How Do Animals Feel: The Psychology and Physiology Behind Emotion

There are many who believe that animals have emotion and likewise many others that believe that they don’t. We are not talking about the fact that animals can feel sensations such as pain, the argument is do animals interpret their experience to assign a feeling to it (anger, sad, happy etc.).

What is Emotion?

Emotion is the state of a feeling characterized by expressive behaviors, physiological arousal, and cognitive interpretation of the experience. Emotion likely arose based on naming subdivided behaviors linked to primordial needs such as the need to eat, reproduce, expel waste, avoid injury, process environmental information, socialize, and deal with other species and threats. From there behaviors were subdivided into categories, such as shelter seeking behaviors, fight-or-flight behaviors, reproduction behaviors, foraging and eating behaviors, care-giving behaviors, elimination behaviors, investigative behavior, socialization behaviors, dominance/protection behaviors and even imitation behaviors that lead to emotional states.

An emotional state is simply the outcome of a readiness for action, cognition, and sensation. While other parts of the brain play roles in perceiving ‘emotion’, the basic physiological pathway is as follows: emotions originate in the thymus and relays messages from sensory organs. The autonomic nervous system is activated and skeletal muscles control the associated actions to the behavior. The cerebral cortex then interprets the experience and assigns it a description, which is what we refer to as an emotion.

There are a few psychological theories surrounding emotion that dictate emotion may not be the common sense human attribute that we think it is. The James-Lange Theory states that the activation of the autonomic nervous system and skeletal-muscular action occurs first and then the cognitive response interprets the experience and assigns it an emotion. The James-Lange Theory predicts two things: The first of which is that animals with a weak autonomic or skeletal muscular response should feel less ‘emotion’ and the second is that causing or increasing an autonomic or skeletal-muscular response should enhance ‘emotion’. The caveat here is that because humans and other primates have a higher cognitive ability, the cognitive aspect of an experience can occur because a situation calls for that emotion, but the individual may not feel much emotion. This provides evidence that feelings or emotions can be learned and therefor become a learned behavior.

Studies suggest that perceptions of the body’s actions contribute to emotional feelings, but feedback from the body is not sufficient to elicit or identify another emotion for example the body can respond to fear and anger in a similar physiological way.

The second theory is the Cannon-Bard Theory, which states that the body and mind are independently activated during a perceived event. With this being said, it does not deny that emotions are simply interpretations assigned to a perceived event. It is basically stating that the physical response and cognitive response occurs independently and the intensity of a reaction on one does not rely on the other.

The third theory is less supported. The Schachter’s Two-Factor Theory of Emotion states that emotion is based on physiological responses and cognitive interpretation of those responses. Here, people are physiologically stimulated can alter their cognitively intensify or diminish their own emotions. Not all research confirms this theory. One of the biggest arguments is cognitive intensification or diminishing of emotion is largely based on previous experiences that can shape the intensity of the emotion. This is conditioning, not emotionally based.

Emotional Theory Example


Let’s put these in perspective with the following scenario: You’re at work and you just found out that a significant other has cheated on you. You want to confront them, so you race to your car and drive to their location. On the way, you drive 15mph over the speed limit and a cop pulls you over. You get a speeding ticket. Let’s take a look at how these theories work:





The Physiology of Emotion and the Fight or Flight Response

Research has shown that emotions activate different regions of the brain, but they do not activate the same areas in different ways. While there are specific regions of the brain that receive more signal, that signal is not dependent on the type of emotion. The limbic system receives most of the neurological signal during an emotional state. The amygdala is crucial for emotional response. The frontal and temporal cortices are also activated during emotional situations. Additionally, scattered activation of other parts for the brain occurs, but it is ubiquitous and there is no activation pattern.
The Amygdala is the central to the fight or flight response. Depending on the experience an animal will either display attack behaviors or escape behaviors. Attack behaviors can be calm or passionate. Pain, other unpleasant experiences, and threats from other animals can trigger an attack behavior as well as an escape behavior. Each response is situational. During a fight response an animal behavior can bypass experience and prim an attack by stimulating the amygdala in emergency situations. This can even bypass genetic contributions, as genes often play a role in the probability of winning a fight. To put this example into practice think about how a small dog can seam overly aggressive to a big dog in an emergency situation such as unavoidable space encroachment. The little dog’s genes would dictate that it display an escape behavior, yet it stands its ground and tries to over compensate for its size by displaying hyper-aggressive behaviors (aka little dog; big bark).

Animals are only born with one innate fear known as the startle reflex. The startle reflex is when newborns are frightened by loud noises. Reflexes by definition are an innate behavior that every animal is born with and do not have to be learned. All other fear is learned through experience or taught to the offspring by a parent. Conditional fears are established by environmental situations interpreted by a series of input from auditory, visual, and sensory cues that are relayed via the corresponding neurons to specialized cells in the basolateral nucleus and central nucleus of the amygdala. Here the amygdala processes the information and sends output to the frontal cortex, which controls approach and avoidance responses. Additionally, axons lead to the middle of the brain relaying information to the pons, which controls the startle reflex. The amygdala also sends signals via axons to the hypothalamus, which is the control center for autonomic fear response and can also activate the sympathetic nervous system in times of brief stress to release epinephrine and norepinephrine from the adrenal medulla for a quick activation of the fight-or-flight response. During quick stress periods, the sympathetic nervous system also activates glands and smooth muscle.

Fight or Flight Physiology

The Hypothalamus also activates the Hypothalamic-Pituitary-Adrenal Axis (HPA Axis). The HPA Axis prepares the body for a fight or flight response. The activation signals a cascade of hormones to be released. When the Adrenal-Cortical system is activated, the adrenal glands release a hormone called corticotrophin releasing factor (CRF) that activates the pituitary gland. The pituitary gland then releases Adrenocorticotropic hormone (ACTH) to signal the adrenal cortex to release about 30 different hormones into the bloodstream that signal a fight-or-flight response. Cortisol and corticostrone are two of the thirty hormones released. They enhance metabolic activity and elevate blood sugar to provide added energy during the fight-or-flight response. Cortisol is also important in maintaining alertness during a response helps to fight infection and helps to heal wounds. Cortisol can be measured as an indicator of stress. In addition, temporary cortisol release enhances the immune system, while prolonged exposure impairs the immune system because it reduces the inflammatory pathways needed for fighting infection and wound healing. After a fight-or-flight response ends or after an ‘emotional’ event, the parasympathetic nervous system restores the body to homeostasis.

Do Animals Experience Emotions?

Notice that scientist do not question if most animals can feel sensations or even have anxiety or depression, but are animals able to use cognitive reasoning to determine what feeling is appropriate for an experience? Many people have an opinion about this topic, but how do you define what we know as sad? There are commonalities with animal behavior and human behavior and sometimes we are quick to assign a human emotion that describes a behavior because it is just what we know. How do you know that animals know what sad is as humans perceive it? The short answer is that it is impossible to know how an animal’s brain interprets an experience and if they have the higher cognitive ability to put a label on it such as angry. An ‘angry’ out burst may originate as a behavioral display because they are starving or because they want to show dominance. Not that they are necessarily angry. It is easy for us to relate an animal behavior to a behavior in common with humans. However, we go a step further and assign an emotion to it, which in itself is a learned behavior. This is a perfect example of anthropomorphism – assigning a human trait to a non-human behavior or appearance. It is clear that animals have feelings. They experience stress, anxiety, depression, and grief. They vocalize, mate, form bonds, have social structure, and guard resources. If you really think about it, being able to experience these feelings is a prerequisite for building and navigating relationships and interactions between species. While there are many opinions about if animals have emotions, as we know them, what does the science behind animal behavior tell us?

One thing is clear among scientists, you should not interpret an animal’s emotions without first knowing the individuals normal behaviors over a period of time. Behavior alone only provides a partial picture of any emotion. Emotions also require higher cognitive ability to give meaning and draw correlations between the behavior and an emotion. Not all animals have the capacity for this type of thinking. Defining emotion is a messy process because it is difficult to eliminate anthropomorphic perceptions (it is easy to explain things in relation to what you have experienced or know) and measure them scientifically. Some of the confusion could lie within the language we use to describe what is actually a natural behavior. Here are a few examples: we love and form friendships, and animals form bonds; we speak and animals vocalize; we feel jealous and animals guard their resources.

There is no true way to know if animals have emotion or not, but it is likely possible that they do not experience emotion the same way humans do. This is a difficult concept for humans to understand because we feel the need to compare animal behaviors to human behaviors and give them anthropomorphized emotional definitions. Some groups use this tactic to confuse the general public and sway them to believe in their agendas. They use tactics to get people to relate, when in fact, they may be mis-interpreting the behavior and the animal may not be feeling the emotion that humans perceive. It is clear that animals can feel, have sensations, and likely have their own emotions, but we don’t know how the animal defines emotion or what connection their emotion has to their experiences. Therefore, defining behaviors with human emotions and characteristics is not scientific.

If we can’t assign a human emotion to correlate to a behavior then how do we know what the animal feels? The short answer to that is by using behavioral studies and hormonal analyses to link the data to the behavioral data. That relationship can help researchers define if an animal is stressed. This is a better use of our time than assigning emotion. Activists often use this tactic when arguing against captivity. If an animal does not show an abnormal behavior and cortisol levels and other stress related hormones are normal, then the animal is not under stress. This is where science can help. Whether you believe the data or not is for you to decide. Just be aware of the facts and that our emotions that we have defined, are unique to us as humans and the definitions of such behavior is a learned behavior. It is likely that emotions are species specific and we should not use anthropomorphic terms and characterizations to define them.


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