Cognitive bias in animals

Cognitive bias in animals is a pattern of deviation in judgment, whereby inferences about other animals and situations may be affected by irrelevant information or emotional states.^[1] It is sometimes said that animals create their own "subjective social reality" from their perception of the input.^[2] In humans, for example, an optimistic or pessimistic bias might affect one's answer to the question "Is the glass half empty or half full?"

To explore cognitive bias, one might train an animal to expect that a positive event follows one stimulus and that a negative event follows another stimulus. For example, on many trials, if the animal presses lever A after a 20 Hz tone it gets a highly desired food, but a press on lever B after a 10 Hz tone yields bland food. The animal is then offered both levers after an intermediate test stimulus, e.g. a 15 Hz tone. The hypothesis is that the animal's "mood" will bias the choice of levers after the test stimulus; if positive, it will tend to choose lever A, if negative it will tend to choose lever B. The hypothesis is tested by manipulating factors that might affect mood – for example, the type of housing the animal is kept in.^[3]

Cognitive biases have been shown in a wide range of species including rats, dogs, rhesus macaques, sheep, chicks, starlings and honeybees.^[4]^[5]

In what has been described as a "landmark study",^[6] the first study of cognitive bias in animals was conducted with rats. This showed that laboratory rats in unpredictable environments had a more pessimistic attitude than rats in predictable environments.^[3]

One study on rats investigated whether changes in light intensity – a short-term manipulation of emotional state – has an effect on cognitive bias. Light intensity was chosen as a treatment because this specifically relates to anxiety-induction. Rats were trained to discriminate between two different locations, in either high ('H') or low ('L') light levels. One location was rewarded with palatable food and the other with aversive food. Rats switched from high to low light levels (putatively the least negative emotional manipulation) ran faster to all three ambiguous locations than rats switched from low to high light levels (putatively the most negative manipulation).^[7]

Another study investigated whether chronic social defeat makes rats more pessimistic. To induce chronic psychosocial stress, rats were subjected to daily social defeat in a resident–intruder paradigm for three weeks. This chronic psychosocial stress makes rats more pessimistic.^[8]

Using the cognitive bias approach, it has been found that rats which are subjected to either handling or playful, experimenter-administered manual stimulation (tickling) showed different responses to the intermediate stimulus: rats exposed to tickling were more optimistic.^[4] The authors stated that they had demonstrated "...for the first time a link between the directly measured positive affective state and decision making under uncertainty in an animal model".

In pet dogs

Up to five million pet dogs in the UK, approximately 50% of the population, may perform undesirable separation-related behaviour when left home alone. Dogs were trained to move from a start position to a food bowl. When the bowl was on one side of the room ('positive' location, P) it contained a small quantity of food, and when on the opposite side ('negative' location, N) it was empty. In test trials, the bowl (empty) was placed at one of three ambiguous locations between P and N (near-positive (NP), middle (M), or near-negative (NN). Three test trials were presented at each location. The researchers measured how quickly the dogs moved to the ambiguous locations, fast indicating anticipation of food (an 'optimistic' judgement) or more slowly (a 'pessimistic' judgement).^{[clarification needed]} These cognitive bias tests show that dogs which exhibit high levels of separation-related behaviour in a separation test also have a more negative underlying mood.^[9]

In pigs

In honeybees

Honeybees become pessimistic after being shaken

Honeybees (Apis mellifera carnica) were trained to extend their proboscis to a two-component odour mixture (CS+) predicting a reward (e.g., 1.00 or 2.00 M sucrose) and to withhold their proboscis from another mixture (CS−) predicting either punishment or a less valuable reward (e.g., 0.01 M quinine solution or 0.3 M sucrose). Immediately after training, half of the honeybees were subjected to vigorous shaking for 60 s to simulate the state produced by a predatory attack on a concealed colony. This shaking reduced levels of octopamine, dopamine, and serotonin in the hemolymph of a separate group of honeybees at a time point corresponding to when the cognitive bias tests were performed. In honeybees, octopamine is the local neurotransmitter that functions during reward learning, whereas dopamine mediates the ability to learn to associate odours with quinine punishment. If flies are fed serotonin, they are more aggressive; flies depleted of serotonin still exhibit aggression, but they do so much less frequently.

Within 5 minutes of the shaking, all the trained bees began a sequence of unreinforced test trials with five odour stimuli presented in a random order for each bee: the CS+, the CS−, and three novel odours composed of ratios intermediate between the two learned mixtures. Shaken honeybees were more likely to withhold their mouthparts from the CS− and from the most similar novel odour. Therefore, agitated honeybees display an increased expectation of bad outcomes similar to a vertebrate-like emotional state. The researchers of the study stated that, "Although our results do not allow us to make any claims about the presence of negative subjective feelings in honeybees, they call into question how we identify emotions in any nonhuman animal. It is logically inconsistent to claim that the presence of pessimistic cognitive biases should be taken as confirmation that dogs or rats are anxious but to deny the same conclusion in the case of honeybees."^[12]

v t e Biases
Cognitive biases	Acquiescence Ambiguity Affinity Anchoring Attentional Attribution Actor–observer Fundamental Group Ultimate Authority Automation Double standard Availability Mean world Belief Blind spot Choice-supportive Commitment Confirmation Selective perception Compassion fade Congruence Cultural Declinism Distinction Dunning–Kruger Egocentric Curse of knowledge Emotional Extrinsic incentives Fading affect Framing Frequency Frog pond effect Halo effect Hindsight Horn effect Hostile attribution Impact Implicit In-group Intentionality Illusion of transparency Mean world syndrome Mere-exposure effect Narrative Negativity Normalcy Omission Optimism Out-group homogeneity Outcome Overton window Precision Present Pro-innovation Proximity Response Rosy retrospection Restraint Self-serving Social comparison Social influence bias Spotlight Status quo Substitution Time-saving Trait ascription Turkey illusion von Restorff effect Zero-risk In animals
Statistical biases	Estimator Forecast Healthy user Information Psychological Lead time Length time Non-response Observer Omitted-variable Participation Recall Sampling Selection Self-selection Social desirability Spectrum Survivorship Systematic error Systemic Verification Wet
Other biases	Academic Basking in reflected glory Déformation professionnelle Funding FUTON Inductive Infrastructure Inherent In education Liking gap Media False balance Vietnam War South Asia United States Arab–Israeli conflict Ukraine Net Political bias Publication System justification Reporting White hat Ideological bias on Wikipedia
Bias reduction	Cognitive bias mitigation Debiasing Heuristics in judgment and decision-making
Lists: General Memory

v t e Animal cognition
Cognition	Animal communication Animal consciousness Animal culture Animal language Great ape language Talking animal Talking bird Animal-made art Animal navigation Cognitive bias Cognitive ethology Comparative cognition Emotion Insect Mirror test Neuroethology Number sense Observational learning Primate archaeology Theory of mind Tool use sea otters Vocal learning
Intelligence	Bird Pigeon Cat Cephalopod Cetacean Dog Elephant Fish g factor in non-humans Primate Hominid Swarm
Pain	Pain in amphibians Pain in animals Pain in cephalopods Pain in crustaceans Pain in fish Pain in invertebrates
Relation to brain	Brain size Brain-to-body mass ratio Encephalization quotient Neuroscience and intelligence Number of neurons
Category

v t e Emotions (list)
Emotions	Acceptance Admiration Adoration Aesthetic Affection Agitation Agony Amusement Anger Angst Anguish Annoyance Anticipation Antipathy Anxiety Apathy Arousal Attraction Awe Belongingness Boredom Calmness Comfort Compassion Confidence Confusion Contempt Contentment Courage Cruelty Curiosity Defeat Depression Desire Disappointment Disgust Distrust Doubt Ecstasy Embarrassment vicarious Emotion work Empathy Emptiness Enthrallment Enthusiasm Envy Euphoria Excitement Faith Fear Flow Frustration Fun Gratification Gratitude Greed Grief Guilt Happiness Joie de vivre Hatred self-hatred Hiraeth Homesickness Hope Horror Hostility Humiliation Hygge Hysteria Ikigai (sense of purpose) Indulgence Infatuation Insecurity Insignificance Inspiration Interest Irritation Isolation Jealousy Joy Kindness Loneliness Love at first sight limerence obsessive parental passionate and companionate Lust Mono no aware Neglect Nostalgia Outrage Panic Passion Pity self-pity Pleasure Pride grandiosity hubris insult vanity Rage Regret Rejection Relaxation Relief Remorse Resentment Revenge Sadness melancholy Saudade Schadenfreude Sehnsucht Sentimentality Shame Shock Shyness Solitude Social connection Sorrow Spite Stress chronic Suffering Surprise Suspense Suspicion Sympathy Trust Wonder sense of wonder Worry Zest
Worldviews	Cynicism Defeatism Fatalism Misanthropy Nihilism Optimism Pessimism Reclusion Weltschmerz
Related	Affect consciousness in education measures in psychology Affective computing forecasting neuroscience science spectrum Affectivity positive negative Appeal to emotion Amygdala hijack Emotion and art and memory and music and sex and sleep classification circumplex EmojiGrid Lövheim PAD Plutchik evolution expressed functional accounts group homeostatic in animals perception recognition in conversation regulation interpersonal work Emotional aperture bias blackmail competence conflict contagion detachment dysregulation eating exhaustion expression and gender intelligence and bullying Empathy quotient intimacy isolation lability labor lateralization literacy prosody reasoning responsivity security symbiosis thought method well-being Emotionality bounded Emotions and culture history in decision-making in the workplace in virtual communication moral self-conscious social social sharing sociology Feeling Group affective tone Interactions between the emotional and executive brain systems Jealousy in art Mental state Meta-emotion Pathognomy Pathos Social emotional development Stoic passions Theory affect affect as information appraisal Cannon–Bard constructed emotion discrete emotion James–Lange somatic somatic marker two-factor
Italics indicate emotion names in foreign languages Category

v t e Ethology
Branches	Animal cognition Animal communication Animal consciousness Animal culture Animal sexual behaviour Animal welfare science Anthrozoology Bee learning and communication Behavioural ecology Behavioral endocrinology Behavioural genetics Breed Cognitive ethology Comfort behaviour Grooming Comparative psychology Emotion in animals Ethogram Evolutionary neuroscience Feeding Hover Human ethology Instinct Learning Neuroethology Pain in animals Philosophical ethology Sociobiology Species-typical behavior Stereotypy Structures Hive Honeycomb Nest Instinct Swarm Tool use by non-humans Zoosemiotics Zoomusicology
Ethologists	Patrick Bateson Marc Bekoff Donald Broom John B. Calhoun Charles Darwin Marian Dawkins Richard Dawkins Irenäus Eibl-Eibesfeldt Dian Fossey Karl von Frisch Jane Goodall Heini Hediger Julian Huxley Konrad Lorenz Desmond Morris Thomas Sebeok William Homan Thorpe Nikolaas Tinbergen Jakob von Uexküll Wolfgang Wickler E. O. Wilson Solly Zuckerman
Societies	Association for the Study of Animal Behaviour International Society for Applied Ethology
Journals	Animal Behaviour Animal Cognition Animal Welfare Behavioral Ecology Behaviour
Category

Cognitive bias in animals

In pet dogs

In pigs

In honeybees

References

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