attention and perception

Chapter 4：

----selective attention：when does selection occur?

Selective attention: the ability to focus on one message and ignore all others.

A.Dichotic listening: one message is presented to the left ear and

another message is presented to the right ear. Participants are

instructed to pay attention to on message and to ignore the other

on and to repeat the attended message out loud. This procedures is

call SHADOWING.

B.Ical characteristics of the messagethe unattended ear.

C.Cocktail party phenomenon: the ability to pay attention to one

message and ignore all other messages.

D.How is this selection achieved? Filter model of attention:

1)human as an information processor

2)sensory memory: holds all of th incoming info for a fraction of

a second and then transfer all of it to the next stage: filter:

identifies the attended message based on its physical

characteristics-----next stage: Detector: proceses information to

determine higher-level characteristics of the message such as

its meaning.-------short term memory receives the output of the

detector. Holds info for 10-15s and also transfers info into

long-term memory.

3)Early-selection model: filters based on physical characteristics.

●Treisman’s attenuation theory

A.Attenuator: analyzes the incoming message in terms of its physical

characteristics( high or low pitched), its language- how the message groups into syllables or words, and its meaning.

B.Leaky filter model: at least some of the unattended message gets

through the attenuator.

C.Dictionary unit: analyzed the message in the second stage. The

dictionary unit contains stored words, each of which have thresholds for being activated. A shreshold is the smallest signal strength that can barely be detected ( own name need low signal strength to activated

●Late- selection models: selection of stimuli for final processing

doesn’t occur until after the info has been analyzed for its meaning.

A.Ambiguous sentence: They are throwing stone to the bank ( other

ear cue “money” or “river”

B.P.110 graph: difference between early selection and late selection.

When choose which? Determined by the nature of task.

------how does task load affect selective attention

●High-load task: uses most or all of a pe rson’s resources and so leaves

no capacity to handle other tasks.

●Low-load task: use few resources, leaving some to handle other tasks.

●FLANKER-CAMPATIBILITY TASK participant is presented with

a central display that may contain a target, and a “flanker” distractor

stimulus off to the side. Participant need to detect the target in the central display as quick as possible, while ignoring the distractor stimulus.

a)A compatible distractor, same as the target, low-load condition

(only 1 protential target)

b)An incompatible distractor. Different from the target.

c)High-load:: target is still the square, but there are 5 additional

shapes. The difference between the compatible and incompatible RT is not significant. When load is high, the type of distractor does not affect RT

-----------Divided Attention: paying attention to more than one thing

●Divided attention: the distribution of attention to two or more tasks

can occur.

●Automatic processing: first drive and drive for the long time: a type

of processiong that occurs 1 without intention and 2 at a cost of only some of a person;s cognitive rescources.

●S TROOP EFFECT:the words interfere with the ability to name the

coors of the ink, is caused by people’s inability to avoid paying

attention to the meanings of the words, even though they are instructed to ignore them, it is highly automatic that it is difficult not to read them, use few resources, but enough to slow down the speed.

●Controlled processing; processing used in the varied mapping

condition. Task is difficult, not possible to be automatic.

Directing visual attention with the eyes:

●Saccades: rapid movements of the eyes from one place to another

●Fixations: short pauses on points of interest

●Eye tracker: device to study eye movement

●Stimulus salience: conspicuous and therefore attract attention

based on their stimulus properties.

●Saliency map: to determine thether observer’s fixations were

controlled by the stimulus saliency indicated by the map

●Scene schema: knowledge about what is contained in typical

(office schema, phone, computer on the desk)

●Inattentional blindness: stimulus that is not attended is not

perceived, even though a person might be looking directly at it

●Precueing: participants looked at a small square that was flanked

by two lights on each side, initially none of the lights were turned

on

●OBJECT-BASED ATTENTION:when attentionis directed to

one plce on an object, theenhancing effect of this attention spreads throughout the object.

●Location-based attention: move attention from one place to

another.

●Cue signal appears at the top or bottom of one of the rectangles to

indicate where the target will probably appear, target appears at one of the ends of rectangle, RT in b faster than in C because the enhancing effect of attention had spread within the rectangle on the right, so even though the cue was at A some enhancement occurred at B, as well. P126

●Spotlight model: location-based bvisual attention can be likened

to a spotlight that scans different locations

●For dynamic environments, object-based visual attention can

incolve a mechanism that locks onto objects and follows them as they more.

●Autism: a serious developmental disorder in which one of the

major symptoms is the withdrawal of contact from other people.

Do not mke eye contact. Hard to tell emotions.

●Visual neglect: an effect of brain damage called visual neglect

causes a person to pay attention to only half of their visual field.

●Spatial cueing; how curing attetiong affects RT to the cued area,

spotlight model of attention.

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Chapter 5:

●Modal model of memory (structural features):

a)Sensory memory: an initial stage that holds all incoming info

for seconds or fractions of a second.

b)Short-term memory: holds 5-7 items for about 15-30s

c)Long-term memory: hold a large amount of info for years.

●Control processes, active processes that can be controlled by the

person and may differ from one task to another: for example: REHEARSAL: -repeat over and over again.2) strategies that use to hlp make a stimukus more memorable.3) strategies of attention that help you selectively focus on other info you want tp remember

●Persistence of vision: retention of the perception of light in mind (烟

火尾巴)

●iconic memory:the brief sensory memory for visual stimuli ,

corresponds to the sensory memory stage of Atkinson an shiffrin’s model.

●Echoic memory: the persistence of sound

Short-term memory

●Proactive interference (PI) interference that occurs when info that

was learned previously interferes with learning new info. Capacity of STM

●Digit span: one measure of capacity : the number of digits a

person can remember. (+-7)

●Chunking: small units can be combined into larger meaningful

units. Is a collection of elements that are strongly associated with

one another but are weakly associated with elements in other

chunks.

How is information coded in short-term memory?

●Coding: the way info is presented.

●Physiological approach to coding determine how a stimulus is

represented by the firing of neurons

●Mental approach to coding: how a stimulus or an experience is

represented in the mind.

●Auditory coding: remembering the sound

●Visual coding: conjuring up an image in mind

●Semantic coding: coding in terms of meaning: release from proactive

interference: eliminate the PI that had build up before

Working memory:a mechanism that consists of a number of specialized components

●Baddeley’s experiment: remember number when read a text:---ST

process must consist of a number of components that can function separately.

●Working memory: a limited-capacity system for temporary storage

an manipulation of info for complex tasks such as comprehension, learning and reasoning

a)STM is a single component, whereas working memory consists of

a number of parts

b)STM is concerned mainly with holding information for a brief

period of time, whereas working memory is concerned with the manipulation of in that occurs during complex cognition.

c)Phonological loop( verbal and auditory info) ---central

executive(pulls info from long-term memory and coordinates the activity of the phonological loop and visuospatial sketch pad by focusing on specific parts of a task and switching attention from one part to another. Decide how to divide attention between different tasks)---visuospatial sketch pad ( visual and spatial info)

The phonological loop

●Phonological similarity effect: occurs when letters or words that

sound similar are confused.

●Word-length effect: occurs when memory for lists of words is better

for short words than for long words. ( short words leave more space in the PL for rehearsal)

articulatory suppression: occurs when a person is prevented from rehearsing items to be remembered by repeating an irrelevant sound.

Effect: a) reduces the memory span

b)it eliminates the WLE ( eliminating rehearsal by “the, the, the”

eliminates the advantage for short word)

c)it reduces the PSE for reading words ( info not able to transfer

from visuospatial to phonological loop because the PL is

already engaged by “ the the the”.

. False Memories - How and Why:

A. The Misinformation Effect - an unconscious adoption of later-learned information. We know that our experiences affect memory...experiences that occur before, during, and after a memory is formed. Thus, the misinformation effect occurs when information received after a memory has formed influences the way we remember the event.

1) How - it occurs when someone fails to record into memory certain details of an event (remember, we can't process and store ALL pieces of information from an event). Then, when they see or hear another person's account of what occurred, they include these new pieces of information

into their own memory. This finding has been demonstrated empirically many times.

2) Children may be especially susceptible to this since they have less sophisticated encoding ability which results in more memory fragments. These fragments leave holes or gaps that are then filled in by experiences (social influences).

studies of memories of abuse in children. There was a series of studies a few years ago in which young children of different ages were given physical exams and then questioned about the exams afterwards (the interviews occurred right after the exam, a short time later, and then a few more times across the next Year). The doctors were part of the experimental team and acted according to a script and so children were treated and touched in very controlled ways (plus the exams were video taped). The children were asked about where the doctors touched them, how the doctors touched them, etc...much like children are questioned by police and Psychologists when trying to determine whether sexual abuse has occurred. The results indicated that, despite NO fondling or sexual contact in any way (no genitalia were touched, etc.), many of the children stated that they had been touched in inappropriate places by the doctors. Many of the reports did not happen at first, but over time and with different questions, the children began to alter their stories slightly.

3) Eye-witness testimony - despite the importance we place on eye-witness testimony in our legal system, experts agree that it is, at best, very questionable and susceptible to influence and change.

Police are notorious for using leading questions to evoke the types of responses they want from witnesses. For example, if you were a witness to a robbery, a police officer might ask you, "what type of gun did the robber have" instead of asking you "did the robber have any type of weapon". In addition, the more you learn about a case (TV, newspapers, etc.) the more likely you are to incorporate the new information into your own memory of the event.

Some final misconceptions about repressed memories

1) wouldn't repressed or false memories be less vivid?

No - research has shown that false memories are often "recollected" with more clarity and certainty than real memories

2) Wouldn't it be different for a traumatic event?

NO - research has shown that memories of real traumatic events in childhood often fade over time.

BUT - if an event is VERY TRAUMATIC it is more likely to become problematic due to inability to stop thinking about it. People often dwell on a traumatic event, not forget it (PTSD).

3) Does this mean that Repression is all a myth?

Not necessarily. The research is not conclusive, but suggests that repressed memories may not be as common as people may believe today (it seems to have gotten very hip today).