, Polish Academy of Sciences, Department of Behavioral Neuroscience and Drug Development, Affective Cognitive Neuroscience Lab, Krakow
Publication Name:  Current Protocols in Neuroscience
Unit Number:  Unit 9.57
DOI:  10.1002/cpns.19
Online Posting Date:  January, 2017
GO TO THE FULL TEXT: PDF or HTML at Wiley Online Library


An active‐choice, operant, ambiguous‐cue interpretation (ACI) paradigm is described that can be used for measuring cognitive judgement bias in rats. In this behavioral test, animals in an operant conditioning chamber are trained to press a lever to receive a food reward when a specific tone is presented, and to press another lever in response to a different tone to avoid punishment by an electric foot‐shock. The tones, which serve as discriminative stimuli, acquire a positive or negative valence, and the training continues until the rats demonstrate a stable, correct discrimination between these two stimuli. The animals are tested after they have attained stable discrimination performance. The ambiguous‐cue test consists of a discrimination task, as described above, but includes the presentation of additional tones with frequencies that are intermediate between the trained positive and negative tones. The lever‐press response pattern to these ambiguous cues is considered an indicator of the rat's expectation of a positive or negative event; in other words, it is a measure of ‘optimism’ or ‘pessimism’, respectively. © 2017 by John Wiley & Sons, Inc.

Keywords: rat; ambiguous‐cue interpretation; pessimism; optimism; cognitive judgement bias

PDF or HTML at Wiley Online Library

Table of Contents

  • Reagents And Solutions
  • Commentary
  • Literature Cited
  • Figures
  • Tables
PDF or HTML at Wiley Online Library


Basic Protocol 1:

  • Rats: in our laboratory, we routinely use male Sprague‐Dawley rats (Charles River Laboratories; RRID: RGD 734476) that weigh ∼175 to 200 g at the beginning of the experimentation; however, any commercially available or laboratory‐bred rats previously reported to successfully perform lever‐press operant tasks could potentially be used)
  • Standard laboratory rat chow (e.g., Labofeed, Kcynia, Poland)
  • Commercially available sugar [used to prepare a 5% to 20% solution as a reward; see recipe in Reagents and Solutions]
  • Nontoxic mild detergent for cleaning (e.g., 100% Ludwik, Gora Kalwaria, Poland).
  • Water bottles for drinking water (900 ml, from, e.g., Ehret GmbH).
  • Type IV macrolon cages (59 × 38 × 20 cm, from e.g., Ehret GmbH) with metal mesh lids and food hoppers, lined with sawdust bedding (e.g., MIDI LTE E‐002 Abedot, Animalab, Poznan, Poland)
  • Scale for weighing the rats (e.g., Sartorius extend, Goettingen, Germany).
  • Nontoxic, permanent marker pen for tail marking (e.g., Pentel N850)
  • Set of computer‐controlled operant conditioning chambers enclosed in sound‐attenuating cubicles [we use a set of operant conditioning boxes obtained from Med Associates (cat. no. ENV‐008CT) constructed with a white polypropylene base; Perspex polycarbonate roof, door and rear panel; and two other walls with six (three per wall) sturdy aluminum channels that are designed to securely hold modular components; these modular walls consist of three equally sized lanes of panels that can be replaced with components with various sizes as required (1/2, 1/3, 1/4 of the wall length)]
    • Dimensions:
    • Base: 53.3 cm × 34.9 cm × 1.3 cm
    • Interior: 30.5 cm × 24.1 cm × 21.0 cm
    • Exterior: 31.8 cm × 25.4 cm × 26.7 cm
    • Channels: 6 channels (3 per wall; 7.62 cm each)
    • The modular components include the following: a house light (ENV‐215M, 28 V DC, 100 mA bulb) mounted on a 1/8 size modular panel (dimensions: 7.6 cm × 4.1 cm) with a partially open hood that should be rotated in the test chamber to reflect light off of the ceiling; a speaker (ENV‐224AM) mounted on a 1/4 size modular panel (dimensions: 7.6 cm × 8.3 cm) used with a programmable audio generator (ANL‐926) installed into the interface cabinet for each test chamber in the system (dimensions: 2.2 cm × 13.3 cm × 18.4 cm) able to generate pure tones at frequencies of 10 to 35000 Hz in 1‐Hz increments and amplitudes of 20 to 100 dB in 0.5 dB increments; a liquid dipper with a dual pellet/dipper receptacle (ENV‐202RM) mounted on a 1/2 size rat modular panel (dimensions: 7.6 cm × 16.5 cm, access opening: 5.1 cm × 5.1 cm) with a motor‐driven dipper arm that raises a precise 0.01‐cc stainless steel cup to deliver liquids that range from water to highly viscous fluids (such as a sucrose solution or condensed milk); 2 retractable stainless steel response levers (ENV‐112CM, dimensions: 4.8 cm × 1.9 cm) supplied on a 1/4 size rat modular panels (dimensions: 7.6 cm × 8.3 cm), with a 1.9‐cm lever protrusion and an adjustable tension from 15 to 100 g; and metal panels used to fill the remaining gaps in the walls. The location of all modules is shown in Figure . Each box is equipped with a stainless steel grid floor (ENV‐412, 2.2 cm × 13.3 cm × 18.4 cm) connected to a programmable shocker (ENV‐413, Computer Controlled Constant Current Aversive Stimulation Module) that can deliver scrambled electric shocks (0 to 10 mA) and a removable waste pan positioned underneath. The operant chambers are enclosed inside fan‐ventilated, sound‐attenuated cubicles (ENV‐018MD) that are manufactured using Multi Density Fiberboard (MDF), a high‐density wood composite with thermally infused high‐pressure laminate inside and out. The viewing port in the box's door allows for the researcher to observe the animal inside the cubicle without opening the door.
    • Dimensions:
    • Interior: 92.7 cm × 55.9 cm × 35.6 cm
    • Exterior: 100.3 cm × 59.7 cm × 39.4 cm
    • Walls: 1.9 cm thick
    • Controlling hardware:
    • A large tabletop cabinet and power supply with 28 V (SG‐6510D, 230 V, 50 Hz) is used to interface the input (e.g., tones or reward delivery) and the output (e.g., animal lever responses) of the operant chambers to a personal computer. The cabinet dimensions are 48.3 cm × 38.1 cm × 15.3 cm, and the cabinet has seventeen single‐width panels, with one slot reserved for the decode card (DIG‐700G).
    • An additional cabinet (SG‐6010, Rack Mount Interface Chassis, 120 V, 60 Hz) is used to house the shockers (ENV‐413); this cabinet contains seventeen individual single‐width slots that are used with the interface components that do not require 28 V, such as the programmable shock source (ENV‐413), scramblers (ENV‐414), or audio generators (ANL‐926)
    • A PCI network control (DIG‐729PCI, PCI High‐Speed Serial Microcontroller) is used to control the aversive stimulation delivery modules
    • Cables:
    • DB‐15 control cable(s) that are 15 feet (SG‐219C‐15) and 12 feet (SG‐219D) and shock output cable(s) that are 10 feet (SG‐219C‐10) are required for the computer‐controlled constant current aversive stimulator(s) (ENV‐413)
    • Personal computer:
    • A PC compatible with operant control software (e.g., MEDState notation code) and a PCI‐interfaced connection package (DIG‐700P2‐R2) that connects the tabletop interface cabinet (SG‐6510DA) to the operating system are required; this package includes the following: a PCI Interface Card (DIG‐704PCI‐2), a Decode Card (DIG‐700G), an Interface Ribbon Cable (DIG‐700C), and a main power cable (SG‐210CP‐2)
  • Programming software: MEDState notation code (MedAssociates) to program the behavioral protocols, control chambers, data processing and acquisition
  • Glass beaker (600 ml) for the preparation of the sucrose solution
  • Appropriate personal protective equipment (e.g., face mask, laboratory coat, boots etc.)
  • Laboratory notebook (for manual recording of the experimental details)
  • Data handling software (e.g., Microsoft Excel, GraphPad Prism; RRID: SCR 002798)
  • Data analysis software (e.g., SPSS; RRID:SCR 002865)
PDF or HTML at Wiley Online Library



Literature Cited

Literature Cited
   American Psychiatric Association. 2013. Diagnostic and Statistical Manual of Mental Disorders. 5th ed.: DMS‐5, Washington, D.C.
   Anderson, M.H. , Munafo, M.R. , and Robinson, E.S. 2013. Investigating the psychopharmacology of cognitive affective bias in rats using an affective tone discrimination task. Psychopharmacology (Berl) 226:601‐613. doi: 10.1007/s00213‐012‐2932‐5.
   Bateson, M. and Matheson, S. 2007. Performance on a categorisation task suggests that removal of environmental enrichment induces 'pessimism' in captive European starlings (Sturnus vulgaris). Anim. Welf. 16:33‐36.
   Bateson, M. , Desire, S. , Gartside, S.E. , and Wright, G.A. 2011. Agitated honeybees exhibit pessimistic cognitive biases. Curr. Biol. 21:1070‐1073. doi: 10.1016/j.cub.2011.05.017.
   Bethell, E.J. and Koyama, N.F. 2015. Happy hamsters? Enrichment induces positive judgement bias for mildly (but not truly) ambiguous cues to reward and punishment in Mesocricetus auratus . R. Soc. Open. Sci. 2:140399. doi: 10.1098/rsos.140399.
   Bethell, E.J. , Holmes, A. , Maclarnon, A. , and Semple, S. 2012. Evidence that emotion mediates social attention in rhesus macaques. PLoS One 7:e44387. doi: 10.1371/journal.pone.0044387.
   Boleij, H. , van't Klooster, J. , Lavrijsen, M. , Kirchhoff, S. , Arndt, S.S. , and Ohl, F. 2012. A test to identify judgement bias in mice. Behav. Brain Res. 233:45‐54. doi: 10.1016/j.bbr.2012.04.039.
   Briefer, E.F. and McElligott, A.G. 2013. Rescued goats at a sanctuary display positive mood after former neglect. Appl. Anim. Behav. Sci. 146:45‐55. doi: 10.1016/j.applanim.2013.03.007.
   Brydges, N.M. , Hall, L. , Nicolson, R. , Holmes, M.C. , and Hall, J. 2012. The effects of juvenile stress on anxiety, cognitive bias and decision making in adulthood: A rat model. PLoS One 7:e48143. doi: 10.1371/journal.pone.0048143.
   Carver, C.S. and Scheier, M.F. 2014. Dispositional optimism. Trends Cogn. Sci. 18:293‐299. doi: 10.1016/j.tics.2014.02.003.
   Doyle, R.E. , Hinch, G.N. , Fisher, A.D. , Boissy, A. , Henshall, J.M. , and Lee, C. 2011a. Administration of serotonin inhibitor p‐Chlorophenylalanine induces pessimistic‐like judgement bias in sheep. Psychoneuroendocrinology 36:279‐288. doi: 10.1016/j.psyneuen.2010.07.018.
   Doyle, R.E. , Lee, C. , Deiss, V. , Fisher, A.D. , Hinch, G.N. , and Boissy, A. 2011b. Measuring judgement bias and emotional reactivity in sheep following long‐term exposure to unpredictable and aversive events. Physiol. Behav. 102:503‐510. doi: 10.1016/j.physbeh.2011.01.001.
   Enkel, T. , Gholizadeh, D. , von Bohlen Und Halbach, O. , Sanchis‐Segura, C. , Hurlemann, R. , Spanagel, R. , Gass, P. , and Vollmayr, B. 2010. Ambiguous‐cue interpretation is biased under stress‐ and depression‐like states in rats. Neuropsychopharmacology 35:1008‐1015. doi: 10.1038/npp.2009.204.
   Gordon, D.J. and Rogers, L.J. 2015. Cognitive bias, hand preference and welfare of common marmosets. Behav. Brain Res. 287:100‐108. doi: 10.1016/j.bbr.2015.03.037.
   Hales, C.A. , Stuart, S.A. , Anderson, M.H. , and Robinson, E.S. 2014. Modelling cognitive affective biases in major depressive disorder using rodents. Br. J. Pharmacol. 171:4524‐4538. doi: 10.1111/bph.12603.
   Harding, E.J. , Paul, E.S. , and Mendl, M. 2004. Animal behaviour: Cognitive bias and affective state. Nature 427:312. doi: 10.1038/427312a.
   Hymel, K.A. and Sufka, K.J. 2012. Pharmacological reversal of cognitive bias in the chick anxiety‐depression model. Neuropharmacology 62:161‐166. doi: 10.1016/j.neuropharm.2011.06.009.
   Karagiannis, C.I. , Burman, O.H. , and Mills, D.S. 2015. Dogs with separation‐related problems show a "less pessimistic" cognitive bias during treatment with fluoxetine (Reconcile) and a behaviour modification plan. BMC Vet. Res. 11:80. doi: 10.1186/s12917‐015‐0373‐1.
   Keen, H.A. , Nelson, O.L. , Robbins, C.T. , Evans, M. , Shepherdson, D.J. , and Newberry, R.C. 2014. Validation of a novel cognitive bias task based on difference in quantity of reinforcement for assessing environmental enrichment. Anim. Cogn. 17:529‐541. doi: 10.1007/s10071‐013‐0684‐1.
   Kluemper, D. , LM, L. , and DeGroot, T. 2009. State or trait: Effects of state optimism on job‐related outcomes. J. Organ. Behav. 30:209‐231. doi: 10.1002/job.591.
   Matheson, S.M. , Asher, L. , and Bateson, M. 2008. Larger, enriched cages are associated with 'optimistic' response biases in captive European starlings (Sturnus vulgaris). Appl. Anim. Behav. Sci. 109:374‐383. doi: 10.1016/j.applanim.2007.03.007.
   Mendl, M. , Brooks, J. , Basse, C. , Burman, O. , Paul, E. , Blackwell, E. , and Casey, R. 2010. Dogs showing separation‐related behaviour exhibit a 'pessimistic' cognitive bias. Curr. Biol. 20:R839‐840. doi: 10.1016/j.cub.2010.08.030.
   Muller, C.A. , Riemer, S. , Rosam, C.M. , Schosswender, J. , Range, F. , and Huber, L. 2012. Brief owner absence does not induce negative judgement bias in pet dogs. Anim. Cogn. 15:1031‐1035. doi: 10.1007/s10071‐012‐0526‐6.
   Murphy, E. , Kraak, L. , van den Broek, J. , Nordquist, R.E. , and van der Staay, F.J. 2015. Decision‐making under risk and ambiguity in low‐birth‐weight pigs. Anim. Cogn. 18:561‐572. doi: 10.1007/s10071‐014‐0825‐1.
   Neave, H.W. , Daros, R.R. , Costa, J.H. , von Keyserlingk, M.A. , and Weary, D.M. 2013. Pain and pessimism: Dairy calves exhibit negative judgement bias following hot‐iron disbudding. PLoS One 8:e80556. doi: 10.1371/journal.pone.0080556.
   Papciak, J. , Popik, P. , Fuchs, E. , and Rygula, R. 2013. Chronic psychosocial stress makes rats more 'pessimistic' in the ambiguous‐cue interpretation paradigm. Behav. Brain Res. 256:305‐310. doi: 10.1016/j.bbr.2013.08.036.
   Parker, R.M. , Paul, E.S. , Burman, O.H. , Browne, W.J. , and Mendl, M. 2014. Housing conditions affect rat responses to two types of ambiguity in a reward‐reward discrimination cognitive bias task. Behav. Brain Res. 274:73‐83. doi: 10.1016/j.bbr.2014.07.048.
   Pomerantz, O. , Terkel, J. , Suomi, S.J. , and Paukner, A. 2012. Stereotypic head twirls, but not pacing, are related to a 'pessimistic'‐like judgment bias among captive tufted capuchins (Cebus apella). Anim. Cogn. 15:689‐698. doi: 10.1007/s10071‐012‐0497‐7.
   Rafa, D. , Kregiel, J. , Popik, P. , and Rygula, R. 2016. Effects of optimism on gambling in the rat slot machine task. Behav. Brain Res. 300:97‐105. doi: 10.1016/j.bbr.2015.12.013.
   Richter, S.H. , Schick, A. , Hoyer, C. , Lankisch, K. , Gass, P. , and Vollmayr, B. 2012. A glass full of optimism: Enrichment effects on cognitive bias in a rat model of depression. Cogn. Affect Behav. Neurosci. 12:527‐542. doi: 10.3758/s13415‐012‐0101‐2.
   Roelofs, S. , Boleij, H. , Nordquist, R. , and van der Staay, F.J. 2016. Making decisions under ambiguity: Judgment bias tasks for assessing emotional state in animals. Front. Behav. Neurosci. 10:119. doi: 10.3389/fnbeh.2016.00119.
   Rygula, R. and Popik, P. 2016. Trait "pessimism" is associated with increased sensitivity to negative feedback in rats. Cogn. Affect. Behav. Neurosci. 16:516‐526. doi: 10.3758/s13415‐016‐0410‐y.
   Rygula, R. , Pluta, H. , and Popik, P. 2012. Laughing rats are optimistic. PLoS One 7:e51959. doi: 10.1371/journal.pone.0051959.
   Rygula, R. , Papciak, J. , and Popik, P. 2013. Trait pessimism predicts vulnerability to stress‐induced anhedonia in rats. Neuropsychopharmacology 38:2188‐2196. doi: 10.1038/npp.2013.116.
   Rygula, R. , Papciak, J. , and Popik, P. 2014a. The effects of acute pharmacological stimulation of the 5‐HT, NA and DA systems on the cognitive judgement bias of rats in the ambiguous‐cue interpretation paradigm. Eur. Neuropsychopharmacol. 24:1103‐1111. doi: 10.1016/j.euroneuro.2014.01.012.
   Rygula, R. , Szczech, E. , Papciak, J. , Nikiforuk, A. , and Popik, P. 2014b. The effects of cocaine and mazindol on the cognitive judgement bias of rats in the ambiguous‐cue interpretation paradigm. Behav. Brain Res. 270:206‐212. doi: 10.1016/j.bbr.2014.05.026.
   Rygula, R. , Golebiowska, J. , Kregiel, J. , Holuj, M. , and Popik, P. 2015a. Acute administration of lithium, but not valproate, modulates cognitive judgment bias in rats. Psychopharmacology (Berl) 232:2149‐2156. doi: 10.1007/s00213‐014‐3847‐0.
   Rygula, R. , Golebiowska, J. , Kregiel, J. , Kubik, J. , and Popik, P. 2015b. Effects of optimism on motivation in rats. Front. Behav. Neurosci. 9:32. doi: 10.3389/fnbeh.2015.00032.
   Rygula, R. , Szczech, E. , Kregiel, J. , Golebiowska, J. , Kubik, J. , and Popik, P. 2015c. Cognitive judgment bias in the psychostimulant‐induced model of mania in rats. Psychopharmacology (Berl) 232:651‐660. doi: 10.1007/s00213‐014‐3707‐y.
   Salmeto, A.L. , Hymel, K.A. , Carpenter, E.C. , Brilot, B.O. , Bateson, M. , and Sufka, K.J. 2011. Cognitive bias in the chick anxiety‐depression model. Brain Res. 1373:124‐130. doi: 10.1016/j.brainres.2010.12.007.
   Verbeek, E. , Ferguson, D. , and Lee, C. 2014. Are hungry sheep more pessimistic? The effects of food restriction on cognitive bias and the involvement of ghrelin in its regulation. Physiol. Behav. 123:67‐75. doi: 10.1016/j.physbeh.2013.09.017.
PDF or HTML at Wiley Online Library