question: Why is it that most domesticated mammals and birds seem to have "personalities" and "emotions", but fish and reptiles do not?
comment: Facial disparity. You are around mammals more than birds, reptiles, and fish. They also share more common musculature in and around the face. So they make expressions you are familiar with. Reptiles and birds we commonly encounter have their eyes farther to the side, and differently defined mouths. Ask longtime fish owners (people who have only 1-5 in a tank) and they will say their fish have personalities. Ask anyone who has had a bird more than a year and they will as well. I haven’t spoken much with any reptile owners about their pets, but would wager it is the same case there. Once familiar with the animal, you begin to attribute emotion to various actions.
passages: Personality in animals has been studied across a wide array of taxa. Some of these studies have investigated personality in mammals, elasmobranchs, reptiles, fish and birds, to name just a few. 
   Section::::Examples.:Crayfish.
   Section::::Evolutionary potential.
   The study of animal personality is largely based on the observation and investigation of behavioural traits. In an ecological context, traits or ‘characters’ are attributes of an organism that are shared by members of a species. Traits can be shared by all or only a portion of individuals in a population. For example, studies in animal personality often examine traits such as aggressiveness, avoidance of novelty, boldness, exploration and sociality.
  
  Section::::Background.
   Universal Nature of Expression: Darwin notes the universal nature of expressions in the book, writing: "the young and the old of widely different races, both with man and animals, express the same state of mind by the same movements."
   Section::::Concepts.:Social neuroscience.:Nonimmediate sociability.
  
  Two kinds of sociability exist: immediate and nonimmediate. The former depends upon sensory interaction with others such as smell, touch, sound or vision. Nonimmediate depends upon carrying the experience of the group within the head. Such sociability is already present in apes and is due to processes called mindmakers. But due to the modification of these mindmakers with symbolons, sociability in groups has become highly developed in humans. The combination of symbols and mindmakers created social mindware.
  
  Section::::Concepts.:Social neuroscience.:Mindmakers.
   Section::::Examples.:Birds.
  
  Marc Bekoff reported accounts of animal behaviour which he believed was evidence of animals being able to experience emotions in his book "The Emotional Lives of Animals". The following is an excerpt from his book:
   The motor centers of reptiles react to sensory cues of vision, sound, touch, chemical, gravity, and motion with pre-set body movements and programmed postures. With the arrival of night-active mammals, smell replaced vision as the dominant sense, and a different way of responding arose from the olfactory sense, which is proposed to have developed into mammalian emotion and emotional memory. The mammalian brain invested heavily in olfaction to succeed at night as reptiles slept – one explanation for why olfactory lobes in mammalian brains are proportionally larger than in the reptiles. These odor pathways gradually formed the neural blueprint for what was later to become our limbic brain.
   Some people oppose the concept of animal emotions and suggest that emotions are not universal, including in humans. If emotions are not universal, this indicates that there is not a phylogenetic relationship between human and non-human emotion. The relationship drawn by proponents of animal emotion, then, would be merely a suggestion of mechanistic features that promote adaptivity, but lack the complexity of human emotional constructs. Thus, a social life-style may play a role in the process of basic emotions developing into more complex emotions.
   Section::::Background.:Scientific approach.:Spindle neurons.
  
  Spindle neurons are specialised cells found in three very restricted regions of the human brain – the anterior cingulate cortex, the frontoinsular cortex and the dorsolateral prefrontal cortex. The first two of these areas regulate emotional functions such as empathy, speech, intuition, rapid "gut reactions" and social organization in humans. Spindle neurons are also found in the brains of humpback whales, fin whales, killer whales, sperm whales, bottlenose dolphin, Risso's dolphin, beluga whales, and the African and Asian elephants.
   Using this 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. 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."
  
  Cognitive biases have been shown in a wide range of species including rats, dogs, rhesus macaques, sheep, chicks, starlings and honeybees.
  
  Section::::Background.:Scientific approach.:Self-medication with psychoactive drugs.
   Moussaieff Masson and McCarthy describe a similar view (with which they disagree):
  
  Because of the philosophical questions of consciousness and mind that are involved, many scientists have stayed away from examining animal and human emotion, and have instead studied measurable brain functions through neuroscience.
  
  Section::::Background.:Comparative approach.
  
  In 1903, C. Lloyd Morgan published Morgan's Canon, a specialised form of Occam's razor used in ethology, in which he stated:
  
  Section::::Background.:Darwin's approach.
   The extent of personality phenomenon considered when examining animal personality is significantly reduced compared to those studied in humans. Concepts such as personal objects, identity, attitudes and life stories are not considered relevant in animals. Similarly, any approach that requires the subject to explain motives, beliefs or feelings is not applicable to the study of animal behaviour.
   Section::::Background.:Scientific approach.:Mechanistic.
  
  The second approach, mechanistic, requires an examination of the mechanisms that drive emotions and search for similarities in animals.
   Section::::Background.:Scientific approach.:Functional.
   Emotion in animals
  
  The existence and nature of emotions in 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 (and sometimes anecdotal) 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.
   Other researchers also believe that animal consciousness does not require a neocortex, but can arise from homologous subcortical brain networks. It has been suggested that brainstem circuits can generate pain. This includes research with anencephalic children who, despite missing large portions of their cortex, express emotions. There is also evidence from activation studies showing brainstem mediated feelings in normal humans and foetal withdrawal responses to noxious stimulation but prior to development of the cortex.
   Humans can suffer from a range of emotional or mood disorders such as depression, anxiety, fear and panic. To treat these disorders, scientists have developed a range of psychoactive drugs such as anxiolytics. Many of these drugs are developed and tested by using a range of laboratory species. It is inconsistent to argue that these drugs are effective in treating human emotions whilst denying the experience of these emotions in the laboratory animals on which they have been developed and tested.
   Several studies have also shown rodents can respond to a conditioned stimulus that has been associated with the distress of a conspecific, as if it were paired with the direct experience of an unconditioned stimulus. These studies suggest that rodents are capable of shared affect, a concept critical to empathy.
  
  Section::::Examples.:Horses.
   Neuroticism, agreeableness and extraversion are the most commonly found personality traits among measured animals. For example, chimpanzees show emotional stability, agreeableness and surgency, audiovisual reactivity, affect-extraversion, excitability-agitation, aggression affinity and social play.
  
  Section::::Correlated traits and behaviours.
  
  Some behaviours are correlated into a set of personality traits that remain constant throughout different situations and contexts. These traits are referred to as behavioural syndromes. For example, the aggressiveness-boldness syndrome refers to the correlation between an individuals aggressiveness with conspecifics and boldness in novel environments.
   Eugene Linden, author of "The Parrot's Lament" suggests there are many examples of animal behavior and intelligence that surpass what people would suppose to be the boundary of animal consciousness. Linden contends that in many of these documented examples, a variety of animal species exhibit behavior that can only be attributed to emotion, and to a level of consciousness that we would normally ascribe only to our own species.
  
  Philosopher Daniel Dennett counters that:
   It has been proposed that negative, withdrawal-associated emotions are processed predominantly by the right hemisphere, whereas the left hemisphere is largely responsible for processing positive, approach-related emotions. This has been called the "laterality-valence hypothesis".
  
  Section::::Etymology, definitions, and differentiation.:Basic and complex human emotions.
  
  In humans, a distinction is sometimes made between "basic" and "complex" emotions. Six emotions have been classified as basic: anger, disgust, fear, happiness, sadness and surprise. Complex emotions would include contempt, jealousy and sympathy. However, this distinction is difficult to maintain, and animals are often said to express even the complex emotions.
  
  Section::::Background.
  
  Section::::Background.:Behaviourist approach.
   Some researchers are beginning to investigate the question of whether dogs have emotions with the help of magnetic resonance imaging.
  
  Section::::Examples.:Cats.
   Emotions have been described as discrete and consistent responses to internal or external events which have a particular significance for the organism. Emotions are brief in duration and consist of a coordinated set of responses, which may include physiological, behavioural, and neural mechanisms. Emotions have also been described as the result of evolution because they provided good solutions to ancient and recurring problems that faced ancestors.
  
  Section::::Etymology, definitions, and differentiation.:Laterality.
   To test this in animals, an individual is trained to anticipate that stimulus A, e.g. a 20 Hz tone, precedes a positive event, e.g. highly desired food is delivered when a lever is pressed by the animal. The same individual is trained to anticipate that stimulus B, e.g. a 10 Hz tone, precedes a negative event, e.g. bland food is delivered when the animal presses a lever. The animal is then tested by being played an intermediate stimulus C, e.g. a 15 Hz tone, and observing whether the animal presses the lever associated with the positive or negative reward, thereby indicating whether the animal is in a positive or negative mood. This might be influenced by, for example, the type of housing the animal is kept in.
  
presuppositions: Fish and reptiles don't have personalities or emotions.
corrections: Fish and reptiles actually do have personalities, however due to humans being around the two less often than other pets it isn't noticed as much, the distance between their eyes also plays a big role.
raw_presuppositions: Fish and reptiles don't have personalities or emotions. Fish and reptiles don't have personalities or emotions.
raw_corrections: Fish and reptiles actually do have personalities, however due to humans being around the two less often than other pets it isn't noticed as much, the distance between their eyes also plays a big role. Fish and reptiles don't seem to have personalities or emotions because of facial disparities, but in fact still have them.