Perception and consciousness COPY Flashcards
Perceptual organization:
Although a visual scene may contain a copious amount of information about many different features (e.g., color, shape, motion, contours, etc.) and these features are processed separately by distinct neural systems, we perceive (“see”) unified objects in the scene because our brains recombine these elements, binding them together.
• How these features are organized into objects is governed by gestalt principles and influenced by bottom-up and top-down processing.
Gestalt principles:
- Gestalt principles: This body of research emphasizes the point that how we organize the barrage of incoming sensory information is a central feature of perception.
- Visual information—i.e., a barrage of information about various visual features—tends to be organized (or “parsed”) according to the following principles:
Similarity: Similar-looking figures tend to be grouped together, e.g., by color and orientation.
Proximity: Figures that are closer together in space tend to be grouped together.
Continuity of subjective contours: We tend to group figures together to perceive contours (edges) that may not physically exist in a visual scene.
For example, all three of these principles are at work when we perceive a zebra standing behind a tree. Its hind legs and tail are visible on one side of the tree, and its front legs and head are visible on the other. Yet we recognize and perceive a single zebra because of the similarity and proximity of the two separate parts and because of our innate preference for continuity of contours.
Closure: We tend to fill in missing parts or gaps to create a whole.
Similarity:
Similarity: Similar-looking figures tend to be grouped together, e.g., by color and orientation.
Proximity:
Proximity: Figures that are closer together in space tend to be grouped together.
Continuity of subjective contours:
Continuity of subjective contours: We tend to group figures together to perceive contours (edges) that may not physically exist in a visual scene.
For example, all three of these principles are at work when we perceive a zebra standing behind a tree. Its hind legs and tail are visible on one side of the tree, and its front legs and head are visible on the other. Yet we recognize and perceive a single zebra because of the similarity and proximity of the two separate parts and because of our innate preference for continuity of contours.
Closure:
Closure: We tend to fill in missing parts or gaps to create a whole.
Closure: objects grouped together are seen as a whole. Mind fills in missing information. Ex. You fill in the triangle even though there is none.
Depth Perception
Monocular cues: need information from only one eye.
Interposition: one object in front of another; cues depth perception.
Motion parallax: When we are moving, we tend to perceive objects that are closer to us as moving faster.
Binocular cues: need information from both eyes.
part of depth perception 2
interposition and motion parallax
Interposition: one object in front of another; cues depth perception.
- added: Perception that one object is in front of another. An object that is in the front is closer.
- *Monocular cues can also give a sense of motion**
- Motion parallax- “relative motion” Things farther away move slower, closer moves faster.
Motion parallax: When we are moving, we tend to perceive objects that are closer to us as moving faster.
MONOCULAR CLUES*
Types of processing:
Types of processing: What we perceive is a product of two simultaneous processing streams.
Bottom-up processing is driven by sensory inputs; e.g., when reading a list of words, we recognize the shape of the letters that make up the words, and upon recognizing the letters C, A, and T, we perceive the word “cat” and imagine a furry animal with four legs and a tail.
Top-down processing is driven by our own internally generated ideas and expectations; e.g., when reading the same list of words, we might recognize words for animals slightly faster than other words if we have just spent some time in a pet store.
Bottom-up processing
Bottom-up processing is driven by sensory inputs; e.g., when reading a list of words, we recognize the shape of the letters that make up the words, and upon recognizing the letters C, A, and T, we perceive the word “cat” and imagine a furry animal with four legs and a tail.
Bottom up Processing: Begins with stimulus. Stimulus influences what we perceive (our perception).
o No preconceived cognitive constructs of the stimulus (never seen it before)
o Data driven. And the stimulus directs cognitive awareness of what you’re looking at (object)
o Inductive Reasoning. Always correct.
Top-down processing is
Top-down processing is driven by our own internally generated ideas and expectations; e.g., when reading the same list of words, we might recognize words for animals slightly faster than other words if we have just spent some time in a pet store.
Top-down Processing: uses background knowledge influences perception. Ex. Where’s waldo
o Theory driven. Perception influenced by our expectation
o Deductive Reasoning
o ex. creating a cube when it’s not there! Not always correct.
consciousness
Our constantly updated awareness of ourselves, our environments, and the relationship between the two; may enable executive control—the capacity to override well-learned habits and actively redirect our attention, thoughts, and actions to accomplish a goal.
Sleep 1
A state of consciousness characterized by low alertness.
In deep sleep, there is an absence of consciousness.
In dreaming sleep, consciousness is present (but altered) and alertness remains low.
In deep sleep…..
In deep sleep, there is an absence of consciousness
In dreaming sleep……..
In dreaming sleep, consciousness is present (but altered) and alertness remains low.
stages of sleep 1
Stages of sleep: can be characterized by measuring muscle tone and brain activity rhythms through an EEG (electroencephalogram).
Non-REM Stage 1: falling asleep; a mix of alpha (8–13 Hz) and theta (4–7 Hz) waves on EEG; normal muscle tone.
NREM Stage 2: light sleep, still easily awoken by stimulation; mostly theta waves on EEG with sleep spindles and K-complexes.
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
Non-REM Stage 1:
Non-REM Stage 1: falling asleep; a mix of alpha (8–13 Hz) and theta (4–7 Hz) waves on EEG; normal muscle tone.
high frequency, same frequency we are when awake
NREM Stage 2:
NREM Stage 2: light sleep, still easily awoken by stimulation; mostly theta waves on EEG with sleep spindles and K-complexes.
brain slowing down
NREM Stage 3:
NREM Stage 3: deeper sleep, hard to awaken; delta (<3.5 Hz) waves on EEG with high amplitude.
NREM Stage 4
NREM Stage 4: deepest sleep with strongest delta activity and highest amplitude.
MOST RESTORATIVE, most refreshing sleep, very active dreaming
there is something abotu rem sleep that we need, mystery what it is doing for our brain we do not actually know
Rapid eye-movement (REM) sleep
alpha (8–13 Hz) waves on EEG, similar to wakefulness, but difficult to arouse and absent muscle tone.
-REM initiated by acetylcholine, inhibited by serotonin.
- Dreaming tends to occur during REM sleep.
- Bouts of REM sleep occur every 90 minutes and last longer later in the night.
- If deprived of REM one night, will compensate with more REM the following night.
alpha waves highest frequency, associated with REM, brain waves get slower
and slower then get fast again high frquency again as go through rem sleep
then go through another cycle of nonrem where get slower and slower