phototherapy.

Treatment of seasonal affective disorder with large doses of exposure to bright light.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

rapid eye movement (REM) sleep.

Periodic intervals of sleep during which the eyes move rapidly from side to side, and dreams occur, but the body is inactive.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

Rorschach inkblot test.

Projective test that uses irregular patterns of ink as its ambiguous stimuli.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003. Please note: the illustration is not an actual Rorschach inkblot, but is, I am assured, similar to the famous brand-name blots. What do you seeeee?

Saint Vitus’s Dance.

Instance of mass hysteria in which groups of people experience a simultaneous compulsion to dance and shout in the streets.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

sensorium.

Person’s general awareness of the surroundings, including time and place.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

smooth-pursuit eye movement.

Also called eye-tracking; the ability to follow moving targets visually. Deficits in this skill can be caused by a single gene whose location is known. This problem is associated with schizophrenia and thus may serve as a genetic marker for this disorder.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

somnabulism.

Repeated sleepwalking that occurs during NREM [non-REM] sleep and so is not the acting out of a dream. The person is difficult to waken and does not recall the experience.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

visuospatial skills.

Ability to see, recognize, orient within, and negotiate between objects in space.

—Essentials of Abnormal Psychology, third edition, V. Mark Durand & David H. Barlow, 2003.

chromatophores

“Cephalopods are among nature’s most colorful animals. Not even a chameleion . . . can compare with octopuses and squids when it comes to the variety and speed of color-changing wizardry. Cephalopods are unique in nature for in no other animals are color changes brought about by muscular control.

The strange, beautiful, and often startling color effects are the work of tiny pigment or color cells known as chromatophores which are located just beneath the skin. . . .

Among cephalopods the usual pigments are black, brown, red, yellow, and orange-red, and also many variations of those colors. No cephalod, however, has chromatophores with all these colors. Three pigments are the usual number in one animal.

The size of the chromatophores can be changed at will by the animals, as each cell is an elastic sac. Around it, radiating outward like spokes in a wheel, are microscopic strands of muscle. When these tiny muscles are relaxed there is no tension in the color sac and it remains small, so small that its pigment does not show. But when the muscles contract, they pull the chromatophore’s wall outward in all directions, making it much larger. Now its color pigment shows.

There are many thousands of these color bodies in the octopus’s skin and if they all happened to contract the creature would be a white or white-gray. When his chromatophores expand he takes on the color of their pigment and the change may take place as you watch. Many times you can actually see color ripple over his body.”

—Joseph J. Cook & William L. Wisner, The Phantom World of the Octopus and Squid, 1965.

The squid’s usual hue

“The squid’s usual hue is a light shade of pearly gray or gray-white, peppered with small dots of red or reddish brown. . . .

[T]he color-changing ability of many squids works in reverse to that of the octopus. Instead of going into a “fireworks” type of display, they tend to turn pale or lose color to the point of becoming practically invisible.”

—Joseph J. Cook & William L. Wisner, The Phantom World of the Octopus and Squid, 1965.