Biological Bases of Behavior: Consciousness, Sleep, Sensation, and Vision

Flashcards covering Module 1.5 and Module 1.6: biological bases of consciousness, sleep stages, sleep disorders, dream theories, sensation, thresholds, and visual processing.

How does the modern psychological view of the unconscious differ from the historical view?

Historically, the unconscious was believed to be a hiding place for our most anxiety-provoking ideas and emotions, and uncovering them could lead to healing; modern psychologists view the unconscious track simply as information processing without awareness.

What is the psychological definition of consciousness?

Our subjective awareness of ourselves and our environment.

What is cognitive neuroscience?

The interdisciplinary study of the brain activity linked with cognition (thinking, knowing, remembering, and communicating).

What is dual processing?

The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

What is blindsight?

A condition in which a person can respond to a visual stimulus without consciously experiencing it.

How do parallel processing and sequential processing differ?

Parallel processing is processing multiple aspects of a stimulus or problem simultaneously, whereas sequential processing is processing one aspect of a stimulus or problem at a time (generally used to process new information or solve difficult problems).

How is sleep defined, and what distinguishes it from other forms of unconsciousness?

Sleep is a periodic, natural loss of consciousness—as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.

What is the circadian rhythm?

Our biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a $24\text{-hour}$ cycle.

What is REM sleep, and why is it referred to as paradoxical sleep?

Rapid eye movement sleep is a recurring sleep stage during which vivid dreams commonly occur; it is called paradoxical sleep because the muscles are relaxed (except for minor twitches) but other body systems are active.

What are the distinguishing features of insomnia, narcolepsy, and sleep apnea?

Insomnia involves recurring problems in falling or staying asleep; narcolepsy is characterized by uncontrollable sleep attacks where the person may lapse directly into REM sleep; and sleep apnea is characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.

What is REM sleep behavior disorder?

A sleep disorder in which normal REM paralysis does not occur; instead, twitching, talking, or even kicking or punching may occur, often acting out one's dream.

What is the role of the suprachiasmatic nucleus (SCN) in controlling the sleep-wake cycle?

It is a pair of cell clusters in the hypothalamus that controls circadian rhythm by adjusting melatonin production in response to light, modifying feelings of sleepiness.

What are hypnagogic sensations and hallucinations?

Hallucinations are false sensory experiences (such as seeing something in the absence of an external visual stimulus), while hypnagogic sensations are bizarre experiences (such as jerking or a feeling of falling or floating weightlessly) while transitioning to sleep.

How do alpha waves, beta waves, and delta waves differ?

Beta waves correspond to an alert, waking state; alpha waves are the relatively slow brain waves of a relaxed, awake state; and delta waves are the large, slow brain waves associated with deep Stage $3$ sleep.

What does NREM sleep encompass?

Non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep (Stages $1$, $2$, and $3$).

What is the definition of a dream?

A sequence of images, emotions, and thoughts passing through a sleeping person's mind.

What is REM rebound?

The tendency for REM sleep to increase following REM sleep deprivation.

What explanations do information processing, physiological function, and activation synthesis theories offer for dreaming?

Information processing suggests dreams help sort out the day's events and consolidate memories; physiological function posits regular brain stimulation from REM sleep develops and preserves neural pathways; activation synthesis states REM sleep triggers neural activity that the brain weaves into stories and visual memories.

How do sensation and perception differ?

Sensation is the process by which sensory receptors and the nervous system receive and represent stimulus energies from our environment, whereas perception is the process by which the brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.

What is the difference between bottom-up processing and top-down processing?

Bottom-up processing begins with sensory receptors and works up to the brain's integration of sensory information, while top-down processing is guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

What is transduction in sensation?

Conversion of one form of energy into another; in sensation, transforming physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret.

What is psychophysics?

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

What is an absolute threshold?

The minimum stimulus energy needed to detect a particular stimulus $50\%$ of the time.

What does signal detection theory predict?

A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise); it assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

What is sensory adaptation?

Diminished sensitivity as a consequence of constant stimulation.

What is the difference threshold, and how does it relate to the just noticeable difference (jnd)?

The minimum difference between two stimuli required for detection $50\%$ of the time; we experience the difference threshold as a just noticeable difference (jnd).

What does Weber's law state?

The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).

What is priming?

The activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.

How do wavelength and intensity determine the visual characteristics of light?

Wavelength (the distance from the peak of one wave to the peak of the next) determines hue (color names like blue, green), whereas intensity (determined by wave amplitude/height) influences perceived brightness.

What are the anatomical structures and functions of the cornea, pupil, and iris?

The cornea is the eye's clear, protective outer layer covering the pupil and iris; the pupil is the adjustable opening in the center of the eye through which light enters; and the iris is a ring of muscle tissue that forms the colored portion of the eye and controls the size of the pupil opening.

What are the functions of the lens and the retina in the eye?

The lens is the transparent structure behind the pupil that changes shape to help focus images on the retina, and the retina is the light-sensitive back inner surface of the eye containing receptor rods and cones plus layers of neurons that begin the processing of visual information.

What is accommodation in the visual system?

The process by which the eye's lens changes shape to focus images of near or far objects on the retina.

How do rods and cones differ in their functions and retinal locations?

Rods detect black, white, and gray, are sensitive to movement, and are necessary for peripheral and twilight vision; cones are concentrated near the center of the retina (fovea), function in daylight or well-lit conditions, detect fine detail, and give rise to color sensations.

What is the blind spot of the eye, and what causes it?

The point at which the optic nerve leaves the eye, creating a 'blind' spot because no receptor cells are located there.

What is the fovea?

The central focal point in the retina, around which the eye's cones cluster.

What are the utility and limitations of case studies in psychological research?

Case studies are a non-experimental method that shows what can happen and may offer ideas for further study, but their generalizability is limited.

What is the path of visual information through the retinal layers to the brain?

Light stimulates receptor rods and cones, which send neural signals to bipolar cells, then to ganglion cells (whose axons form the optic nerve), which transmit impulses to the brain.

What are feature detectors?

Nerve cells in the brain's visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement.

What does the opponent-process theory state about color vision?

The theory that opposing retinal processes (red-green, blue-yellow, white-black) enable color vision; for example, some cells are stimulated by green and inhibited by red, while others are stimulated by red and inhibited by green.

What is the Young-Helmholtz trichromatic (three-color) theory?

The theory that the retina contains three different types of color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.

What is a scientific hypothesis?

A falsifiable prediction that can be used to check a theory or produce practical applications of it.