Standard consciousness glossary

neuroscience · intermediate

Default Mode Network

Also called: DMN

A set of interconnected brain regions, including parts of the medial prefrontal and posterior cingulate cortex, that becomes more active when a person is not focused on the external world, such as during mind-wandering, self-reflection, or recalling memories. It was identified through neuroimaging studies noting consistent brain activity during supposed rest periods, and its activity typically decreases during externally focused, effortful tasks.

clinical-and-disorders · intro

Delirium

An acute, typically fluctuating disturbance of attention, awareness, and cognition that develops over a short period, often caused by an underlying medical illness, medication effect, or withdrawal. It is distinguished from dementia by its rapid onset and fluctuating course, though the two conditions can co-occur and delirium is more common in patients who already have an underlying dementia.

clinical-and-disorders · intro

Dementia

A general term for a progressive, typically irreversible decline in cognitive function, including memory, reasoning, and language, severe enough to interfere with daily functioning. Alzheimer's disease is the most common underlying cause, though dementia can also result from vascular disease, Lewy body pathology, and several other conditions.

sleep-and-altered-states · intermediate

Depersonalization

A dissociative experience characterised by a persistent or recurrent feeling of being detached from, or an outside observer of, one's own thoughts, feelings, or body, often described as feeling unreal or automated. It can occur transiently under extreme stress or fatigue, or persist as part of a diagnosable dissociative disorder.

sleep-and-altered-states · intermediate

Derealization

A dissociative experience characterised by a persistent or recurrent feeling that the external world is unreal, dreamlike, or distant, even though a person can usually still recognise, on some level, that this feeling does not reflect an objective change in reality. It frequently co-occurs with depersonalization.

clinical-and-disorders · intermediate

Disorders of Consciousness

An umbrella clinical term covering conditions of severely altered or diminished consciousness following brain injury, including coma, the vegetative state, and the minimally conscious state, distinguished from one another by the specific pattern of preserved wakefulness and awareness each involves. Accurately distinguishing between these states has real clinical stakes, since misdiagnosis affects treatment and end-of-life decisions.

sleep-and-altered-states · intermediate

Dissociation

A disruption in the normal integration of consciousness, memory, identity, or perception of the environment, ranging from mild, everyday experiences such as becoming absorbed in a task and losing track of time, to more severe clinical presentations involving disconnection from one's sense of self or surroundings. It can occur as a response to acute stress or trauma.

cognitive-science · intermediate

Divided Attention

The cognitive ability to process and respond to more than one task or source of information at the same time. Performance on divided-attention tasks generally degrades as the component tasks become more similar or more demanding, which is part of the evidence behind warnings against activities like using a phone while driving.

neuroscience · intro

Dopamine

A neurotransmitter involved in reward, motivation, movement, and reinforcement learning. Dopamine release is associated with the anticipation of reward as much as the reward itself, which is part of why it plays a central role in theories of addiction and habit formation. The loss of dopamine-producing neurons in a specific midbrain region is the primary cause of Parkinson's disease.

cognitive-science · intermediate

Dual-Process Theory

A framework proposing that human thinking operates through two distinct types of processes: a fast, automatic, intuitive mode and a slower, effortful, deliberate mode. It was popularised for a general audience by psychologist Daniel Kahneman as System 1 and System 2 thinking, and is used to explain patterns of cognitive bias that arise when fast, intuitive processing overrides more careful reasoning.

philosophy-of-mind · intro

Dualism

The view that mind and body, or mental and physical properties, are fundamentally distinct kinds of thing, neither reducible to the other. René Descartes' substance dualism, which held that mind and matter are two separate kinds of substance, is the most historically influential version, though it faces the longstanding challenge of explaining how two entirely distinct substances could causally interact.