PSYCH 240 Quiz 4: Top-Down Processing and Attention

"Top"

Areas of the brain that are responsible for higher-level cognition

- Example: goal setting, decision-making, language, memory

"Bottom"

Lower level areas of brain that recieve input from sensation

Top-Down processing

Processing that originates in higher cognition and proceeds downwards towards sensation

- Driven by knowledge and expectations have an effect on perception and recognition

Bottom-up processing

Processing that originates in sensory areas and proceeds upward towards areas responsible for higher cognition

Expectation/Bias

Your own expectations or bias can affect the way you perceive something

- Ex: given a bunch of dots that are random until you find out it looks like a dog -> cannot unsee it... couldn't see it before but see it now

Signal detection theory

a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise).

- Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.

- Address biases or top-down expectations

Signal

Something in the environment you are trying to detect

Noise

Things in the environment other than the signal

Sensitivity

How easy/difficult it is to discriminate signal from noise

- Some people have better hearing

- Can have good/low sensitivity

Bias

Your tendency to say "yes" vs "no" determine by expectations or payoff

Payoff

a benefit received

- EX signal detection matrix

Signal detection Matrix

A matrix that measures hit, miss, correct rejection, and false alarms based upon payoffs.

Hit

There is a signal and you correctly detect it

Miss

There is a signal but you fail to detect it

Correct rejection

There is no signal but you say there was a signal

False alarm

There is no signal but you say there was a signal

Accuracy

% Hits + % Correct rejections

- depends on bias, sensitivity, proportions of trials

Payoff and Bias

The idea that if you were told that you get $10 for detecting a signal and -$1 for getting it wrong, you would often lower your threshold to not miss a signal since there's more money on the line.

- This can occur the other way where it's $1 for detecting a signal and -$10 for detecting a wrong signal, you're likely to increase your threshold to make sure you don't get a signal wrong.

- What we're doing is changing bias and this leads to different behaviors

Context effect

When perception of an object is affect by its context/environment

- Example: Subject contours, Ambiguous letters, Objects out of context

Word Superiority Effect

The idea that letters are easier to identify when they are part of a word than when they are seen in isolation or in a string of letters that do not form a word.

Interactive activation model

A connectionist model of visual pattern recognition that features both excitatory and inhibitory connections, and in which activation can flow from the top down (word level to letter level) as well as from the bottom up (features to letters, letters to words).

Dorsal stream

visual path in the parietal cortex that helps the motor system locate objects; the "where" path

Ventral Stream

a system of interconnected regions of visual cortex involved in the perception of form, beginning with the striate cortex and ending with the inferior temporal cortex, the "what" pathway

Focused attention

Multiple stimuli going to you and want to selectively attend to something, thus ignoring the other stimuli

Divided attention

Want to pay attention to multiple sources of info at the same time

Stroop task

Selectively ignore words and look at ink

- An example of focused attention/selective attention

- Tells us that we cannot completely shut down automatic processes, cannot help but do some of that processing

Cocktail party problem

the process of tracking one conversation in the face of the distraction of other conversations

- Studied with Dichotic Listening and Shadowing

Dichotic Listening and Shadowing

a subject having to repeat (shadowing) a certain message heard in one ear, and completely ignoring the other message in the other ear

Unconscious processing

processing of perception, memory, learning, thought, and language without being aware of it

- Example: put someone into a conversation in a party and while they are in that conversation, condition them to a target word such as "human" by shocking them (they don't know why). Afterwards ask them a series of words and see that whenever the word "human" is said they would sweat, which means they did process some information

- The sweat is called "Galvanic Skin Response"

Attenuate theory

Turning down the volume, not totally filtering out the info but lowering it's volume

Late filtering theory (Deutsch and Deutsch)

Doing full-blown process of the unintended message but you filter it out right before it reaches consciousness

Overt shifts of attention

Shifting attention from one place to another by moving the eyes

- Shift of attention that people can see from outside -> such as moving head to focus on a clock

Covert shifts of attention

Shifting attention from one place to another while keeping the eyes stationary

- Example: Paying attention to what's in front of you but secretly pay attention to something else, eyes are fixed but not our attention

Spotlight metaphor of attention

Spatial attention acts like a spotlight with variable focus (zoom lens) moving around the visual field. Information processing of stimuli falling in the spotlight is facilitated compared to stimuli falling outside of the spotlight.

Feature Integration Theory

the idea that focused attention is not required to detect the individual features that comprise a stimulus, but is required to bind those individual features together

- Feature search: automatic, fast, independent upon numbers of distractors

- Conjunction search: controlled, slow, effortful, depends on # of distractors

Visuospatial neglect

Can see fine but patient neglects one side of the object

Disengage Deficit

The reason patients neglect the left side of space is because their attention is stuck on the right side of space and cannot pull it away

Unbalanced compeition

Damage to one hemisphere causes other hemisphere to dominate

Driver Reading

selective attention, selective listening, filter theory, unattended processing, early selection, attenuation, late selection, feature integration theory, serial attention, convert mechnisms, attention and brain, residual processing, grouping, attentional affects, erps and fmri, left and right brain

Broadbent's filtering model

Two stages:

1. Physical properties that would be extracted for all incoming stimuli in a parallel manner.

2. Would contain more complex psychological properties that go beyond simple physical characteristics that were extracted

- Second stage have more of a limited capacity so there would be a filter between two stages that only allowed information with certain physical properties to enter the second stage.