← PSY 1: Introduction to Psychology

Unit 8: Consciousness, Attention, and Sleep

Why attention is a spotlight and not a floodlight, what that costs you, and what the sleeping brain is actually doing all night.

5 topics · 15 questions

Each topic is a path, not a menu: work down it in order and every question builds on the one above. Click any of them to watch the answer draw itself.

Selective Attention

  1. How it worksHow does selective attention filter incoming sound so only one stream gets fully processed at a time?
  2. Going furtherWhat happens to your ability to follow a conversation when you try to attend to two people talking at once?
  3. Common mistakeWhy isn't ignored information at a party actually unprocessed by the brain, given that your name still breaks through?
Your turn1 of 2
At a loud party, someone follows one conversation clearly while dozens of other conversations happen simultaneously all around them. A student assumes the brain must somehow physically block sound waves from every other conversation from reaching the ears at all. How does selective attention actually filter incoming sound so only one stream gets fully processed?

Inattentional Blindness and Change Blindness

  1. How it worksHow does a task that demands focused attention make an unexpected object in plain sight invisible?
  2. How it worksHow does change blindness let a large part of a scene change during a brief interruption without anyone noticing?
  3. Common mistakeWhy isn't failing to notice a big visual change proof that a person wasn't looking directly at it?
Your turn1 of 2
People asked to count basketball passes in a video routinely fail to notice a person in a gorilla suit walking directly through the middle of the scene, in plain sight the whole time. A student assumes anything appearing in plain sight, with eyes open and pointed right at it, must automatically be consciously seen. How does a demanding task make an unexpected object like this invisible?

The Stages of Sleep

  1. How it worksHow do EEG patterns change across light sleep, deep slow-wave sleep, and REM sleep?
  2. Worked exampleFind how many full 90-minute sleep cycles a person completes during 7.5 hours of sleep.
  3. Going furtherWhat happens to the balance of deep sleep and REM sleep across the hours of a single night?
Your turn1 of 2
Find how many full 90-minute sleep cycles a person completes during 7.63 hours of sleep.

REM Sleep and Dreaming

  1. How it worksHow does REM sleep's muscle paralysis stop a dreaming brain from acting out what it imagines?
  2. Common mistakeWhy isn't dreaming something that only happens during REM sleep?
  3. Going furtherWhat happens to REM sleep, and to mood, in someone who is repeatedly woken up right as they enter it?
Your turn1 of 2
During REM sleep, the body's major muscles go nearly paralyzed at the exact stage when the most vivid, story-like dreams occur. A student assumes this paralysis and the vivid dreaming happening at the same time must be an unrelated coincidence. How does REM sleep's muscle paralysis actually stop a dreaming brain from acting out what it imagines?

The Circadian Clock

  1. How it worksHow does the suprachiasmatic nucleus use light hitting the retina to keep the body's internal clock synced to 24 hours?
  2. Worked exampleFind roughly how many days it takes to adjust to a 6 hour time zone shift at about 1 hour of adjustment per day.
  3. Common mistakeWhy doesn't simply feeling tired at the new local bedtime mean your circadian clock has already reset?
Your turn1 of 2
Find roughly how many days it takes to adjust to a 8 hour time zone shift at about 1 hour of adjustment per day.