People can do bizarre things. Things that we sometimes fail to find logical explanation for. Such travesties as a young man shooting up innocent people at his school or in the local mall, a pregnant woman smoking crack cocaine, or a man married for 35 years deciding to cheat on his wife. Both irrational and irrational behaviors can ultimately be explained once we understand what forces motivate people to act.
One person is happy laying on the beach all day, watching TV and eating junk food. Another prefers going out to run a marathon and then studying for the classes they’re in. Both found motivation for their behavior but obviously there is a distinct difference between the lifestyle preferences of each. Figuring out why these motivation differences exist has always interested people. Plato tried to figure out where reason comes from in his efforts to describe behavior. Descartes sought distinction between the mind and body, and Wilhelm Wundt, one of the first psychologists, wanted to figure out what causes human feeling to modify action and behavior.
Theories have been formulated to try and help us better understand why people are motivated, though there is not one that can fully explain all behavior perfectly. Humans are very complex and our actions are often motivated by a myriad of varying factors. Most modern psychologists agree, however, that motivation stems from a mix of inborn characteristics and external learning.
Motivation is defined as any condition, internal to an organism, that appears by inference to initiate, activate, or maintain goal-directed behavior.  The condition has four parts.
- Internal Condition – Motivation develops from internal conditions. These conditions can be based on physiological needs, such as wanting to reproduce or they can be based on more complex desires such as wanting to become a doctor to help people who are sick.
- Observed by inference – One’s motivation is assumed to be a cause of their behavior, making it inferred.
- Initiation, activation, or maintenance – Motivation can cause people to do something they never have before, go back to an old behavior, or modify their current behaviors.
- Goal-directed behavior – Motivation causes people to try and reach goals. For instance, a person in pain will feel motivated to get some painkillers to reach their goal– the elimination of pain.
There are four main categories of theory which try to explain motivation. Drive reduction theories, learned motives theories, cognitive theories, and humanistic theories.
Drive Reduction Theories
Drive reduction theories are based on the idea that people will seek out goals which will balance, reestablish, or maintain their survival.  We have physiological needs mostly in the form of hunger, thirst, and sexual motivation. These needs are mechanistic because they occur without our control. We get hungry when we have not eaten, thirsty when we have not drank, etc. A drive is an internal arousal which causes an organism to satisfy its physiological needs. Organisms will enter into a ‘drive state’ to satisfy their physiological imbalances. Physiological drives are based mostly on biological factors.
Hunger is definitely one of the most powerful drives that humans have. For thousands of years we have worked as a means to get food. People have been starved to get them to do things. Food is the key to life so we are always trying to satiate our appetites. Food is also comforting. It is used as a coping mechanism and acts on the chemistry of our bodies the same way that an addictive drug does. This is why the world is currently in an obesity epidemic that only seems to be getting worse as time goes on.
In this theory, hunger is said to come from chemical imbalances which occur from low blood sugar levels.  When a person does not eat anything their cells lack the glucose they need, which triggers chemicals to be released that tell the brain to eat. We get hunger pangs in the stomach, dizziness, headaches, etc. Once food has been digested and glucose has been sent to the cells of the body and brain, hunger will go away.
Scientists have studied areas of the brain on a quest to find the source of hunger. What research has shown is that hunger originates mostly from an area in the forebrain called the hypothalamus.  When a person’s stomach is empty their lateral hypothalamus is activated and the person gets a signal to search for food and eat. Once a person is full of food fat cells will release the hormone leptin which then stimulates the ventromedial nuclei, activating a signal to stop eating.  The paraventricular hypothalamus tells the body what foods it needs and is the cause of ‘cravings’.
Hormones are an important part of feeling hunger. The pancreas releases insulin into the bloodstream when a person has eaten something with sugar. After the sharp increase in blood-sugar levels, insulin is quickly released by the pancreas. The person feels relief from hunger but then might have an increase in hunger shortly afterward depending on the food they ate.  This happens especially when people eat very sugary foods like candy bars. Foods high in sugar and starch will quickly raise the level of insulin in the body, helping metabolization of the sugar. Once the glucose has been metabolized, the body will crash back into hunger as the pancreas stops secreting insulin and the hormone disappears from the blood stream.
Hunger Gone Haywire
Obesity is a disease characterized by someone who has a body mass index greater or equal to 30. A body mass index of 25 to 29.9 is characterized as being overweight.  Body mass index is weight divided by height squared. The world is currently experiencing an alarmingly high percentage of overweight and obese people. As of 2005, the percentage of obese men in the United States was 33.3%, while women were at 35.3%. Adolescents and children are also experiencing high levels of obesity at 16.3%.  Something is making people overeat and psychologists and doctors find obesity a pressing issue.
- Genetics - A person is born with a genetically determined number of fat cells.  It has been proposed that people born with more fat cells are more likely to overeat and become obese than those born with less fat cells. Depending on how a person eats while they are growing, the size of those fat cells will either grow or shrink. We can never lose fat cells. The body attempts to keep fat cells at a constant level and when a person has shrunk those cells through dieting the body enters into a state of deprivation, causing the person to overeat. When people overeat they can add new fat cells to their body. This leads to an endless cycle in which a person is unable to lose weight for any extended period of time and will ultimately gain weight– becoming overweight or obese.
Our bodies have a set point, or a weight that the body tries to maintain. This set point is determined by genetics, early nutrition, learned habits, and current environment.  We can inherit slow metabolisms and the desire to overeat. Thus, it is often times impossible for some people to lose weight because their bodies will fight against them, regulating metabolism and hormones to reach the set point and homeostasis. It is easier for these people to lose weight by expending energy through exercise than it is to try and restrict calories.
- Psychological Factors – People learn about food and how to eat through the people and environments around them. If someone grows up in a family that centers their lives around eating fatty and sugary foods, then that person is likely going to adhere to that lifestyle and become overweight or obese.  Parents will often reward their child’s good behavior with desserts or fatty snacks. Outside of the family there are just as many influential factors like advertisements, friends, coworkers, or other social atmospheres. Society often places a lot of importance on events that center around food. With people surrounded by others who are eating to reward themselves, socialize, or be happy– it only makes sense that they do the same.
People who have experienced emotional trauma and are angry or sad will often turn to food as a coping mechanism.  The same happens to those who are under a great deal of stress.
- External Cues – People are also influenced by external cues that will cause them to seek food. Studies have shown that people who are obese will eat more than normal-weight people when the food is easily available but less when the food is difficult to get.  Another study showed that obese people will eat more when the food is brightly illuminated. Sight and availability of food therefore motivate overweight people to eat more than normal-weight people, who eat because of internal (physiological) cues. Obese people are also more likely to be tempted by foods at a buffet or dinner parties and take abnormally large proportions, whereas normal-weight people take less proportions or are capable of stopping themselves once they’ve ate enough.
- Dieters – People who are used to dieting are usually overweight or obese. Studies show that these dieters are more likely to binge eat once they’ve consumed something that isn’t on their diet plan.  People who don’t diet will not binge after they find out that they’ve eaten something that is high in calories. Obese people are also more likely to break their diet plan when they are offered something that they know is unhealthy or high in calories. Non-dieters are able to say no and resist such foods more easily.
People who develop abnormal eating behaviors and reactions to food are said to have eating disorders. Some examples of eating disorders are Anorexia Nervosa, Bulimia Nervosa, and Compulsive Overeating.
- Anorexia Nervosa – Those that refuse to keep their body weight at a healthy level for their height, age, and body build or have an obsessive fear of gaining weight and a body image distortion have anorexia nervosa. They refuse food or avoid situations where food is present. Anorexics are therefore highly motivated to be as skinny as possible. They often can’t acknowledge that they have a problem and fail to have accurate images of themselves. Self-esteem issues usually accompany Anorexia too. The disease usually happens in young high school age girls who come from successful families, though it can develop in anyone– including men. Anorexia develops for a number of different reasons.  Some people are emotionally traumatized, stressed, or have a fear of growing up. Others are perfectionists that feel they must keep getting thinner to make their family, attractions, or coaches happy. Often times the media is blamed for instilling the belief in people that they must be thin to be beautiful. Some develop anorexia because it is the only way that they feel they can have any sense of control in their lives. It may be a combination of any of these factors or a completely different psychological reason. No matter what the cause is, Anorexia is one of the most deadly of all psychological disorders, killing at least 1000 people every year. 
- Bulimia Nervosa – Another common eating disorder is bulimia nervosa, which involves binge eating and a fear of not being able to stop eating. After binge eating, those with bulimia will often purge, or cause themselves to throw up. They might also rely on laxatives, diuretics or compulsive eating as methods of purging.  Those who grow up in households where dieting and weight issues are common will have a higher likelihood of developing bulimia than other people.
- Compulsive Overeating – Those who suffer from compulsive overeating will often binge and be overweight. They can suffer from depression, anti-social behavior, and self-esteem issues. 
An average adult human is composed of 60 to 70% water. It makes sense then that we are instinctually wired to drink liquids and keep ourselves quenched. Thirst is important because it keeps our bodies healthy and our moods happy. Two-thirds of the body’s fluid is in the cells, where it is regulated by the hypothalamus. Fluid outside of the cells is mostly regulated by the kidneys and pituitary gland.  When the body is lacking water, the pituitary and hypothalamus send signals for us to drink. These signals will not subside until the cells in our body have gotten the water they’re asking for. Thirst has almost nothing to do with dryness of the mouth and everything to do with dryness of the body. Those who do not keep themselves properly hydrated will die. We develop preferences for what liquids we want to quench our thirsts with, and it is possible to drink too much.
The desire to reproduce is one of the strongest physiological drives, on par with hunger and drinking. Satisfying the sex drive, however, can be a lot more complex than it is with hunger or thirst. People have evolved through time to link sex with the desire for romance and long term relationships. Modern society portrays sex in many different ways and it is up to the individual to decide how they want to respond to their sexual instincts. In this way, sex is a drive that is easier to control than the others since it isn’t necessary for the survival of our bodies. Everyone is wired to seek sex which is why society constantly uses it sell products or entertain. The sex drives of men usually respond to visual cues whereas women respond more to emotional cues. Both sexes are highly motivated to have sex, and it can have some very interesting effects on behavior. 
The sex drive is mostly controlled by hormones like testosterone and estrogen. When these sex hormones are released they elicit a sexual response. In many animals, sex is an uncontrollable act that will happen whenever hormones are released. Humans have an easier ability to control our response to hormones, though we can lose control as well. Sex hormones cause us to engage in acts other than just sexual intercourse. Some hormones are responsible for giving women their maternal instincts to care and raise children. Testosterone and estrogen give men and women aggressiveness, kindness, irritability, athleticism, and the ability to think clearly, as well as many other things.  The sex drive and it’s hormones play a huge role in motivating humans to accomplish tasks in hopes that it will improve their chances of reproducing.
Sexual Response Cycle
When sexually aroused, humans go through four stages known as sexual response cycle. 
- Excitement Phase – In this first stage, the peson’s heart rate, blood pressure, and respiration increase. They experience vasoconstriction which is the engorgement of blood vessels, especially in the genital area. This stage can last any length of time, depending on the stimulation the person is getting to make them excited. Such stimulation can be conversation, physical contact, fantasy, etc.
- Plateau Phase – During this stage men and women will be preparing for orgasm. The autonomic nervous system gains more control and the heart beats faster. In men, the penis will become enlarged. Women’s vaginas will become engorged, lubricated, and elongated. This stage will usually last several minutes to a couple of hours.
- Orgasm Phase - In this stage the autonomic nervous system activity reaches its peak. Muscle contractions occur all over the body and especially in the genital area where men will ejaculate semen and women’s vaginas will contract. Men experience one orgasm during a sexual session whereas women can experience multiple orgasms. Each orgasm lasts only seconds.
- Resolution Phase – Here, in the resolution phase, the body returns to its natural resting state. Both sexes will feel relaxed, peaceful, and usually tired. Men will not be able to orgasm for awhile since they must go through a rejuvination process called the refractory period. Women can sometimes be quickly stimulated and brought back to the orgasm phase with little rest.
Sexual dysfunction is a term used to describe someone who is has the inability to obtain satisfaction from sexual behavior. Sexual dysfunction can have roots in a person’s upbringing, where they may have been introduced to or learned about sex in such a way that they developed abnormal views about it. Other times sexual dysfunction can occur from too much drugs and alcohol.  Sexual dysfunctions are usually treated in therapy or psychoanalytic sessions by psychologists or other mental health workers.
When a man is not able to attain or maintain an erection in order to engage in sexual intercourse, they are said to be suffering from an erectile dysfunction. Erectile dysfunction can be caused by emotional problems, alcohol and drugs, damage to the central nervous system, and anatomical defects. There are two kinds of erectile dysfunction.
- Primary Erectile Dysfunction – A man who has never held an erection strong enough or long enough for sexual intercourse suffers from primary erectile dysfunction.  This may be caused by physical defects or a fear and anxiety about sex. Often times such dysfunctions can be based on what occurs in a young man’s life, where they might experience something which gives them an unusual sensitivity to the matter of sexual relations.
- Secondary Erectile Dysfunction - Those who have successfully had sex in the past but are now incapable of getting or keeping an erection have secondary erectile dysfunction. When a man fails to get an erection in 25% of his sexual attempts, then he has secondary erectile dysfunction. Those who suffer from this dysfunction will often keep vivid memories of failed sexual encounters that keep them from ever being able to get an erection.  Every time they try and get an erection they will have fear and anxiety based on the last time they failed to get an erection, and that fear and anxiety keeps them flaccid.
- Premature Ejaculation – If a man is unable to delay his ejaculation long enough to sexually satisfy his partner during at least half of his sexual encounters.  Premature ejaculation is usually caused by psychological and emotional factors. Usually the main will have either fear or anxiety about sexual intercourse because of bad sexually related memories. One treatment for premature ejaculation is to try and teach men not to fear failure. If the man is taught to relax and look at sex as something sensual and pleasurable, then the premature ejaculation problem should disappear over time.
- Primary Orgasmic Dysfunction – Women who can never achieve orgasm through sexual stimulation have primary orgasmic dysfunctions.  A lot of the causes of this dysfunction are physically related, but they are also often psychological. Women who are extremely religious or fail to communicate with their partners will often find that they cannot orgasm. Women who have unfavorable views of sex due to social stigmatization or childhood trauma will also be susceptible to the dysfunction.
- Secondary Orgasmic Dysfunction - If a woman has achieved orgasm in the past but is now unable to orgasm during sexual situations, then she has secondary orgasmic dysfunction.  This dysfunction often occurs when a woman finds her mate sexually unattractive or undesirable. Women can also feel like orgasms are something bad, and that they should be ashamed or guilty to be having them. These women could have experienced traumatic events while growing up which has caused her to have an unhealthy view of sex as an adult.
When a woman is treated for orgasmic dysfunctions, she will often go through therapy which tries to uncover the underlying psychological reasons for her inability to enjoy sex. By discussing her innermost views about sex, she and her partner should better understand what is wrong. After taking time away from sex, they should have intercourse in an unhurried fashion with respect and intimacy. As long as the atmosphere is relaxed and the man is able to successfully stimulate the woman both spiritually and physically, then orgasm should occur. 
Sensory Stimulation and Arousal Theory
People are motivated to seek sensory stimulation, such as the sounds of music, the action in a movie, or the feeling of swinging a baseball bat. Sensory stimulation involves the use of any or all of the five senses.  If humans are deprived of sensory stimulation they do not find themselves physiologically impaired, but rather they will become irritable or depressed. All animals enjoy sensory stimulation. Cats often like to wonder around and find new areas they’ve never been before, and monkeys will play with human made tools, puzzles, and toys. People are instinctively wired to explore their worlds and seek sensory stimulation from the objects and people around them. It is especially important for children to get sensory stimulation to help them form neural pathways.  We are motivated to use our senses and receive feedback by engaging in activities.
Arousal theory attempts to explain what the drive theories and sensory stimulation theory cannot. Arousal theory states that we perform best when we are aroused.  Arousal is the activation of the central nervous system, the muscles, and the glands. The theory has been extended by modern research to say that when a person’s arousal level and anxiety is too high or too low, their performance will be poor. If you can think back to a time when you were playing a sport, and were very happy to go to practice and play games, then chances are you did well at the sport. If you hated practice and did not care about the sport at all, you probably did bad. Furthermore, a state of over-arousal can lead to anxiety and failure to perform. An example would be having everyone in a stadium relying on you to make the winning play and win the championship. Some might respond by doing well while others would be crippled by the pressures of such a situation. Performance, therefore, is best when arousal is at a moderate level. 
The traditional take on arousal theory’s relation to motivation and behavior is that when excitement levels increase for any drive it will result in an increased effectiveness of behavior. For instance, someone who is very dehydrated will do anything they can, as fast as they can, to get liquid into their bodies. Their heightened drive causes an increase in motivation. Arousal theory can be used to explain irrational behavior, such as teenagers who speed in their cars or people who steal and commit crimes. They might find that such thrilling actions increase their state of arousal, which makes them good at the act and reinforces the chances that they will continually do it.
Connecting thought and motivation, expectancy theory states that a person’s expectation of success and need for achievement is an energizing factor. This means that motivation isn’t exactly caused by physiological needs or responses, but rather cognition.  We are shaped by our environment to have needs for competition and mastery. For example, a young boy might be raised to be very athletic. His father might instill in him the values of competitiveness that sticks with the child his whole life, causing him to always succeed in sports. The expectancy theory also brings in the idea of self-fulfilling prophecies. Those who expect to succeed will, while those who don’t think they will do well at something will not.
When a person desires something enough to work long and hard to achieve their goal, they are doing it because it somehow enhances their life and self-esteem. A motive is a specific internal condition involving some kind of arousal that causes one to work toward a goal. 
A social motive is an internal condition that causes people to establish and maintain relationships with other people. Social motives also cause people to establish feelings and views about themselves. A social motive does not need any physiological explanation since it is often based on social and cognitive reasons.  If someone gets straight A’s in school, for instance, they are probably doing it to make their family, friends, teachers, and self proud. Social motives are affected by many different factors including socioeconomic status and personal experience.
Need for Achievement
The desire to do well at something is motivated by a desire to achieve success, mastery, and fulfillment. If something is not a priority then the person has no desire or need to achieve at that particular thing. People learn achievement motivation mostly in their homes while growing up.  People with high needs for success and achievement grew up with parents or teachers that stressed excellence and rewarded hard work.
People who are willing to take risks are more likely to succeed and achieve their goals. Students who are willing to tackle complex problems despite risk of failure are much more likely to succeed in school than students who are to afraid to take chances.
- Type A – These people tend to be high stressed and very active. They have trouble relaxing and doing nothing, and always feel a sense of time urgency. They become irritated when they are slowed down and are more likely to develop high blood pressure or heart problems. Type A people are usually very competitive and like to overachieve, doing many tasks at once.
- Type B – These people do not show the same desire for mastery and success as type A people do. Type B personalities will relax and enjoy doing nothing. They don’t feel rushed or stressed. Type B people can delay their work until the last minute and feel anxiety. Type B people can be achievers but they won’t feel the need to succeed and take on as many tasks as type A people do. Type B people do not have as many health problems.
The cognitive theory of motivation emphasizes the role of thoughts and individual choices regarding life goals and the means of achieving them. Cognitive theory focuses on the idea that thoughts are initiators and determiners of behavior.  The idea is that we all make decisions about what we focus on and put our effort into. Some people don’t care about passing their mid-terms so they don’t study, whereas others might spend many hours studying even though it means foregoing other pleasures. There are a number of cognitive theories relating to motivation, but most all of them focus on figuring out how or why people set goals and achieve them.
Cognitive psychologists believe that if we are aware of our thoughts, behaviors, emotions, and motivations then we can alter them.  As long as we are aware of our thought patterns we should be able to control them and change our behavior. Therapists treating patients heavily believe in the idea that arousal is voluntary and that we have cognitive controls. Through instruction and self-help techniques we are able to alter our behavior by changing thoughts and their expectancies.
Intrinsic and Extrinsic Motivation
When people engage in behaviors that offer no external rewards, just for the sake of doing them, they are called intrinsically motivated behaviors.  Some examples of these behaviors would be doing jigsaw or crossword puzzles. People do intrinsically motivated behaviors to get sensory stimulation and to feel accomplished or like they are mastering a skill. Research has shown that people who are never rewarded for doing a task will often times do the task longer than people who are rewarded for their efforts and then not rewarded anymore. This is because people who are used to receiving external justification for their work will not see the value in the work if they no longer get that external reward. Also, offering rewards for work that somebody already intrinsically enjoyed will result in that person no longer enjoying the activity. Intrinsic motivation can be closely tied to one’s past experiences and self esteem. There are other variables which influence intrinsic motivation, such as the type of reward someone receives or who they are receiving the reward from.
Extrinsic motivation is being motivated to achieve or do something because of external rewards.  Extrinsic rewards can reinforce behavior and provide people with feelings of self-worth or competence. In this way, extrinsic rewards help to boost intrinsic motivation. If extrinsic rewards are given in a way that alters a person’s motivational orientation, however, then intrinsic motivation can be decreased. For the most part, though, extrinsic rewards are good things that can be healthy and helpful for people who are working toward goals.
When people put off doing something that could and should be done in the present time, it is called procrastination.  Those who procrastinate often times rationalize about why they haven’t done their work. For instance, someone who has had three months to write a paper and does it the night before it is due might say tell themselves that they would have done it sooner but they were too busy taking care of their child. By rationalizing, the person won’t feel so bad about not having put as much effort into their work as they could have.
Many procrastinators delay things in the belief that something will happen to keep them from having to do the work, or that it will all magically come into place or get itself done somehow. Sometimes this works, and their problems go away. This reinforces procrastination as a good behavior and leads to a lifestyle of slacking. Everyone procrastinates sometimes in life, but if someone is prone to constant procrastination it can have very serious consequences on their lives. For instance, they may not work to save their failing relationships, or take their car in to a mechanic. All these things add up and make a person’s life negative.
Humanistic theory recognizes how behavior theories can mix together with aspects of the drive, expectancy, and cognitive theories to form solid explanations for motivation and behavior. Humanistic psychologists believe that behavior can be viewed within the framework of a person’s environment and their values.  Their theories try to encompass all of life by focusing on the effect dignity has on individual choice and freedom has on one’s feelings of self-worth. Humanistic psychologists believe that humans are innately good and have the power to develop their potential and seek beauty, truth, and goodness. They believe humans are open, trusting and motivated toward self-actualization. Self-actualization is the process of achieving one’s true nature and full potential.  One of the pioneering humanistic theorists, Abraham Maslow, believed that all people strive to have the following traits :
- Realistically orientated.
- Problem centered.
- Need privacy.
- Are independent.
- Accept themselves for what they are.
- Have an appreciation for people.
- Have spiritual experiences.
- Identify with people.
- Have intimate relationships.
- Are democratic.
- Have a good sense of humor.
- Do not confuse the means with the end.
- Are creative and nonconformist.
- Appreciate the environment.
- Have thoughts that are unconventional and spontaneous.
People who are able to obtain most of these traits are self-actualized. Maslow also created a hierarchy of needs, which explained the motives of people.  Physiological needs were the most important to survival, and are therefore at the bottom of the hierarchy, or pyramid. More complex needs are on the higher levels of the pyramid. People work themselves up the levels of the pyramid by fulfilling one set of needs and then subsequently striving for the next set of needs. If the person is able to satisfy the needs of every level on the pyramid then they have reached self-actualization.
One does not necessarily need to get everything on a level of the pyramid to move up to the next stage, but Maslow believed that having basic physiological and social needs fulfilled helps people to find beauty and self-respect.
Drives and needs are a large part of explaining human behavior and motivation, but we must also take into account the topic of emotions. Emotions are subjective responses that are usually accompanied by a physiological change that is interpreted by the individual, readies the individual toward some action, and has associated with it a change in behavior.  When people get angry they are likely to yell or start a physical fight. If they are sad or depressed they can shy away from the world. When they are happy, humans are often willing to participate in activity and experience new things. Emotions are instinctual and most likely evolved in groups of social animals, where conveying inner feelings were key to survival. Theories have been developed to try and explain how emotions work.
These theories focus on the biological factors that influence emotional change. Most emotions originate in a part of the brain called the limbic system.
- James-Lange Theory – This theory states that people will experience physiological changes and interpret them as emotional states. For instance, people cry first and then feel sad, or smile first and then feel happy, not the other way around.  Our body is essentially creating our emotions.
- Cannon-Bard Theory – This theory states that emotion can’t be determined purely by physiological changes. Instead, emotions are caused by two areas of the brain– the thalamus and cerebral cortex. When we get emotional the thalamus is stimulated, which creates physiological change, and stimulation of the cerebral cortex creates the emotional part of the experience.  Physiological change accompanies emotions, and vice versa.
Cognitive theories mix physiology with interpretation in order to explain emotion.  Most of these theories are extensions of biological theories, and state that emotions can be a bit more complex than what occurs in one person’s body. There may be social or attitude influences that determine emotions. For instance, people can misinterpret the emotions of someone since they are not in their bodies, feeling what they feel. Someone might be screaming and others would think that she is frightened or in pain when in reality she is just very excited about something good that has happened.
These are the main groups of theories that have been proposed to explain human motivation and behavior. This, of course, is not an entire explanation but rather an introductory overview that serves to suffice someone looking for a quick explanation for what motivates us. There are many studies that have been performed and studies that will be performed in the future, all in the pursuit of understanding humans. It is because of the complexity of human behavior that learning about what motivates us, and why, is fascinating.