Psychological projection—you may have heard of it before. Someone, with their self-qualified overconfident wisdom, may have even tried to pin that diagnosis on you. The concept is often used pejoratively. Projection activates itself when the human ego needs a defense against unconscious whims, urges, and compulsions (both positive and negative). When your unconscious feelings try to use your conscious beliefs as a sparring partner, don’t be surprised when you find yourself trying to externalize the issues you know exist within. It’s always society’s fault and never yours that you are who you are. Right? Since projection involves denying certain qualities within yourself by assigning them to others, maybe we can say that blame-shifting is either synonymous or a close relative. 
A habitually rude person can also habitually accuse others of being rude. Have you ever witnessed someone like this? That doubles the rudeness, doesn’t it? Hypocrisy might be the first word to come to mind. Even Jesus addressed something like this in Matthew 7:3-5 “Why do you look at the speck of sawdust in your brother’s eye and pay no attention to the plank in your own eye? 4 How can you say to your brother, ‘Let me take the speck out of your eye,’ when all the time there is a plank in your own eye? 5 You hypocrite first take the plank out of your own eye, and then you will see clearly to remove the speck from your brother’s eye.”
The feeling of “it’s not me, it’s them” can be a very powerful and persuasive feeling that helps you deny and repress your problem instead of directly confronting it. Your friable ego may find projection to be an easy weapon against your internal enemies but will not be quick to recognize dissociation as a cost, especially when dissociative identity disorder is involved.  Personal and political calamities are said to incite psychological projection within normal people, but we can expect to witness this phenomenon more often in narcissistic personality disorder and borderline personality disorder when they operate at a primitive level. 
Projection is a concept that traces back to Sigmund Freud in the 1890s and his discussions on myth, religion, and primitive thinking. I interpret Freud as saying that projection is a regression into savage, primitive, animistic, childlike behavior. Projection is elementary in self-development. Perhaps the best metaphor for describing projection is to say that it is like a piece of technology throwing an image onto a screen. 
In the early 1900s, Freud discussed projection in his psychoanalysis lectures that also discussed the nature of neuroses, melancholia, narcissistic identification, delusions, paranoia and obsessions. Now, none of this is meant to imply that if you are inveterately projecting your unwanted parts onto others you must have a mental health disorder. But it seems rather apparent to me that Freud regarded projection as sharing some topography and dynamics with the aforesaid afflictions. I think it was Freud who first informed us that projection exists in connection with the unconscious and sets itself up in the ego. Your ego is treated like the object that you attach yourself to or repudiate. The ego suffers collateral damage as we act upon aggression and vengeance aimed at loved and hated objects. 
We have some interesting examples of psychological projection spanning throughout human history. You may remember having read about The Salem Witch Trials in high school; at least I do. Psychological projection of repressed aggression has been asseverated by John Demos as cause for the mental thralldom that the girls suffered in Salem in the Province of Massachusetts Bay of 1962.  In case you are unfamiliar with the story, let me express this quick synopsis:
Several girls who were exhibiting bizarre behaviors in Salem in the Province of Massachusetts Bay of 1692 blamed a local slave, Tituba, and two other females of spellbinding them. While being held under duress, Tituba confessed to using witchcraft and knowing of other guilty parties. A massive witch-hunt ensued, which helped the Puritans justify their personal vendetta against the colonists who did not abide by their religious convictions. Many innocent people were imprisoned and killed in that old village. Historians believe the accused “were victims of mob mentality, mass hysteria and scapegoating.” The story has been infamously used as a testament to the consequences of collective frenzied behavior, fearmongering, religious intolerance, and non-evidence-based thinking that can creep into our criminal justice system. 
A lot happened in that mishmash, and maybe you can imagine the indignation you probably would have felt while being accused of something you did not do. Imagine being indicted because of the superstitious twaddle people believe in and there was almost nothing you could do to avoid it in the first place. Can you imagine the racing thoughts you would experience? Imagine every eternal moment of helplessness and all the things you would have to say to protect yourself back in the 1600s when people did not operate on the innocent-until-proven-guilty principle? You would need to think quickly and likely could not avoid being clumsy. Not much time would be available for assorting all your arguments that could dissuade your detractors, because your mind would be overwhelmingly clouded, and you would constantly feel tempted to make up lies and believe them yourself, wholeheartedly. All eyes feasting on you would have to be diverted by your blaming others.
In everyday living here in modern America and the Western world, we may not be witnessing witch-hunts, but quite often life can make you feel like there is a witch-hunt against you.
A romantic partner can make you feel like a dozen arrows are pointing at you as he/she bombards you with protests. Maybe she/he is accurate with those accusations, maybe not. To cope with the stress and anxiety caused by invasive or alarming thoughts, feelings, and/or impulses, maybe he/she is vomiting them onto you to feel untrammeled from his/her own mental traps. Maybe you are doing this in response to his/her verifiable criticisms and complaints. Who knows? Just suggesting all the various possibilities makes me think a lot of chatter, garbling and mayhem must be happening. I can imagine that a lot of the fleeting thoughts would occur:
‘I don’t feel that’
‘I don’t think this’
‘I never said that, instead you said that’
‘I am feeling this anger, because you want me to feel angry.’
‘My reckless driving was caused by your provoking it.’
Sometimes, we can be quite unaware of our worst fears about ourselves. We can see them in our partners, and not totally realize why we are seeing them. It becomes especially hard to diagnose the problem when we are struggling to articulate what we are seeing and fearing. The result is oftentimes increased confusion and anger.
As the projector, your accusatory goal can cause you to waste a lot of time as you fixate on the wrong things and refuse to realize what is happening in the moment. Putting your partner in a false role muddies your communication with him/her. Think about how unreasonable you might sound to your partner if your words are a shining example of the load of bosh you blame him/her for. 
Infidelity may be a great example. If you are subconsciously attracted to someone else outside of your relationship, and you have refused to admit this to yourself, you may feel paranoid about your partner cheating and so you chide him/her every time they open their text messaging inbox to talk to others. Really, the infidelity is on you, but that seems to be too unacceptable. You see? Trying to externalize what exists on the inside, again.
Psychological projection can be hard to escape when you are facing ambivalent emotions. If you believe that vacationing away from family responsibilities is usually selfish, but the responsibilities of your family life have become almost insufferable, thereby making you want to escape, you might try to cope with this by becoming a nudnik to your partner whenever he/she takes an occasional break. Again, you greatly imperil yourself with projection whenever you try to shake off parts of yourself.
Climbing the mountain to overcome psychological projection may appear to be not for the faint of heart. But I think it is attainable for everyone.
The force of evolution has not been totally kind to humanity. So, have mercy on yourself as you try to manage your imperfections. To demonstrate why, perhaps I can say that the human brain that acts as an information-processor is analogous to the first law of thermodynamics or the conservation of energy (matter and energy are neither created nor destroyed). Nevertheless, information that enters the brain also reduces in quality and disappears. We forget about what we hear, see, taste, smell and touch all the time, though information is always arguably recoverable. 
Stimuli from the environment that enters via our senses are energy-based when it is encoded into brain activity. For instance, you have layers of retinal nerve cells that fire in response to the intensity and color of light. Photons hit the back of the eye. And you experience a thought. Perhaps you have never thought of your thoughts as being measurable materials, because you can only feel them and speak and write about them. They are limited in power and scope. 
As an organ, the brain’s sole connection with outside reality is through the self’s limited five senses. The brain mostly lives in fantasy, despite how much you probably want to disagree and say you are realistic about nearly everything you say and do. You can only input fragments from your environment. You cannot be the panoramic spectator that you wish to be. And to make matters worse, you are not even aware of all the fragments you are inputting constantly. Most of the information gets drowned out by the noise and registers outside your awareness. Raw sensory data is adulterated by your mind, culture, relationships, tunnel vision, faulty compartmentalization, anxiety, ego, and a smorgasbord of other things. No doubt, you cannot be totally to blame for not seeing everything. The things about “you” that are mistaken for “me” and “others” makes up the defense mechanism against uncomfortable feelings, because the brain cannot afford to have its bandwidth deluged with too much information. 
So, do not panic! Psychological projection has preyed on us all at one time or another. No one is immune to it. So, have mercy on yourself and your partner, your family, and friends. Use your projection mistakes as opportunities to grow, to practice more self-awareness, and to strengthen your bond with your loved ones.
 Sigmund Freud, Case Histories II (PFL 9) p. 132https://en.wikipedia.org/wiki/Psychological_projection#cite_note-1
 Trauma and PTSD: Aftermaths of the WTC Disaster – An Interview With Yael Danieli, Ph.D. Medscape General Medicine. 2001;3(4) https://www.medscape.com/viewarticle/408692
 Taylor & Francis Online, Journal of Child Psychotherapy, Anne Hurry, Jack Novick &Kerry Kelly Novick, Published online: 24 Sep 2007https://www.tandfonline.com/doi/pdf/10.1080/00754177608254963?needAccess=true
 Introductory Lectures on Psychoanalysis, Sigmund Freud, Translated and Edited by James Strachey, With a Biographical Introduction by Peter Gay, Copyright @ 1966 by W.W. Norton & Company, Inc.
 Underlying Themes in the Witchcraft of Seventeenth-Century New England, John Demos, The American Historical Review Vol. 75, No. 5 (Jun. 1970), pp. 1311-1326 https://www.jstor.org/stable/1844480?seq=1#page_scan_tab_contents
 The Salem Witch Trials Victims: Who Were They? Rebecca Beatrice Brooks, August 19, 2015. https://historyofmassachusetts.org/salem-witch-trials-victims/
 Projection in Relationships: Stop it from ruining your connection, Monika Hoyt, Mar 12, 2016.https://www.monikahoyt.com/projection-in-relationships/
 Is Projection the Most Powerful Defense Mechanism? Grant Hilary Brenner MD, FAPA, Posted Sep 09, 2018. https://www.psychologytoday.com/us/blog/experimentations/201809/is-projection-the-most-powerful-defense-mechanism