Sensation and Perception 1

structured light

According to Alhazan's pointillistic theory of intromission, copies are images carried in the form of _____ ______.

da vinci

Advanced Alhazan's theory by recognizing the retina as the sensitive part of the eye. Modeled the eye as a camera obscura (sometimes called a pinhole camera), in which rays of light enter a point on a box and hit the back of the box to make an accurate 2D representation (picture) at the back of the box.

bipolar, ganglion

After light is absorbed by the receptors, the _____ cells transfer the signal back to the _____, and then the signal is sent to the brain.

compound eyes

eyes (of insects, e.g.) that have multiple tubes called ommatidia that keep each ray of light separate, and each receptor has its own lens. Very low-resolution.

Ontology

the branch of metaphysics dealing with the nature of being; theories about what exists

Fovea

the central focal point in the retina, around which the eye's cones cluster. Highest point of acuity. Peripheral vision goes to everything around the fovea.

trichromacy

the condition of possessing three independent channels for conveying color information, derived from the three different cone types

depth of field

the distance between the nearest and the furthest objects that give an image judged to be in focus in a camera. (range of distances over which the image is focused). A smaller pupil means a smaller depth of field.

monism

the doctrine that reality is ultimately made up of only one essence

dualism

the doctrine that reality is ultimately made up of two essences (physical and spiritual)

visual form agnosia

the inability to recognize objects by sight

Chambered eyes

the kind of eyes we (humans) have, in which the eye is filled with a jelly-like fluid, and there is only one lens through which all rays of light enter.

threshold

the level of stimulation required to trigger a neural impulse

sensation and perception

the means by which we gain knowledge about what is in the world around us (how information gets "from the world into the head").

difference threshold

the minimum difference between two stimuli required for detection

cup eyes

when there is a depression in the eyespot to allow for the perception of the direction that light is coming from

additive color mixing

when you take two separate pieces of light and put them together to get a new, brighter color (all added together makes white)

subtractive color mixing

when you take two separate pigments and add them together to get a new, darker color (added all together makes black). This occurs because you are reducing the amount of light that gets reflected.

Descartes

(1596-1650) French philosopher who tried to explain mind-body dualism; "The mind is a ghost in the machine." Noticed that his dissections of the human body looked like automatons (with wiring).

empiricism

(Aristotle's) epistemological theory that you are born a blank slate (with no knowledge) and you LEARN through direct OBSERVATION.

mind-body dualism

(Descartes's) philosophical viewpoint that mind and body are separate entities that do not interact. The body is just the machine, while the brain is what houses the psyche/soul/sensation. This theory launched modern medicine because people had been afraid that the body was the home of the soul, and therefore did not want to mess with it.

nativism

(plato's) epistemological theory that knowledge is inherited; you don't LEARN anything, you just KNOW things.

Destructive Mapping

- The proximal stimulus is an impoverished version of the distal stimulus - Thus sensation is an inadequate support for perception and there must be some mental entity to fill in the gaps. (enrichment) - Da Vinci and Kepler both noted this concept.

sweet (energy), salty (necessary mineral), sour (decay), bitter (poison), umami (nutrition/protein)

5 basic tastes

Hermann Grid

A geometrical display that results in the illusion of dark areas at the intersection of two white "corridors." This perception can be explained by lateral inhibition.

Materialism

A monistic branch of ontology which says that the world is made up of material matter/mass (no such thing as spiritual)

method of limits

A psychophysical method in which the particular dimension of a stimulus, or the difference between two stimuli, is varied incrementally until the participant responds differently.

eyespot

A simple light-sensitive region in certain single-cellular and simple multi-cellular organisms (such as euglena, hatena, and worms). Act more like pain receptors than vision.

medium

A spiritual idea to Aristotle, today a term that we use to describe a vessel for conveying information

Forced Perspective

A system of constructing and arranging buildings and objects on the set so that they diminish in size dramatically from foreground to background, which creates the illusion of depth. (Works because you have lost the third dimension in your vision.)

single-cell recording technique

A technique in which researchers study the characteristics of an animal's brain and nervous system by inserting an electrode next to a single neuron. (Ganglion cells to study the retina)

Pointillistic (theory of emanation)

Alkindi's theory that the emanation is built up of separate elements - ("pencils" or "rays"). These beams bounce off in little bits and come back to build the copy of the object. (The perceiver receives what is called a "mosaic of points"--like pixels that make up a full image.)

animal, medium, object

Around 350 BC, Aristotle figured that perception involves what three things?

kepler

Astronomer who provided an understanding of how a lens would work to focus the light that enters the eye. Also solved the problem of how so many different beams can enter the eye at once and not get jumbled up

Refraction

Fish don't need their corneas to do ______ because the water does that for them. Rather, they have massive hanging lenses.

brighter

Greater amplitude means we perceive the light as being _______.

spatial layout

Because light travels through transparent media in straight lines, it preserves _____ _____.

George Berkeley

Guy who said that "The only reality is in the mind" Nothing exists if it is not perceived. Physical qualities projected on environment. Ideas are the only things we experience directly and are therefore the only things we can be sure of.

recognition

Can happen simultaneously to perception, or can come before or after. It is the step in which we are able to give a name to/consciously understand that which we perceive.

muller

Guy who thought that perception is of states of nerves, not of things in the world. Nerve impulses come between awareness and the world.

preferential looking

a research technique that involves giving an infant a choice of what object to look at (used for grating acuity, e.g.)

chemicals (Each receptor only responds to one chemical.)

Different ______ on our tongue cause different neurons to fire, resulting in our perception of taste.

Metamers

Different mixtures of wavelengths that look identical. More generally, any pair of stimuli that are perceived as identical in spite of physical differences.

Molyneux's Premise

Distance is a line presented to the eye with its end towards us, which must therefore be a point, thus distance is invisible. In other words, the point is the same regardless of how far away it originates. The third dimension is lost on the 2D retina.

Islamic (middle eastern)

During the Dark Ages, _______ thinkers such as Alkindi and Alhazan did all of the thinking and recording of information.

fundamental problem of perception

How does information cross the gap between the object in the world and the animal? (The answer must not postulate action at a distance)

colorblind

If you only have a single receptor pigment (or if you only had rods), then you are _____.

cues

In rationalism, stimuli that acquire meaning through association (Ex: Bell to Pavlov's dog). Distance is partly learned by these. You measure angles and "learn" distance. So is depth perception.

Alhazan

In the 11th Century, the Arab mathematician and scholar, _____, proposed that vision is based on light entering the eye rather than light coming from within the eye. The first to treat the eye as an optical instrument that can sense light energy, rather than spiritual energy. Also the first to nail down pointillistic intromission.

hyeropia (farsightedness)

Inability to see close-up objects clearly, caused by an overly convex lens and fixed with a secondary concave lens.

refracted, focused

Light can be _____ (bent), which allows it to be ______ by a lens.

ganglion, bipolar, receptors

Light enters through the ______ cells, passes through the _____ cells, and then goes to the (photo)______.

absorbed, reflected

Light is selectively _____ and ______, which is how our perception of the color and brightness of an object is created.

prospective control

Light is useful for _____ _____ because it reaches the eye almost instantaneously, so that we can see an object before we reach it.

radiant light

Light that comes directly from the source (sun, e.g.) and contains raw data about the world (causes different colors, e.g.)

red

Long cones code for the color ______.

redder, bluer

Longer wavelength means we perceive the light as being _______. Shorter wavelength means we perceive the light as being _______.

green

Medium cones code for the color _____.

Alkindi

Middle Eastern thinker who was responsible for the Pointillistic theory of emanation.

irvin rock

Modern philosopher guy who said: Our perception of the world is a construction of it. We assume that the "real world" exists without perception, but...

dualistic, monistic

Most theories of perception follow a _____ epistemology, even if they follow a ______ ontology. (Ex: If you created a robot that could "see" (had cameras that entered information into its programming computer), you would know that what it "sees" is only two-dimensional information. You have to add programming that allows it to map a three-dimensional representation in order to have it not run into objects. You don't have to think that the computer is a "soul" or whatever (monistic ontology), in order to know that the computer programming is what is guiding the robot, not the robot's "body".)

Chevreul illusion

Occurs when areas of different lightness are positioned adjacent to one another to create a border. The illusion is the perception of a light band on the light side of the border and a dark band on the dark side of the border, even though these bands do not exist in the intensity distribution.

olfactory

Odor molecules enter the nasal passage to reach receptor cells in the _____ membrane, which then send the smell to the _____ bulb and _____ nerve, so that the scent can be coded to the brain.

red

Our eyes are optimized to distinguish ____ from green because it helps us find food.

tone

Our hearing receptors are different for each _____.

purple

The color ______ we see only exists in our head. We don't see the part of the spectrum that actually is that color.

color deficiency

People with this condition (sometimes incorrectly called color blindness) see fewer colors than people with normal color vision and need to mix fewer wavelengths to match any other wavelength in the spectrum. This is because they only have two receptor pigments instead of three, so their codes are messed up.

relative, ratios, information

Perception is ______. It is of _____ which provide _____. (It is never absolute but always a comparison.)

yellow blue

S and M cones are coded on the x chromasome, so ____-____ color blindness is by far the more common type (especially in males)

sensory coding

Sensory receptors translate the physical properties of stimuli into patterns of neural impulses

blue

Short cones code for the color _____.

more

Short wavelengths (blue) are refracted _____ than long wavelengths (red)

neural convergence

Synapsing of a number of neurons onto one neuron (occurs in the bipolar cells; 120 rods --> 1 ganglion cell and 60 cones --> 1 ganglion cell)

lens

The amount of refraction caused by a given _____ shape is constant.

Lateral Inhibition

The enhancement of contrast at the edge of an object is the result of ______ ______.

oblique effect

The finding that vertical and horizontal orientations can be perceived more easily than other (slanted) orientations.

dark adaptation curve

The function that traces the time course of the increase in visual sensitivity that occurs during dark adaptation. (When you enter a dark room and your eyes adjust, that is your threshold for seeing light becoming smaller as you stay in the dark; threshold becomes smaller.)

copy

The fundamental assumption of most modern psychologists is: In order to perceive something, you must get a _____ of it into your head. (These ______s mediate our contact with the world; what actually resides in your head is just a representation.)

cribriform plate

The horizontal plate of the ethmoid bone separating the cranial cavity from the nasal cavity. Point of possible damage, which can affect your sense of smell if harmed.

ambient light

The light that bounces off an object and enters our eyes to give us the information and guide our perception about and of the object.

classical psychophysical methods

The methods of limits, adjustment, and constant stimuli, described by Fechner, that are used for measuring thresholds.

lateral inhibition

The pattern of interaction among neurons in the visual system in which activity in one neuron inhibits adjacent neurons' responses. (When you find the area that triggers a response in a nervous cell, moving laterally will inhibit/"turn off" the response of that cell.)

proximal stimulus

The perceived object; the copy

rod-cone break

The point on the dark adaptation curve at which vision shifts from cone vision to rod vision (at about 10 minutes in darkness)

dark adaptation

The process in which the eyes become more sensitive to light in low illumination. (Example of an adaptation that is actually an increase in sensitivity)

Muller's theory of specific nerve energies

Theory that the quality arising from a sensation depends on what nerves are stimulated. (Ex: If there is a "cold" stimulus, your nerves create for you the sensation of "coldness".)

ganglion

The static you see in complete darkness is because the receptive fields of ____ cells flash every once in a while in random patterns just to stay active.

Intromission

The theory where sight occurs by light entering the eyes to sense the world. Aristotle speculated about such a theory in the Classical era in Greece (he thought it was spiritual energy), Alhazen in 10th C in Egypt worked out rays geometrically bounce of objects and into the eye, and contemporary theory further develops this school of thought.

enrichment

The thing that must be added to sensation in order to form perception; when a mental entity (brain/mind) adds order to the effects of the senses to form a representation/copy. (How we make up for the effects of destructive mapping)

red, green, blue

The three pure colors we have receptors for (primary colors of light)

emanation

Theory that an inner fire (internal spiritual energy) sends out rays through the eyes that bring back information about the world

Newton

This guy's color experiments showed that individual colors can be isolated using a prism. A second prism did not split the color any further, so he was able to identify pure colors. (He identified 7, but it's really a spectrum.)

transformations, representations

Vision involves a series of _______ which then lead to a series of ________.

ambient, radiant

Visual systems sample _____ light and avoid _____ light.

red

We cannot see the color ____ at all at night. (It appears black because of our rods' inability to perceive that high a wavelength.)

echolocation (The bats are sending out sound waves to bounce off other objects to come back to them and provide information.)

What is an example of emanation that is actually real and verified?

prospective control

What is the fundamental purpose of perception?

Endosymbiosis

When the Hatena divide and one of them devours another creature, leaving it undigested to become part of its body so that it can have the eyespot and chloroplasts that the other half stole in the division

principle of univariance

With regard to cones, the principle that absorption of a photon of light results in the same response regardless of the wavelength of the light

green red

___-___ color blindness is extremely rare.

structured

_______ light comprises the ambient optic array. It is the light that carries information and allows for visual transformation.

anomalous trichromacy

a condition characterized by having three cone photopigments that respond to slightly different wavelengths than normal. May be able to see various shades of green as being very different.

Dichromacy

a condition in which a person has only two types of cones, instead of the normal three; in all such cases, the person has a limited form of color vision but cannot discriminate as many colors as a person with all three cone types

prism adaptation

adaptation to the inaccurate visual feedback obtained when looking through a wedge prism; reveals a mechanism that helps us compensate for inaccurate movements. (Example of calibration adaptation)

calibration

adjusting our perception based on feedback

lightness contrast

an effect in which the intensity of large background regions can modify the lightness of smaller enclosed areas (same physical intensity produces different perceived lightness)

distal stimulus

an object or event in the outside world (the real object, not the copy)

bottom-up processing

analysis that begins with the sensory receptors and works up to the brain's integration of sensory information

knowledge

any information that the perceiver brings to a situation (for use in enrichment)

falciform process

big blob of black pigment on the back of fish eyes absorbs the light.

john locke

british empiricist who came up with primary and secondary qualities

Adaptation

change in sensitivity over time. (most often involves a decrease in sensitivity or a calibration; like when you get used to wearing a watch all the time)

secondary qualities

characteristics such as color and odor that only exist in our perception of the object

photopigments

chemicals in photoreceptors (rods and cones) that respond to light and assist in converting light into neural activity

intensity

coded as the frequency of nerve firing

quality

coded in terms of which nerves are firing

Transduction

conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.

astigmatism

defective curvature of the cornea or lens of the eye. Cornea is myopic in one direction and hyperopic in the other.

light

electromagnetic energy that varies in amplitude and wavelength. (only involves the very narrow band of electromagnetic energy used for vision and photosynthesis)

rationalism

epistemological theory that knowledge comes through REASON. You aren't born with information, but you also don't have to directly observe something in order to know it. You use logic to learn/create knowledge yourself.

principle of representation

everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and on activity in the person's nervous system

Myopia (nearsightedness)

inability to see distant objects clearly, caused by an overly concave lens and fixed with a secondary convex lens.

top-down processing

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

plato

introducer of mind-matter dualism

prospective control

making what we want to happen in our future happen using sensory information to make decisions; the fundamental purpose of perception

emmetropia

normal vision

neural processing

operations that transform electrical signals within a network of neurons or that transform the response of individual neurons

Pointillism

pencils or rays of light create a retinal mosaic

color circle (color wheel)

predicts the results of mixing colors and illustrates the cyclical continuum of colors.

mental entity

required to reconstruct/enrich the representations. (To Alkindi and Alhazan, this was spiritual, but it is true that we have visual receptors in our brain that interpret visual stimuli.)

cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.

rods

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond

absolute threshold

smallest stimulus level that can be detected

flavor

smell + taste = _______

principle of transformation

stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception.

crossover point

the point at which a person changes from detecting to not detecting a stimulus or vice versa

blind spot

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

sensory transduction

the process by which sensory stimuli transformed into energy in the nervous system

accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina (change the amount of refraction)

Cue Theory

the rationalist theory that we learn the connection between cues and depth through experience, then depth becomes automatic

grating acuity

the smallest width of lines that subjects can detect (was used to discover the oblique effect.)

Photoreceptors

the things that absorb light (rods and cones)

ambient optic array

the visual information contained in all of the reflected light (of different frequencies and wavelengths) that surrounds a viewer at any given point in time

scatter

the way light is absorbed and reflected in different degrees across the surface of an object to allow us to perceive properties like texture.

Epistemology

theory of knowledge/how things can be known

primary qualities

things that exist in the world without the necessity of a perceiver

lightness constancy

we perceive an object as having a constant lightness even while its illumination varies (different physical intensities produce the same perceived lightness)