A variety of reasons. Some people are simply judgmental because that's their own perceptions of things. The reasons are complicated and varied to be certain. Usually it's learned behavior from siblings, parents, friends, and other people. Personalities develop throughout childhood into adulthood and basically, our life experiences and genetics determine our personalities. This explains why your sister is judgmental and criticizes everything. It could also be becuase she's simply depressed. Typically, depressed people tend to chronically complain about anything and everything. Here's a website link: http://allpsych.com/psychology101/personality.html that discusses clinical depression & personality development as follows:: "Introduction to Development, Personality, and Stage Theories When discussing any type of development, most theorist break it down into specific stages. These stages are typically progressive. In other words, you must pass through one stage before you can get to the next. Think about how you learned to run; first you had to learn to crawl, then you could learn to walk, and finally you could develop the skills needed to run. Without the first two stages, running would be an impossibility. In this chapter we will discuss the most prominent stage theories in regard to motor and cognitive, social development, development, and moral development. Most of these stage theories are progressive, although in some, such as Erikson's psychosocial and Freud's psychosexual, a person can fail to complete the stage while still continuing. This failure, however, will result in difficulties later in life according to the theories. The following offers an overview of development according to the principles of psychology. Chapter 3: Personality Development Section 1: Introduction to Development, Personality, and Stage Theories Section 2: Motor and Cognitive Development Section 3: Erikson’s Stages of Psychosocial Development Section 4: Freud’s Stages of Psychosexual Development Section 5: Freud's Structural and Typographical Model Section 6: Freud's Ego Defense Mechanisms Section 7: Kohlberg’s Stages of Moral Development -------------------------------------------------------------------------------- Motor Development in Infancy and Childhood Most infants develop motor abilities in the same order and at approximately the same age. In this sense, most agree that these abilities are genetically preprogrammed within all infants. The environment does play a role in the development, with an enriched environment often reducing the learning time and an impoverished one doing the opposite. The following chart delineates the development of infants in sequential order. The ages shown are averages and it is normal for these to vary by a month or two in either direction. 2 months – able to lift head up on his own 3 months – can roll over 4 months – can sit propped up without falling over 6 months – is able to sit up without support 7 months – begins to stand while holding on to things for support 9 months – can begin to walk, still using support 10 months – is able to momentarily stand on her own without support 11 months – can stand alone with more confidence 12 months – begin walking alone without support 14 months – can walk backward without support 17 months – can walk up steps with little or no support 18 months – able to manipulate objects with feet while walking, such as kicking a ball Cognitive Development in Children Probably the most cited theory in the cognitive development in children is Jean Piaget (1896-1980). As with all stage theories, Piaget’s Theory of Cognitive Development maintains that children go through specific stages as their intellect and ability to see relationships matures. These stages are completed in a fixed order with all children, even those in other countries. The age range, however can vary from child to child. Sensorimotor Stage. This stage occurs between the ages of birth and two years of age, as infants begin to understand the information entering their sense and their ability to interact with the world. During this stage, the child learns to manipulate objects although they fail to understand the permanency of these objects if they are not within their current sensory perception. In other words, once an object is removed from the child’s view, he or she is unable to understand that the object still exists. The major achievement during this stage is that of Object Permanency, or the ability to understand that these objects do in fact continue to exist. This includes his ability to understand that when mom leaves the room, she will eventually return, resulting in an increased sense of safety and security. Object Permanency occurs during the end of this stage and represents the child’s ability to maintain a mental image of the object (or person) without the actual perception. Preoperational Stage. The second stage begins after Object Permanency is achieved and occurs between the ages of two to seven years of age. During this stage, the development of language occurs at a rapid pace. Children learn how to interact with their environment in a more complex manner through the use of words and images. This stage is marked by Egocentrism, or the child’s belief that everyone sees the world the same way that she does. The fail to understand the differences in perception and believe that inanimate objects have the same perceptions they do, such as seeing things, feeling, hearing and their sense of touch. A second important factor in this stage is that of Conservation, which is the ability to understand that quantity does not change if the shape changes. In other words, if a short and wide glass of water is poured into a tall and thin glass. Children in this stage will perceive the taller glass as having more water due only because of it’s height. This is due to the children’s inability to understand reversibility and to focus on only one aspect of a stimulus (called centration), such as height, as opposed to understanding other aspects, such as glass width. Concrete Operations Stage. Occurring between ages 7 and about 12, the third stage of cognitive development is marked by a gradual decrease in centristic thought and the increased ability to focus on more than one aspect of a stimulus. They can understand the concept of grouping, knowing that a small dog and a large dog are still both dogs, or that pennies, quarters, and dollar bills are part of the bigger concept of money. They can only apply this new understanding to concrete objects ( those they have actually experienced). In other words, imagined objects or those they have not seen, heard, or touched, continue to remain somewhat mystical to these children, and abstract thinking has yet to develop. Formal Operations Stage. In the final stage of cognitive development (from age 12 and beyond), children begin to develop a more abstract view of the world. They are able to apply reversibility and conservation to both real and imagined situations. They also develop an increased understanding of the world and the idea of cause and effect. By the teenage years, they are able to develop their own theories about the world. This stage is achieved by most children, although failure to do so has been associated with lower intelligence. Erikson’s Stages of Psychosocial Development Like Piaget, Erik Erikson (1902-1994) maintained that children develop in a predetermined order. Instead of focusing on cognitive development, however, he was interested in how children socialize and how this affects their sense of self. Erikson’s Theory of Psychosocial Development has eight distinct stage, each with two possible outcomes. According to the theory, successful completion of each stage results in a healthy personality and successful interactions with others. Failure to successfully complete a stage can result in a reduced ability to complete further stages and therefore a more unhealthy personality and sense of self. These stages, however, can be resolved successfully at a later time. Trust Versus Mistrust. From ages birth to one year, children begin to learn the ability to trust others based upon the consistency of their caregiver(s). If trust develops successfully, the child gains confidence and security in the world around him and is able to feel secure even when threatened. Unsuccessful completion of this stage can result in an inability to trust, and therefore an sense of fear about the inconsistent world. It may result in anxiety, heightened insecurities, and an over feeling of mistrust in the world around them. Autonomy vs. Shame and Doubt. Between the ages of one and three, children begin to assert their independence, by walking away from their mother, picking which toy to play with, and making choices about what they like to wear, to eat, etc. If children in this stage are encouraged and supported in their increased independence, they become more confident and secure in their own ability to survive in the world. If children are criticized, overly controlled, or not given the opportunity to assert themselves, they begin to feel inadequate in their ability to survive, and may then become overly dependent upon others, lack self-esteem, and feel a sense of shame or doubt in their own abilities. Initiative vs. Guilt. Around age three and continuing to age six, children assert themselves more frequently. They begin to plan activities, make up games, and initiate activities with others. If given this opportunity, children develop a sense of initiative, and feel secure in their ability to lead others and make decisions. Conversely, if this tendency is squelched, either through criticism or control, children develop a sense of guilt. They may feel like a nuisance to others and will therefore remain followers, lacking in self-initiative. Industry vs. Inferiority. From age six years to puberty, children begin to develop a sense of pride in their accomplishments. They initiate projects, see them through to completion, and feel good about what they have achieved. During this time, teachers play an increased role in the child’s development. If children are encouraged and reinforced for their initiative, they begin to feel industrious and feel confident in their ability to achieve goals. If this initiative is not encouraged, if it is restricted by parents or teacher, then the child begins to feel inferior, doubting his own abilities and therefore may not reach his potential. Identity vs. Role Confusion. During adolescence, the transition from childhood to adulthood is most important. Children are becoming more independent, and begin to look at the future in terms of career, relationships, families, housing, etc. During this period, they explore possibilities and begin to form their own identity based upon the outcome of their explorations. This sense of who they are can be hindered, which results in a sense of confusion ("I don’t know what I want to be when I grow up") about themselves and their role in the world. Intimacy vs. Isolation. Occurring in Young adulthood, we begin to share ourselves more intimately with others. We explore relationships leading toward longer term commitments with someone other than a family member. Successful completion can lead to comfortable relationships and a sense of commitment, safety, and care within a relationship. Avoiding intimacy, fearing commitment and relationships can lead to isolation, loneliness, and sometimes depression. Generativity vs. Stagnation. During middle adulthood, we establish our careers, settle down within a relationship, begin our own families and develop a sense of being a part of the bigger picture. We give back to society through raising our children, being productive at work, and becoming involved in community activities and organizations. By failing to achieve these objectives, we become stagnant and feel unproductive. Ego Integrity vs. Despair. As we grow older and become senior citizens, we tend to slow down our productivity, and explore life as a retired person. It is during this time that we contemplate our accomplishments and are able to develop integrity if we see ourselves as leading a successful life. If we see our lives as unproductive, feel guilt about our pasts, or feel that we did not accomplish our life goals, we become dissatisfied with life and develop despair, often leading to depression and hopelessness. Freud’s Stages of Psychosexual Development Sigmund Freud (1856-1939) is probably the most well known theorist when it comes to the development of personality. Freud’s Stages of Psychosexual Development are, like other stage theories, completed in a predetermined sequence and can result in either successful completion or a healthy personality or can result in failure, leading to an unhealthy personality. This theory is probably the most well known as well as the most controversial, as Freud believed that we develop through stages based upon a particular erogenous zone. During each stage, an unsuccessful completion means that a child becomes fixated on that particular erogenous zone and either over– or under-indulges once he or she becomes an adult. Oral Stage (Birth to 18 months). During the oral stage, the child if focused on oral pleasures (sucking). Too much or too little gratification can result in an Oral Fixation or Oral Personality which is evidenced by a preoccupation with oral activities. This type of personality may have a stronger tendency to smoke, drink alcohol, over eat, or bite his or her nails. Personality wise, these individuals may become overly dependent upon others, gullible, and perpetual followers. On the other hand, they may also fight these urges and develop pessimism and aggression toward others. Anal Stage (18 months to three years). The child’s focus of pleasure in this stage is on eliminating and retaining feces. Through society’s pressure, mainly via parents, the child has to learn to control anal stimulation. In terms of personality, after effects of an anal fixation during this stage can result in an obsession with cleanliness, perfection, and control (anal retentive). On the opposite end of the spectrum, they may become messy and disorganized (anal expulsive). Phallic Stage (ages three to six). The pleasure zone switches to the genitals. Freud believed that during this stage boy develop unconscious sexual desires for their mother. Because of this, he becomes rivals with his father and sees him as competition for the mother’s affection. During this time, boys also develop a fear that their father will punish them for these feelings, such as by castrating them. This group of feelings is known as Oedipus Complex ( after the Greek Mythology figure who accidentally killed his father and married his mother). Later it was added that girls go through a similar situation, developing unconscious sexual attraction to their father. Although Freud Strongly disagreed with this, it has been termed the Electra Complex by more recent psychoanalysts. According to Freud, out of fear of castration and due to the strong competition of his father, boys eventually decide to identify with him rather than fight him. By identifying with his father, the boy develops masculine characteristics and identifies himself as a male, and represses his sexual feelings toward his mother. A fixation at this stage could result in sexual deviancies (both overindulging and avoidance) and weak or confused sexual identity according to psychoanalysts. Latency Stage (age six to puberty). It’s during this stage that sexual urges remain repressed and children interact and play mostly with same sex peers. Genital Stage (puberty on). The final stage of psychosexual development begins at the start of puberty when sexual urges are once again awakened. Through the lessons learned during the previous stages, adolescents direct their sexual urges onto opposite sex peers, with the primary focus of pleasure is the genitals. Topographical Model Freud believed that the majority of what we experience in our lives, the underlying emotions, beliefs, feelings, and impulses are not available to us at a conscious level. He believed that most of what drives us is buried in our unconscious. If you remember the Oedipus and Electra Complex, they were both pushed down into the unconscious, out of our awareness due to the extreme anxiety they caused. While buried there, however, they continue to impact us dramatically according to Freud. The role of the unconscious is only one part of the model. Freud also believed that everything we are aware of is stored in our conscious. Our conscious makes up a very small part of who we are. In other words, at any given time, we are only aware of a very small part of what makes up our personality; most of what we are is buried and inaccessible. The final part is the preconscious or subconscious. This is the part of us that we can access if prompted, but is not in our active conscious. Its right below the surface, but still buried somewhat unless we search for it. Information such as our telephone number, some childhood memories, or the name of your best childhood friend is stored in the preconscious. Because the unconscious is so large, and because we are only aware of the very small conscious at any given time, this theory has been likened to an iceberg, where the vast majority is buried beneath the water's surface. The water, by the way, would represent everything that we are not aware of, have not experienced, and that has not been integrated into our personalities, referred to as the nonconscious. Ego Defense Mechanisms We stated earlier that the ego's job was to satisfy the id's impulses, not offend the moralistic character of the superego, while still taking into consideration the reality of the situation. We also stated that this was not an easy job. Think of the id as the 'devil on your shoulder' and the superego as the 'angel of your shoulder.' We don't want either one to get too strong so we talk to both of them, hear their perspective and then make a decision. This decision is the ego talking, the one looking for that healthy balance. Before we can talk more about this, we need to understand what drives the id, ego, and superego. According to Freud, we only have two drives; sex and aggression. In other words, everything we do is motivated by one of these two drives. Sex, also called Eros or the Life force, represents our drive to live, prosper, and produce offspring. Aggression, also called Thanatos or our Death force, represents our need to stay alive and stave off threats to our existence, our power, and our prosperity. Now the ego has a difficult time satisfying both the id and the superego, but it doesn't have to do so without help. The ego has some tools it can use in its job as the mediator, tools that help defend the ego. These are called Ego Defense Mechanisms or Defenses. When the ego has a difficult time making both the id and the superego happy, it will employ one or more of these defenses: DEFENSE DESCRIPTION EXAMPLE denial arguing against an anxiety provoking stimuli by stating it doesn't exist denying that your physician's diagnosis of cancer is correct and seeking a second opinion displacement taking out impulses on a less threatening target slamming a door instead of hitting as person, yelling at your spouse after an argument with your boss intellectualization avoiding unacceptable emotions by focusing on the intellectual aspects focusing on the details of a funeral as opposed to the sadness and grief projection placing unacceptable impulses in yourself onto someone else when losing an argument, you state "You're just Stupid;" homophobia rationalization supplying a logical or rational reason as opposed to the real reason stating that you were fired because you didn't kiss up the the boss, when the real reason was your poor performance reaction formation taking the opposite belief because the true belief causes anxiety having a bias against a particular race or culture and then embracing that race or culture to the extreme regression returning to a previous stage of development sitting in a corner and crying after hearing bad news; throwing a temper tantrum when you don't get your way repression pulling into the unconscious forgetting sexual abuse from your childhood due to the trauma and anxiety sublimation acting out unacceptable impulses in a socially acceptable way sublimating your aggressive impulses toward a career as a boxer; becoming a surgeon because of your desire to cut; lifting weights to release 'pent up' energy suppression pushing into the unconscious trying to forget something that causes you anxiety Ego defenses are not necessarily unhealthy as you can see by the examples above. In face, the lack of these defenses, or the inability to use them effectively can often lead to problems in life. However, we sometimes employ the defenses at the wrong time or overuse them, which can be equally destructive. Kohlberg’s Stages of Moral Development Although it has been questioned as to whether it applied equally to different genders and different cultures, Kohlberg’s (1973) stages of moral development is the most widely cited. It breaks our development of morality into three levels, each of which is divided further into two stages: Preconventional Level (up to age nine): ~Self Focused Morality~ 1. Morality is defined as obeying rules and avoiding negative consequences. Children in this stage see rules set, typically by parents, as defining moral law. 2. That which satisfies the child’s needs is seen as good and moral. Conventional Level (age nine to adolescence): ~Other Focused Morality~ 3. Children begin to understand what is expected of them by their parents, teacher, etc. Morality is seen as achieving these expectations. 4. Fulfilling obligations as well as following expectations are seen as moral law for children in this stage. Postconventional Level (adulthood): ~Higher Focused Morality~ 5. As adults, we begin to understand that people have different opinions about morality and that rules and laws vary from group to group and culture to culture. Morality is seen as upholding the values of your group or culture. 6. Understanding your own personal beliefs allow adults to judge themselves and others based upon higher levels of morality. In this stage what is right and wrong is based upon the circumstances surrounding an action. Basics of morality are the foundation with independent thought playing an important role. Introduction to Learning Theory and Behavioral Psychology Learning can be defined as the process leading to relatively permanent behavioral change or potential behavioral change. In other words, as we learn, we alter the way we perceive our environment, the way we interpret the incoming stimuli, and therefore the way we interact, or behave. John B. Watson (1878-1958) was the first to study how the process of learning affects our behavior, and he formed the school of thought known as Behaviorism. The central idea behind behaviorism is that only observable behaviors are worthy of research since other abstraction such as a person’s mood or thoughts are too subjective. This belief was dominant in psychological research in the United Stated for a good 50 years. Perhaps the most well known Behaviorist is B. F. Skinner (1904-1990). Skinner followed much of Watson’s research and findings, but believed that internal states could influence behavior just as external stimuli. He is considered to be a Radical Behaviorist because of this belief, although nowadays it is believed that both internal and external stimuli influence our behavior. Behavioral Psychology is basically interested in how our behavior results from the stimuli both in the environment and within ourselves. They study, often in minute detail, the behaviors we exhibit while controlling for as many other variables as possible. Often a grueling process, but results have helped us learn a great deal about our behaviors, the effect our environment has on us, how we learn new behaviors, and what motivates us to change or remain the same. Classical and Operant Conditioning Classical Conditioning. One important type of learning, Classical Conditioning, was actually discovered accidentally by Ivan Pavlov (1849-1936). Pavlov was a Russian physiologist who discovered this phenomenon while doing research on digestion. His research was aimed at better understanding the digestive patterns in dogs. During his experiments, he would put meat powder in the mouths of dogs who had tubes inserted into various organs to measure bodily responses. What he discovered was that the dogs began to salivate before the meat powder was presented to them. Then, the dogs began to salivate as soon as the person feeding them would enter the room. He soon began to gain interest in this phenomenon and abandoned his digestion research in favor of his now famous Classical Conditioning study. Basically, the findings support the idea that we develop responses to certain stimuli that are not naturally occurring. When we touch a hot stove, our reflex pulls our hand back. It does this instinctually, no learning involved. It is merely a survival instinct. But why now do some people, after getting burned, pull their hands back even when the stove is not turned on? Pavlov discovered that we make associations which cause us to generalize our response to one stimuli onto a neutral stimuli it is paired with. In other words, hot burner = ouch, stove = burner, therefore, stove = ouch. Pavlov began pairing a bell sound with the meat powder and found that even when the meat powder was not presented, the dog would eventually begin to salivate after hearing the bell. Since the meat powder naturally results in salivation, these two variables are called the unconditioned stimulus (UCS) and the unconditioned response (UCR), respectively. The bell and salivation are not naturally occurring; the dog was conditioned to respond to the bell. Therefore, the bell is considered the conditioned stimulus (CS), and the salivation to the bell, the conditioned response (CR). Many of our behaviors today are shaped by the pairing of stimuli. Have you ever noticed that certain stimuli, such as the smell of a cologne or perfume, a certain song, a specific day of the year, results in fairly intense emotions? It's not that the smell or the song are the cause of the emotion, but rather what that smell or song has been paired with...perhaps an ex-boyfriend or ex-girlfriend, the death of a loved one, or maybe the day you met you current husband or wife. We make these associations all the time and often don’t realize the power that these connections or pairings have on us. But, in fact, we have been classically conditioned. Operant Conditioning. Another type of learning, very similar to that discussed above, is called Operant Conditioning. The term "Operant" refers to how an organism operates on the environment, and hence, operant conditioning comes from how we respond to what is presented to us in our environment. It can be thought of as learning due to the natural consequences of our actions. Let's explain that a little further. The classic study of Operant Conditioning involved a cat who was placed in a box with only one way out; a specific area of the box had to be pressed in order for the door to open. The cat initially tries to get out of the box because freedom is reinforcing. In its attempt to escape, the area of the box is triggered and the door opens. The cat is now free. Once placed in the box again, the cat will naturally try to remember what it did to escape the previous time and will once again find the area to press. The more the cat is placed back in the box, the quicker it will press that area for its freedom. It has learned, through natural consequences, how to gain the reinforcing freedom. We learn this way every day in our lives. Imagine the last time you made a mistake; you most likely remember that mistake and do things differently when the situation comes up again. In that sense, you’ve learned to act differently based on the natural consequences of your previous actions. The same holds true for positive actions. If something you did results in a positive outcome, you are likely to do that same activity again. Reinforcement The term reinforce means to strengthen, and is used in psychology to refer to anything stimulus which strengthens or increases the probability of a specific response. For example, if you want your dog to sit on command, you may give him a treat every time he sits for you. The dog will eventually come to understand that sitting when told to will result in a treat. This treat is reinforcing because he likes it and will result in him sitting when instructed to do so. This is a simple description of a reinforcer (Skinner, 1938), the treat, which increases the response, sitting. We all apply reinforcers everyday, most of the time without even realizing we are doing it. You may tell your child "good job" after he or she cleans their room; perhaps you tell your partner how good he or she look when they dress up; or maybe you got a raise at work after doing a great job on a project. All of these things increase the probability that the same response will be repeated. There are four types of reinforcement: positive, negative, punishment, and extinction. We’ll discuss each of these and give examples. Positive Reinforcement. The examples above describe what is referred to as positive reinforcement. Think of it as adding something in order to increase a response. For example, adding a treat will increase the response of sitting; adding praise will increase the chances of your child cleaning his or her room. The most common types of positive reinforcement or praise and rewards, and most of us have experienced this as both the giver and receiver. Negative Reinforcement. Think of negative reinforcement as taking something negative away in order to increase a response. Imagine a teenager who is nagged by his mother to take out the garbage week after week. After complaining to his friends about the nagging, he finally one day performs the task and to his amazement, the nagging stops. The elimination of this negative stimulus is reinforcing and will likely increase the chances that he will take out the garbage next week. Punishment. Punishment refers to adding something aversive in order to decrease a behavior. The most common example of this is disciplining (e.g. spanking) a child for misbehaving. The reason we do this is because the child begins to associate being punished with the negative behavior. The punishment is not liked and therefore to avoid it, he or she will stop behaving in that manner. Extinction. When you remove something in order to decrease a behavior, this is called extinction. You are taking something away so that a response is decreased. Research has found positive reinforcement is the most powerful of any of these. Adding a positive to increase a response not only works better, but allows both parties to focus on the positive aspects of the situation. Punishment, when applied immediately following the negative behavior can be effective, but results in extinction when it is not applied consistently. Punishment can also invoke other negative responses such as anger and resentment. Reinforcement Schedules Know that we understand the four types of reinforcement, we need to understand how and when these are applied (Ferster & Skinner, 1957). For example, do we apply the positive reinforcement every time a child does something positive? Do we punish a child every time he does something negative? To answer these questions, you need to understand the schedules of reinforcement. Applying one of the four types of reinforcement every time the behavior occurs (getting a raise after every successful project or getting spanked after every negative behavior) is called a Continuous Schedule. Its continuous because the application occurs after every project, behavior, etc. This is the best approach when using punishment. Inconsistencies in the punishment of children often results in confusion and resentment. A problem with this schedule is that we are not always present when a behavior occurs or may not be able to apply the punishment. There are two types of continuous schedules: Fixed Ratio. A fixed ratio schedule refers to applying the reinforcement after a specific number of behaviors. Spanking a child if you have to ask him three times to clean his room is an example. The problem is that the child (or anyone for that matter) will begin to realize that he can get away with two requests before he has to act. Therefore, the behavior does not tend to change until right before the preset number. Fixed Interval. Applying the reinforcer after a specific amount of time is referred to as a fixed interval schedule. An example might be getting a raise every year and not in between. A major problem with this schedule is that people tend to improve their performance right before the time period expires so as to "look good" when the review comes around. When reinforcement is applied on an irregular basis, they are called variable schedules. Variable Ratio. This refers to applying a reinforcer after a variable number of responses. Variable ratio schedules have been found to work best under many circumstances and knowing an example will explain why. Imagine walking into a casino and heading for the slot machines. After the third coin you put in, you get two back. Two more and you get three back. Another five coins and you receive two more back. How difficult is it to stop playing? Variable Interval. Reinforcing someone after a variable amount of time is the final schedule. If you have a boss who checks your work periodically, you understand the power of this schedule. Because you don’t know when the next ‘check-up’ might come, you have to be working hard at all times in order to be ready. In this sense, the variable schedules are more powerful and result in more consistent behaviors. This may not be as true for punishment since consistency in the application is so important, but for all other types of reinforcement they tend to result in stronger responses. " source: http://allpsych.com/psychology101/personality.html Symptoms of depression: " you are depressed at the moment some of the following symptoms may sound familiar: You feel miserable and sad. You feel exhausted a lot of the time with no energy . You feel as if even the smallest tasks are sometimes impossible. You seldom enjoy the things that you used to enjoy-you may be off sex or food or may 'comfort eat' to excess. You feel very anxious sometimes. You don't want to see people or are scared to be left alone. Social activity may feel hard or impossible. You find it difficult to think clearly. You feel like a failure and/or feel guilty a lot of the time. You feel a burden to others. You sometimes feel that life isn't worth living. You can see no future. There is a loss of hope. You feel all you've ever done is make mistakes and that's all that you ever will do. You feel irritable or angry more than usual. You feel you have no confidence. You spend a lot of time thinking about what has gone wrong, what will go wrong or what is wrong about yourself as a person. You may also feel guilty sometimes about being critical of others (or even thinking critically about them). You feel that life is unfair. You have difficulty sleeping or wake up very early in the morning and can't sleep again. You seem to dream all night long and sometimes have disturbing dreams. You feel that life has/is 'passing you by.' You may have physical aches and pains which appear to have no physical cause, such as back pain." source: http://www.clinical-depression.co.uk/Depression_Information/symptoms.htm I hope this helps to explain personality development & clinical depression, overall, which can be used to explain your sister's critciisms of others.

Here is some information which has relevance. I gave this answer to the question: "What are some tell tale signs that someone is cheating?" . "Another possible indicator is the "strained accusation". Sometimes a guilty party accuses someone else of the same type or category of deed. The accusation is strained, but yet could seem believable. In other words, the accuser is guilty of the 'sin' or a similar type 'sin'. This often can be observed with criminals who get upset about something supposedly done to them of which they themselves are also guilty of having done. An example: "Where have you been?...I think you are having an affair with so-and-so...." when your routine has not changed a bit from the normal. It could be an indicator." It is actually very common to see these strained accusations in areas other than "cheating". Extremely critical people who strain to grasp for 'reasons' of how someone else is immoral in some way are often culprits of hidden, undisclosed immoral deeds. "He is always mean to me. He always says these mean, mean, nasty statements... ...and he did this other mean thing... ...and there was the time he did this...." The accuser here probably has a bag full of times of being mean. Actually, you can take this one step further. You have probably noticed that some people are very critical in general disposition and easily find faults with another (or...ha!... an answer on this site). Typically, the more critical and fault-finding (without also viewing the plus sides or understanding the viewpoint) that a person is, the less affinity or "liking" for other people that person has. The more critical the individual is, the colder the individual is. The criticalness may not be expressed and you see this with the "silent type" of individual. Criticalness which typically is strained also means that a person has an "incorrect estimation" of things, (i.e. evaluations are poor because the understanding or the whole picture of things is not fully looked at). But a key element here is that the hyper-critical person has done stuff to others which are less than noble or pure. For example, a cold-blooded person is critical and has by that very nature done cold and heartless things to others. It could be rudeness, invalidation, nullification, slander, gossip, verbal abuse, bad temper, "slams", physically hurting another, stealing, crimes, etc. It is an unfeeling approach to others. This nature does not include a full understanding. In short, "sins" or misdeeds against others make a person more critical in nature and also make a person partially blind in being able to view the full perspective. Another example, is that you will see the "super-critics" on this website demean the answers of others without offering a full conceptual answer of their own. And also they are not really motivated towards seeing a betterment of well-being of others. The purpose of a strained-critic is not really to improve conditions, but rather to make less of others...(which supposedly would then elevate self after having done things which one should not really be proud of). This kind of routine of not making others feel good or genuinely trying to assist others, of course, has been going on for awhile...the person has this general type of misdeed history...and also, now, the super-criticalness. Always know that the strained-critic has not been nice to others and has not been a "good boy". Another thing that I should mention: Chemicals and/or toxins. There are many chemicals, drugs, preservatives, metals, and other foreign substances which can affect a person's demeaner. Many substances have a tendency to make a person more easily agitated, more irritable, more aggressively hostile or anxious. You can test this for yourself. If someone you know starts taking a medication or drug, watch to see if their behavior slightly starts to change over the next few weeks. This aggression is easily observed with many street drugs such as amphetamines. You can test it on yourself with different substances. Some things, even sugar or aspirin, may have an effect on your outlook a day or two after taking them. I don't recommend this: You can certainly see a resulting agitation if you take a strong flouride treatment for your teeth. It is a toxic substance. That is why toothpaste is not supposed to be eaten (plus it has soap and other things in it). Flouride compounds are sometimes found in psych drugs. Anyway, my point here is that if your sister is regularly taking any kind of drug or unhealthy substance, it can affect her demeaner. It could make her more mean-spirited. By the way, this isn't a strange idea. It is just common sense. When a person's body isn't doing well or is achy or sick or polluted with foreign substances, the person then feels gripey and unpleasant. It is that simple. When you are sick physically, you probably have less tolerance for some things.