Consciousness is your own awareness of your thoughts, memories, feelings, sensations, and environments. This awareness is subjective.
Your conscious experiences can change from one moment to the next, but your experience of it may seem smooth.

Consciousness: A Subjective Awareness

Changes in consciousness can result in changes in perception, thinking, and interpretations of the world.
<ul>
<li>Some different states of consciousness include dreams, hallucinations, hypnosis, meditation, sleep, and states induce by psychoactive drugs.</li>
<li>Altered levels of consciousness can occur and may be caused by medical or mental conditions that change awareness, e.g., coma, confusion, delirium, disorientation, lethargy, and stupor.</li>
</ul>

Types of Consciousness

Changes of consciousness may be a sign of medical conditions, for example, aneurysm, brain infection, brain tumor or injury, dementia, drug use, epilepsy, heart disease, heatstroke, low blood sugar, poisoning, or shock.
If you think you are experiencing changes in consciousness, talk to your doctor.

Changes in Consciousness

<ul>
<li>The French philosopher Rene Descartes theorized the idea that while the mind and body are separate, they do interact.</li>
<li>Structuralists used introspection to analyze and report conscious sensations, thoughts, and experiences of their own minds. It was very subjective but inspired further research.</li>
<li>American psychologist William James thought consciousness was unbroken and continuous despite the constant changes.</li>
<li>Psychoanalyst Sigmund Freud focused on understanding the importance of the unconscious and conscious mind.</li>
</ul>

History of Consciousness

The study of consciousness does not have a universally accepted operational definition. Modern researchers have proposed two significant theories of consciousness.
<ul>
<li>Integrated Information Theory: This approach focus on learning about the physical processes that underlie our conscious experiences. It tends to focus on whether something is conscious and to what degree it is conscious.</li>
<li>Global Workspace Theory: This theory suggests that we have a memory bank from which the brain draws information to form the experience of conscious awareness.</li>
</ul>

Finding A Universal Definition

<figure><img src="https://www.verywellmind.com/thmb/PRuoDCRdx294bs6f_uaOjSZOu3k=/500x350/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/young-woman-contemplating-waterfall-1094075398-85faea78e80748a2af1b2cd60583540d.jpg" srcset="https://www.verywellmind.com/thmb/kLUwwT0DKiRGLBTTlWjontyIKYE=/300x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/young-woman-contemplating-waterfall-1094075398-85faea78e80748a2af1b2cd60583540d.jpg 300w, https://www.verywellmind.com/thmb/tIlJGt7sUkmPzI9TacUb4fXFNH0=/417x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/young-woman-contemplating-waterfall-1094075398-85faea78e80748a2af1b2cd60583540d.jpg 417w, https://www.verywellmind.com/thmb/DaLJYRRCfksxltwCzuYP4hNvB48=/534x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/young-woman-contemplating-waterfall-1094075398-85faea78e80748a2af1b2cd60583540d.jpg 534w, https://www.verywellmind.com/thmb/O2YNK3v11mMlUQoTvxoTPf-36Pk=/768x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/young-woman-contemplating-waterfall-1094075398-85faea78e80748a2af1b2cd60583540d.jpg 768w" alt="Young woman contemplating waterfall" width="721" height="481"><figcaption dir="auto">swissmediavision / Getty Images</figcaption></figure>
Consciousness refers to your individual awareness of your unique thoughts, memories, feelings, sensations, and environments. Essentially, your consciousness is your awareness of yourself and the world around you. This awareness is subjective and unique to you. If you can describe something you are experiencing in words, then it is part of your consciousness.

Your conscious experiences are constantly shifting and changing. For example, in one moment you may be focused on reading this article. Your consciousness may then shift to the memory of a conversation you had earlier with a co-worker. Next, you might notice how uncomfortable your chair is, or maybe you are mentally planning dinner.
This ever-shifting stream of thoughts can change dramatically from one moment to the next, but your experience of it seems smooth and effortless.<h2 dir="ltr"> Types of Consciousness </h2>
There are a number of things that can cause changes or alterations in consciousness. Some of these occur naturally, while others are the result of things such as drugs or damage to the brain. Changes to consciousness can also result in changes in perception, thinking, understanding, and interpretations of the world.

Some different states of consciousness include:
<UL><LI>Dreams</LI><LI>Hallucinations</LI><LI>Meditation</LI><LI>Sleep</LI><LI>States induced by <a href="https://www.verywellmind.com/what-is-psychoactive-22500" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="2" dir="ltr">psychoactive drugs</a></LI></UL>
There are two normal states of awareness: consciousness and unconsciousness. Altered levels of consciousness can also occur, which may be caused by medical or mental conditions that impair or change awareness.&nbsp;

Altered types of consciousness include:
<UL><LI>Coma</LI><LI>Confusion</LI><LI>Delirium</LI><LI>Disorientation</LI><LI>Lethargy</LI><LI>Stupor</LI></UL>
Doctors and healthcare professionals may use different assessments to measure and assess levels of consciousness. Scores on these assessments may be used to guide diagnosis and treatment decisions.1﻿
<h2 dir="ltr"> Uses </h2>
Understanding different levels of consciousness can help healthcare professionals spot signs that someone might be experiencing a problem.
Changes in consciousness can sometimes be a sign of medical conditions or they may even be a sign of an immediate medical emergency.
For example, sudden changes in consciousness might be a sign of:
<UL><LI>Aneurysm</LI><LI>Brain infections</LI><LI>Brain tumor or injury</LI><LI>Dementia or Alzheimer's disease</LI><LI>Drug use</LI><LI>Epilepsy</LI><LI>Heart disease</LI><LI>Heatstroke</LI><LI>Lack of oxygen to the brain</LI><LI>Low blood sugar</LI><LI>Poisoning</LI><LI>Shock</LI><LI>Stroke</LI></UL><h3>
When to Seek Help</h3>If you thinking you are experiencing changes in consciousness, talk to your doctor. Sudden changes may be a sign of a medical emergency that requires immediate attention, such as a stroke or hemorrhage.&nbsp;Talking to your doctor right away can ensure that you get immediate treatment before problems get worse.<h2 dir="ltr"> History of Consciousness </h2>
For thousands of years, the study of human consciousness was largely the work of philosophers. The French philosopher Rene Descartes introduced the concept of mind-body dualism or the idea that while the mind and body are separate, they do interact.

Once psychology was established as a discipline separate from philosophy and biology, the study of the conscious experience became one of the first topics studied by early psychologists.

Structuralists used a process known as <a href="https://www.verywellmind.com/what-is-introspection-2795252" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1" dir="ltr">introspection</a> to analyze and report conscious sensations, thoughts, and experiences. Trained observers would carefully inspect the contents of their own minds. Obviously, this was a very subjective process, but it helped inspire further research on the scientific study of consciousness.

The American psychologist <a href="https://www.verywellmind.com/william-james-biography-1842-1910-2795545" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="1" dir="ltr">William James</a> compared consciousness to a stream—unbroken and continuous despite constant shifts and changes. Psychoanalyst <a href="https://www.verywellmind.com/sigmund-freud-his-life-work-and-theories-2795860" data-component="link" data-source="inlineLink" data-type="internalLink" data-ordinal="2" dir="ltr">Sigmund Freud</a> focused on understanding the importance of the unconscious and conscious mind.

While the focus of much of the research in psychology shifted to purely observable behaviors during the first half of the 20th century, research on human consciousness has grown tremendously since the 1950s.
<h2 dir="ltr"> Theories of Consciousness </h2>
One of the problems with the study of consciousness is the lack of a universally accepted operational definition. Descartes proposed the idea of cogito ergo sum ("I think, therefore I am"), suggested that the very act of thinking demonstrates the reality of one’s existence and consciousness. While today, consciousness is generally defined as an awareness of yourself and the world, there are still debates about the different aspects of this awareness.

Research on consciousness has focused on understanding the neuroscience behind our conscious experiences. Scientists have even utilized brain-scanning technology to seek out specific neurons that might be linked to different conscious events. Modern researchers have proposed two major theories of consciousness: integrated information theory and global workspace theory.
<h3 dir="ltr"> Integrated Information Theory </h3>
This approach looks at consciousness by learning more about the physical processes that underlie our conscious experiences.2﻿ The theory attempts to create a measure of the integrated information that forms consciousness. The quality of an organism’s consciousness is represented by the level of integration.

This theory tends to focus on whether something is conscious and to what degree it is conscious.
<h3 dir="ltr"> Global Workspace Theory </h3>
This theory suggests that we have a memory bank from which the brain draws information to form the experience of conscious awareness.3﻿ While integrated information theory focuses more on identifying whether an organism is conscious, the global workspace theory offers a much broader approach to understanding how consciousness works.
<h2 dir="ltr"> A Word From Verywell </h2>
While consciousness has intrigued philosophers and scientists for thousands of years, experts clearly have a long way to go in our understanding of the concept. Researchers continue to explore the different bases of consciousness including the physical, social, cultural, and psychological influences that contribute to our conscious awareness.

Learn about how psychology defines consciousness, plus find out about aspects of consciousness including sleep, dreams, hypnosis, and meditation.

How Psychology Explains Consciousness

Consciousness: A Subjective Awareness

Types of Consciousness

Changes in Consciousness

History of Consciousness

Finding A Universal Definition

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