COMPLETED Sensation and Perception Unit 1

Top-down processing

Starts in the brain to influence how we interpret sensory data. Processing based on knowledge and the analysis of high-level information.

Bottom-up processing

Taking in sensory data without relying on prior knowledge. Processing based on the stimuli reaching the receptors.

Sensation

Lower-order processing of environmental energy mainly occurring at the cellular receptor level. Often identified with elementary processes that occur at the beginning of a sensory system.

Perception

Higher-order neural processing involving the interpretation of sensation. A conscious sensory experience.

What is an example of sensation?

The first process of rods and cones detecting light in the eye

What is an example of perception?

Visual information leaving the eye and going to the brain

Perception is highly influenced by ____ and _____

memory, environmental context

What is the dot example when it comes to differentiating sensation and perception?

One dot leans more towards sensation, multiple dots creating the shape of a house is leaning more towards perception.

What does the perceptual process start and end with?

Starts with environmental stimulus and ends with action.

What is step 1/7 of the perceptual process?

Raw energy from the distal stimulus

What is step 2/7 of the perceptual process?

Distal stimulus is focused so that it can be received by sensory receptors. The representation of the stimulus on the receptors is called the proximal stimulus.

What is the principle of transformation?

Stimuli and responses created by stimuli are transformed between the distal stimulus and perception. Environmental stimuluses and the responses they create are transformed from as they travel from the outside world into the brain as a conscious perception.

What is the principle of representation?

Everything a person perceives is based on a representation of the stimuli that is formed on the receptors and the resulting activity in the person’s nervous system. Not direct contact with stimuli.

What is step 3/7 of the perceptual process?

Cellular receptors convert raw energy. Every sense has cells specialized to respond to its energy type.

Transduction

transformation of environmental energy to electrical energy

What is step 4/7 of the perceptual process?

Neural processing. Energy is transmitted to and within the brain via interconnected neural networks.

What is step 5/7 of the perceptual process?

Perception. You’re aware of the stimulus.

What is step 6/7 of the perceptual process?

Recognition. You recognize what it is rather than just being aware.

What is step 7/7 of the perceptual process?

Action.

What type of processing is sensation?

Bottom-up processing

What type of processing is perception?

Top-down

Is step 1 of the perceptual process perception or sensation?

sensation

Is step 2 of the perceptual process perception or sensation?

sensation

Is step 3 of the perceptual process perception or sensation?

sensation

Is step 4 of the perceptual process perception or sensation?

Both

Is step 5 of the perceptual process perception or sensation?

Perception

Is step 6 of the perceptual process perception or sensation?

Perception

Is step 7 of the perceptual process perception or sensation?

Perception

Distal stimulus

The thing “out there” in the environment

Proximal stimulus

The representation of the distal stimulus on the receptors

Sensory receptors

Cells specialized to respond to specific types of environmental energy

What is an example of transduction?

Running fingers over tree bark. The stimulation of pressure receptors in our fingers would cause these receptors to produce electrical signals representing the texture of bark.

What is knowledge?

Any information that the perceiver brings to a situation

Stimulus-perception relationship

The association between stimuli and behavioral responses

Grating acuity

The smallest width of lines that subjects can detect

Method of Limits

Experimenter presents stimuli in either ascending or descending order

What is the goal of the method of limits

To determine the upper and lower limits of the sensory system

What is the absolute threshold?

The smallest detectable stimulus level

What is the difference threshold?

The smallest detectable difference between two stimuli

What is the Weber Law?

K = ΔS / S

Imagine we determine the JND (just noticeable difference) for a 30 0z weight is 1 oz. What is the JND for a 60 oz weight?

2

What is the magnitude estimation?

The experimenter presents the standard stimulus and many similar stimuli while recording the behavioral response for each. The subject assigns numbers to a stimulus that are proportional to subjective degree. For example, I give you a stimulus with a value, like a 25 volt electric shock, and then say “that’s a value of 10”. ands then I give you another shock and you tell me what you think the value is.

What is the goal of magnitude estimation?

To determine the perceived magnitude curve for stimuli of that type

What is response compression

Increase in stimulus intensity is larder than your perception of it (perceived magnitude of it). (Ex: brightness)

What is response expansion?

Increase in stimulus intensity is smaller than increase in perceived magnitude. (Ex: Shocks)

What is signal detection theory?

Incorporates both sensory information and decisional processes into detecting signals

What is the goal of signal detection theory?

To model decisions. made when there is some level of uncertainty

What is a Hit in signal detection theory?

When you detect the stimulus when it was actually presented to you

What is a correct rejection in signal detection theory?

When you don’t detect the stimulus when it wasn’t presented to you

What is a miss in signal detection theory

When you fail to detect the stimulus when it is presented to you

What is a false alarm in signal detection theory?

When you detect the stimulus when it was not presented to you

What is the ROC curve?

A graphical depiction of the “hit” rate compared to the “false alarm” rate

How do you find hit rate?

hits / (hits + misses)

How do you find false alarm rates?

false alarms / (false alarms + rejections)

What is recognition testing?

Process of identifying a stimulus

What is reaction time?

The time between stimulus presentation and behavioral reaction

What is phenomenological report?

A verbal or written description of what you sense or perceive. A method of determining the relationship between stimuli and perception where the observer describes what they perceive.

Perceptual Process

A sequence leading to recognition of the stimulus and action with regard to the stimulus.

What is the proximal stimulus in vision?

The image on the retina

Neural processing

Collection of operations that transforms electrical signals within a network of neurons

Primary receiving area

Area that first takes in most of the signals initiated by a sense’s receptors.

What is the layer of the brain that contains the machinery for creating perception, language, memory, and thinking.

Cerebral cortex

What is the site of the cortical receiving area for vision?

Occipital lobe

What is the cortical receiving area for hearing and the termination point for visual processing’s ventral stream

Temporal lobe

What is the cortical receiving area for touch and the termination point of visual processing’s dorsal stream?

Parietal lobe

What is the area of the brain that plays a key role in perceptions involving the coordination of sensory information?

Frontal lobe

What is visual form agnosia?

The inability to recognize objects

Oblique effect

A phenomenon in visual processing where people see horizontal and vertical lines more accurately than diagonal or oblique lines.

Psychophysics

Category of quantitative methods for measuring relationships between stimulus properties and subject’s experiences

What is perceived magnitude?

The measure of stimuli, like light or sound, that indicated the degree of experience.

Electromagnetic spectrum

Continuum of energy that extends from very short wavelength gamma rays to long wavelength radio waves

What is the S-B relationship

Stimulus-behavior relationship. Changing the stimulus and seeing how that changes the behavior.

What is the S-P relationship?

Stimulus-physiology relationship. Changing the stimulus and seeing how that affects the physiological response. For example, there are larger neural responses in the brain for vertical and horizontal lines compared to diagonal lines (oblique effect)

What is the P-B relationship?

The physiology-behavior relationship. Changing the physiology and then seeing how that affects the behavior

Recognition Testing

Process of identifying a stimulus

Reaction Time

Time between stimulus presentation and behavioral reaction

Phenomenological report

Verbal/written description of what you sense or perceive

What is the P-P relationship?

The association between physiological and behavioral responses. For example, using fMRI to measure brain activity when comparing grating acuity.