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".
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]
Domestic pigs do not appear to develop a cognitive bias when kept in different stocking densities. Farmed pigs trained to expect food inside a bowl in one location and not in another, and then tested to show their responses to ambiguous spatial locations. Forty growing pigs were housed in groups of 10 at different density for 8 weeks prior to the start of the test. Tests on three occasions for each pig did not reveal any difference in cognitive bias according to the pig's history of stocking density. [10]
One study shows that restriction of collared peccaries (Pecari tajacu) in metabolism pens affects their emotional state and increases faecal glucocorticoid (a stress hormone) metabolite concentrations. The researchers noted that these effects were mitigated by environmental enrichment. [11]
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]
Fear is an intensely unpleasant primal emotion in response to perceiving or recognizing a danger or threat. Fear causes psychological changes that may produce behavioral reactions such as mounting an aggressive response or fleeing the threat. Fear in human beings may occur in response to a certain stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to oneself. The fear response arises from the perception of danger leading to confrontation with or escape from/avoiding the threat, which in extreme cases of fear can be a freeze response. The fear response is also implicated in a number of mental disorders, particularly anxiety disorders.
Operant conditioning, also called instrumental conditioning, is a learning process where voluntary behaviors are modified by association with the addition of reward or aversive stimuli. The frequency or duration of the behavior may increase through reinforcement or decrease through punishment or extinction.
Classical conditioning is a behavioral procedure in which a biologically potent stimulus is paired with a neutral stimulus. The term classical conditioning refers to the process of an automatic, conditioned response that is paired with a specific stimulus.
Animal cognition encompasses the mental capacities of non-human animals including insect cognition. The study of animal conditioning and learning used in this field was developed from comparative psychology. It has also been strongly influenced by research in ethology, behavioral ecology, and evolutionary psychology; the alternative name cognitive ethology is sometimes used. Many behaviors associated with the term animal intelligence are also subsumed within animal cognition.
Dog intelligence or dog cognition is the process in dogs of acquiring information and conceptual skills, and storing them in memory, retrieving, combining and comparing them, and using them in new situations.
Emotion is defined as any mental experience with high intensity and high hedonic content. The existence and nature of emotions in non-human animals are believed to be correlated with those of humans and to have evolved from the same mechanisms. Charles Darwin was one of the first scientists to write about the subject, and his observational approach has since developed into a more robust, hypothesis-driven, scientific approach. Cognitive bias tests and learned helplessness models have shown feelings of optimism and pessimism in a wide range of species, including rats, dogs, cats, rhesus macaques, sheep, chicks, starlings, pigs, and honeybees. Jaak Panksepp played a large role in the study of animal emotion, basing his research on the neurological aspect. Mentioning seven core emotional feelings reflected through a variety of neuro-dynamic limbic emotional action systems, including seeking, fear, rage, lust, care, panic and play. Through brain stimulation and pharmacological challenges, such emotional responses can be effectively monitored.
Behavioral enrichment is an animal husbandry principle that seeks to enhance the quality of captive animal care by identifying and providing the environmental stimuli necessary for optimal psychological and physiological well-being. Enrichment can either be active or passive, depending on whether it requires direct contact between the animal and the enrichment. A variety of enrichment techniques are used to create desired outcomes similar to an animal's individual and species' history. Each of the techniques used is intended to stimulate the animal's senses similarly to how they would be activated in the wild. Provided enrichment may be seen in the form of auditory, olfactory, habitat factors, food, research projects, training, and objects.
Comparative cognition is the comparative study of the mechanisms and origins of cognition in various species, and is sometimes seen as more general than, or similar to, comparative psychology. From a biological point of view, work is being done on the brains of fruit flies that should yield techniques precise enough to allow an understanding of the workings of the human brain on a scale appreciative of individual groups of neurons rather than the more regional scale previously used. Similarly, gene activity in the human brain is better understood through examination of the brains of mice by the Seattle-based Allen Institute for Brain Science, yielding the freely available Allen Brain Atlas. This type of study is related to comparative cognition, but better classified as one of comparative genomics. Increasing emphasis in psychology and ethology on the biological aspects of perception and behavior is bridging the gap between genomics and behavioral analysis.
Animal psychopathology is the study of mental or behavioral disorders in non-human animals.
Fish fulfill several criteria proposed as indicating that non-human animals experience pain. These fulfilled criteria include a suitable nervous system and sensory receptors, opioid receptors and reduced responses to noxious stimuli when given analgesics and local anaesthetics, physiological changes to noxious stimuli, displaying protective motor reactions, exhibiting avoidance learning and making trade-offs between noxious stimulus avoidance and other motivational requirements.
Separation anxiety in dogs describes a condition in which a dog exhibits distress and behavior problems when separated from its handler. Separation anxiety typically manifests within minutes of departure of the handler. It is not fully understood why some dogs suffer from separation anxiety and others do not. The diagnosis process often leads to a misdiagnosis as it is difficult to differentiate from other medical and behavioral problems. The behavior may be secondary to an underlying medical condition. With chronic stress, impairments to physiological health can manifest. Increased stress in the dog alters hormone levels, thus decreasing natural immunity to various health problems. Separation anxiety can be treated with systematic desensitization and, if necessary, medication. Ignoring or punishing the dog, leaving them to "cry it out" does not solve separation anxiety and can damage the mental health of dogs.
Cognitive bias modification (CBM) refers to procedures used in psychology that aim to directly change biases in cognitive processes, such as biased attention toward threat stimuli and biased interpretation of ambiguous stimuli as threatening. The procedures are designed to modify information processing via cognitive tasks that use basic learning principles and repeated practice to encourage a healthier thinking style in line with the training contingency.
The effects of stress on memory include interference with a person's capacity to encode memory and the ability to retrieve information. Stimuli, like stress, improved memory when it was related to learning the subject. During times of stress, the body reacts by secreting stress hormones into the bloodstream. Stress can cause acute and chronic changes in certain brain areas which can cause long-term damage. Over-secretion of stress hormones most frequently impairs long-term delayed recall memory, but can enhance short-term, immediate recall memory. This enhancement is particularly relative in emotional memory. In particular, the hippocampus, prefrontal cortex and the amygdala are affected. One class of stress hormone responsible for negatively affecting long-term, delayed recall memory is the glucocorticoids (GCs), the most notable of which is cortisol. Glucocorticoids facilitate and impair the actions of stress in the brain memory process. Cortisol is a known biomarker for stress. Under normal circumstances, the hippocampus regulates the production of cortisol through negative feedback because it has many receptors that are sensitive to these stress hormones. However, an excess of cortisol can impair the ability of the hippocampus to both encode and recall memories. These stress hormones are also hindering the hippocampus from receiving enough energy by diverting glucose levels to surrounding muscles.
Animal welfare science is the scientific study of the welfare of animals as pets, in zoos, laboratories, on farms and in the wild. Although animal welfare has been of great concern for many thousands of years in religion and culture, the investigation of animal welfare using rigorous scientific methods is a relatively recent development. The world's first Professor of Animal Welfare Science, Donald Broom, was appointed by Cambridge University (UK) in 1986.
Episodic-like memory is the memory system in animals that is comparable to human episodic memory. The term was first described by Clayton & Dickinson referring to an animal's ability to encode and retrieve information about 'what' occurred during an episode, 'where' the episode took place, and 'when' the episode happened. This ability in animals is considered 'episodic-like' because there is currently no way of knowing whether or not this form of remembering is accompanied by conscious recollection—a key component of Endel Tulving's original definition of episodic memory.
A preference test is an experiment in which animals are allowed free access to multiple environments which differ in one or more ways. Various aspects of the animal's behaviour can be measured with respect to the alternative environments, such as latency and frequency of entry, duration of time spent, range of activities observed, or relative consumption of a goal object in the environment. These measures can be recorded either by the experimenter or by motion detecting software. Strength of preference can be inferred by the magnitude of the difference in the response, but see "Advantages and disadvantages" below. Statistical testing is used to determine whether observed differences in such measures support the conclusion that preference or aversion has occurred. Prior to testing, the animals are usually given the opportunity to explore the environments to habituate and reduce the effects of novelty.
Theory of mind in animals is an extension to non-human animals of the philosophical and psychological concept of theory of mind (ToM), sometimes known as mentalisation or mind-reading. It involves an inquiry into whether non-human animals have the ability to attribute mental states to themselves and others, including recognition that others have mental states that are different from their own. To investigate this issue experimentally, researchers place non-human animals in situations where their resulting behavior can be interpreted as supporting ToM or not.
Pavlovian-instrumental transfer (PIT) is a psychological phenomenon that occurs when a conditioned stimulus that has been associated with rewarding or aversive stimuli via classical conditioning alters motivational salience and operant behavior. Two distinct forms of Pavlovian-instrumental transfer have been identified in humans and other animals – specific PIT and general PIT – with unique neural substrates mediating each type. In relation to rewarding stimuli, specific PIT occurs when a CS is associated with a specific rewarding stimulus through classical conditioning and subsequent exposure to the CS enhances an operant response that is directed toward the same reward with which it was paired. General PIT occurs when a CS is paired with one reward and it enhances an operant response that is directed toward a different rewarding stimulus.
Association in psychology refers to a mental connection between concepts, events, or mental states that usually stems from specific experiences. Associations are seen throughout several schools of thought in psychology including behaviorism, associationism, psychoanalysis, social psychology, and structuralism. The idea stems from Plato and Aristotle, especially with regard to the succession of memories, and it was carried on by philosophers such as John Locke, David Hume, David Hartley, and James Mill. It finds its place in modern psychology in such areas as memory, learning, and the study of neural pathways.
Pigs are among the most intelligent mammals on the planet, as such, they display a wide range of complex behaviors.