Chapter 14 – Cognitive Functions

Question 1

Bundle of axons that connects the two hemispheres of the cerebral cortex

Answer 1

Corpus callosum

Question 2

Divisions of labour between the two brain hemispheres

Answer 2

Lateralization

Question 3

Describe the visual, auditory, taste, and smell connections to the hemispheres of the brain

Answer 3

The left hemisphere is connected to skin receptors and muscles mainly on the right side of the body, and the right hemisphere to the left side. Both hemispheres control the trunk muscles and facial muscles.

Visual: the right hemisphere sees only the left half of the world, and the left hemisphere sees the right half of the world.

Auditory: each hemisphere gets auditory information from both ears but slightly stronger information from the contralateral ear.

Taste and smell: both are uncrossed. Each hemisphere gets taste information from its own side of the tongue and smell information from the nostril on its own side

Question 4

Describe the areas of the cerebral cortex that exchange information between the left and right hemispheres

Answer 4

The corpus callosum, the anterior commissure, the hippocampal commissure, and a couple of other small commissures

Question 5

Describe the division of labour between the left and right hemispheres

Answer 5

In most humans, the left hemisphere specialized for language. The functions of the right hemisphere are more difficult to summarize, but is better at perceiving emotions and at comprehending spatial relationships

Question 6

Area of the world that an individual can see at any time

Answer 6

Visual field

Question 7

Light from the right half of the visual field strikes the ____ half of each retina, and light from the left visual field strikes the _____ half of each retina.

The left half of each retina connects to the _____ hemisphere, which therefore sees the right visual field. Similarly, the right half of each retina connects to the _____ hemisphere, which sees the left visual field.

Answer 7

Left; right; left; right;

Question 8

Area where the axons from each eye cross to the opposite side of the brain

Answer 8

Optic chiasm

Right visual field – left half of each retina – left hemisphere

Left visual field – right half of each retina – right hemisphere

Question 9

The left hemisphere of the brain is connected to the right eye in rabbits. In humans, the left hemisphere is connected to the left half of each retina. Explain the reason for this species difference.

Answer 9

In rabbits, the right eye is far to the side of the head and sees only the right visual field. In humans, the eyes point straight ahead and half of each eye sees the right visual field

Question 10

In humans, light from the right visual field strikes the ______ half of each retina, which sends its axons to the ______ hemisphere of the brain

Answer 10

Left; left

Question 11

A condition characterized by repeated episodes of excessive synchronized neural activity

Answer 11

Epilepsy

Question 12

People who have undergone surgery to the corpus callosum

Answer 12

Split-brain people

Question 13

Point in the brain where an epileptic seizure begins

Answer 13

Focus

Question 14

Describe various methods of treating epilepsy

Answer 14

Anti-epileptic drugs that block sodium flow across the membrane or enhance the effects of GABA.

Surgical removal of the focus, the point in the brain where the seizures begin.

Removing the focus is not an option if someone has several foci, and sometimes cutting the corpus callosum to prevent epileptic seizures from crossing from one hemisphere to the other is a possible treatment

Question 15

Describe how having the corpus callosum cut has affected the daily lives of people who had this operation and their ability to do conflicting tasks with their two hands.

Answer 15

They maintain their intellect and motivation, and they still walk without difficulty and use the two hands together on familiar tasks such as tying shoes. However, they struggle with any task that is not familiar to them.

Split-brain people have no trouble planning two actions at once, such as simultaneously moving your left hand one way and your right hand a different way.

Question 16

Describe the research by Roger Sperry where a split-brain person stared straight ahead as the experimenter flashed words or pictures on either side of the screen, too briefly for the person to move his or her eyes.

Answer 16

Information going to one hemisphere could not cross to the other, because of the damage to the corpus callosum. The person could. With the left-hand to what the right hemisphere saw and can point with the right-hand to what the left hemisphere saw. The person could talk about what the left hemisphere saw, but not what the right hemisphere saw, because in most people, the left hemisphere controls speech. The two halves of the brain had different information, and they could not communicate with each other

Question 17

Can a split-brain person name an object after feeling it with the right hand? With left hand? Explain.

Answer 17

A split-brain person can describe something after feeling it with the right hand but not with the left. The right-hand sends its information to the left hemisphere, which is dominant for language in most people. The left-hand sends its information to the right hemisphere, which cannot speak.

Question 18

Describe competition and cooperation between the split hemispheres of the brain

Answer 18

Conflicts are more common soon after surgery than later. The corpus callosum does not heal, but the brain learns to use the smaller connections between the left and right hemispheres. The left hemisphere somehow suppresses the right hemispheres interference and takes control in some situations.

Morphed pictures study: when he saw a picture in the right visual field (left hemisphere), he was more likely to say it was himself. When he saw it in the left visual field (right hemisphere), he usually thought it was the other person

Cooperation: when the left hemisphere guesses about what the right hemisphere saw, the right hemisphere, which knows the correct answer, makes the face frown, and the left hemisphere feeling the frown says that they meant the other answer

When a split brain person saw one group of words with the right visual field, and another group with a left visual field, the opposite hands could draw the different words but could not combine the words into one concept, such as hotdog or skyscraper

Question 19

Describe the functions of the right hemisphere

Answer 19

People with left-hemisphere brain damage are better at guessing whether a person is lying or telling the truth because they are better at reading gestures and facial expressions – the right hemisphere is better than the left at perceiving the emotions in peoples gestures and tone of voice, and if the left hemisphere is damaged and prevented from interfering with the right hemisphere, the right hemisphere is free to make reliable judgments.

Dominant for recognizing emotions in others, including both pleasant and unpleasant emotions.

Better than the left at comprehending spatial relationships

Question 20

What is a simple way to describe the difference in functions between the hemispheres?

Answer 20

As Robert Ornstein put it: the left hemisphere focuses more on details and the right hemisphere more on overall patterns

Question 21

Which hemisphere is dominant for the following in most people: speech, emotional inflection of speech, interpreting other people’s emotional expressions, spatial relationships, perceiving overall patterns?

Answer 21

The left hemisphere is dominant for speech. The right hemisphere is dominant for all the other items listed.

Question 22

Section of the temporal cortex that is larger in the left hemisphere

Answer 22

Plenum temporale

Question 23

Describe the maturation of the corpus callosum

Answer 23

Gradually grows and thickens as myelin increases around certain axons during childhood and adolescence.

Also matures by discarding many axons. The reason is that any two neurons connected by the corpus callosum need to have corresponding functions and during early embryonic development, the genes cannot specify exactly where those two neurons will be. Therefore, many connections are made across the corpus callosum, but only those axons that happen to connect very similar cells survive.

Because the connections take years to develop their mature adult pattern, certain behaviours of young children resemble those of split-brain adults:
When feeling fabrics with either one hand add two times or both hands at the same time, five-year-olds did equally well with one hand or with two at describing whether the materials felt the same or different. Three-year-olds may 90% more errors with two hands than with one. Interpretation – the corpus callosum matures sufficiently between ages three and five to facilitate the comparison of stimuli between the two hands.
When using the Etch-a-Sketch, adults and older children are slower to respond with two hands than with one, presumably because the message to one hand interferes with the message to the other hand. Children younger than six years respond just as fast with two hands as with one, again suggesting that they do not yet have a mature corpus callosum

Question 24

Describe what happens when a person develops without a corpus callosum

Answer 24

They are unlike people who have it cut in later life:

Whatever prevented formation of the corpus callosum undoubtedly affects brain development in other

The absence or near absence of the corpus callosum induces the remaining brain areas to develop differently

ways.
- perform more slowly or less accurately than average on tasks that require cooperation between the two hemispheres.
- perform reasonably well on many tasks were split brain people fail – verbally describe what they feel with either hand and what they see in either visual field, also feel objects with two hands and say whether they are the same or different.
How? Each hemisphere develops pathways connecting it to both sides of the body, enabling the left or speaking hemisphere to feel both the left and right hands. Also, the brains other commissures become larger than usual, including the anterior commissure. The extra development of these other commissures partly compensates for the lack of a corpus callosum

Question 25

A child born without the corpus callosum can name something felt with the left-hand, but an adult who suffered damage to the corpus callosum cannot. What are two likely explanations?

Answer 25

In children born without a corpus callosum, the left hemisphere develops more than The usual connections with the left-hand, and the anterior commissure and other commissures grow larger than usual

Question 26

Describe the relationship of handedness and language dominance to the anatomical differences between the hemispheres

Answer 26

For more than 95% of right-handed people, the left hemisphere is strongly dominant for speech.
Left-handers are more variable, most have left hemisphere dominance for speech, but some have right hemisphere dominance or a mixture of left and right.

Many left handers who have partial right hemisphere control of speech are also partly reversed for spatial perception, showing more than the usual amount of left hemisphere contribution. A few left-handers have right hemisphere dominance for both language and spatial perception

Hand preference and other asymmetries in brain and behavior: right-handers are more likely to choose a path or turn to the left, and left handers are more likely to turn to the right. This tendency can be found in most races, where the track is set up for turning to the left or counterclockwise. And in baseball, where players run the bases to the left, counterclockwise.

Question 27

Ability of language to produce new signals to represent new ideas

Answer 27

Productivity

Question 28

Describe the language abilities of common chimpanzees

Answer 28

After many unsuccessful attempts to teach chimpanzees to speak, researchers achieve better results by teaching them American sign language or other visual systems.

The chimpanzees seldom used symbols in new, original combinations. Their symbol used was short on productivity.

The chimpanzees used their symbols mainly to request, seldom to describe

Question 29

Describe the language abilities of Bonobos

Answer 29

Their social order resembles humans in several regards.

When researchers try to teach a Female mother to press symbols representing words, she made little progress, although, her infant son learned just by watching her, and when given a chance to use the symbol board, he quickly excelled.
Kanzi, The infant son and his sister developed language comprehension comparable to that of a typical 2 to 2 1/2 year-old child.

They understood more than they can produce

They use symbols to name and describe objects even when they are not requesting them

They request items that they do not see

They occasionally use the symbols to describe past events. Example, the infant son pressed buttons to say that his mother had bit him to explain the cut that he had received on his hand an hour earlier.

They frequently make original, creative requests, such as asking one person to chase another

Reasons for their more impressive skills:
May be because they have more language potential than common chimpanzees. May be because they began language training when young. And thirdly, perhaps they learn by observation and imitation better than the formal training methods of previous studies

Question 30

What are three likely explanations for why bonobos made more language progress than common chimpanzees?

Answer 30

Bonobos may be more predisposed to language than common chimpanzees. The bonobos started training at an earlier age. They learned by imitation instead of formal training techniques.

Question 31

Describe the language abilities of parrots

Answer 31

Spectacular results have been reported for Alex, and African gray parrot, who seemed to use sounds meaningfully.

Was kept in a stimulating environment and was taught by saying a word many times and offering rewards if Alex approximated the same sound. Generally used toys. Trainer would give Alyx what he asked for and not food.

In one test, Alex feud a tray of 12 objects and correctly answered 39 or 48 questions such as “what colour is the Key?”. Many of his incorrect answers were almost correct. He could also count.

Language was not always helpful: when untrained parrots were put on perches with a chain of large plastic links from the purge to an Almond on the bottom, the parrots untrained in language used their claws to pull up the chain until they reached the Allmond. Alex and another language-trained parrot repeatedly told the experimenter, “want nut” and gave up when they didn’t receive the almond

Question 32

What are the two categories that most theories about how humans evolved language fall into?

Answer 32

1. We evolved it as a byproduct of overall brain development

2. We evolved it as a specialization

Question 33

Describe the two problems with the hypothesis that language is a byproduct of overall brain development or intelligence.

Answer 33

1. It has been found that people with normal intelligence can have impaired language, thus, language requires more than just a large brain and overall intelligence.
   - in one family, 16 of 30 people over three generations showed severe language deficits despite normal intelligence in other regards due to a particular dominant gene which causes serious problems in pronunciation and many other aspects of language. Despite the language difficulties, these people behave normally and intelligently in most regards.
2. There are people with mental retardation but relatively spared language, which indicates that language is not simply a byproduct of overall intelligence.
   - people with Williams syndrome have mental retardation in most regards, but many speak grammatically and fluently. They are poor at tasks regarding numbers, visuospatial skills, and spatial perception. Many, however perform well, or at least close to normal in certain regards such as music, friendliness, and language.

Question 34

Condition in which the person has relatively good language abilities in spite of their impairments in other regards

Answer 34

Williams syndrome

Question 35

Describe the evidence for and against the development of language as a special module, or as a specialization

Answer 35

It has been proposed, by Noam Chomsky and others, that humans have a language acquisition device, a built-in mechanism for acquiring language. This is because most children develop language so quickly and easily that it seems they must have been biologically “prepared” for this learning. Also, deaf children quickly learn sign language.

There seems to be evidence of a genetic basis for the preparation in language, as evidenced by finding a mutation in the gene FOXP2 in the family mentioned previously. Altering this gene in mice cause changes in vocalizations and increased dendritic branching and synaptic plasticity in the basil ganglia.

Question 36

What evidence argues against the hypothesis that language evolution depended simply on the overall evolution of brain and intelligence?

Answer 36

Some people have normal brain size but very poor language. Also, some people are mentally retarded but nevertheless develop nearly normal language

Question 37

Describe tasks that people with Williams syndrome do poorly and those that they do well

Answer 37

Poor: numbers, visual-motor skills, and spatial perception. Relatively good: language, interpretation of facial expressions, social behaviors, some aspects of music.

Question 38

When researchers test whether people learn a second language best if they start young, the consistent result is that adults are better than children at memorizing the ________ of a second language, but children have a great advantage on learning the ________ and _______.

Answer 38

Vocabulary; pronunciation and grammar

Question 39

What is the strongest evidence in favour of a sensitive period for language learning?

Answer 39

Deaf children who are not exposed to sign language until later in life, and who did not learn spoken language either while they were young, do not become proficient at it.

Also, learning a second language in early childhood differs in many ways from learning it later.

Question 40

Language impairment

Answer 40

Aphasia

Question 41

Portion of the brain that is associated with language production

Answer 41

Broca’s area

Question 42

Brain damage that causes impaired language. Especially impairments in language production.

Answer 42

Broca’s aphasia or nonfluent aphasia

Usually caused by lesions in the left frontal cortex or left hemisphere, and usually due to stroke and sometimes results from diseases causing gradual atrophy.
Damage limited to Broca’s area produces only minor or brief language impairment. Serious deficits result from extensive damage that extends into other areas as well.

Question 43

Describe the symptoms of Broca’s aphasia

Answer 43

Difficulty in language production:
Slow and awkward with all forms of expression, including speaking, writing, and gesturing, as well as sign language for the deaf– So it relates to language, not just the vocal muscles.
Omit most pronouns, prepositions, conjunctions, auxiliary or helping verbs, quantifiers, and tense and number endings when speaking– These are known as the closed class of grammatical forms because a language rarely adds new prepositions, conjunction’s, and the like. In contrast, new nouns and verbs’s – the open class – enter a language frequently. People with Broca’s aphasia seldom use the clothed-class words.
May be because they have suffered damage to a grammar area in the brain, or, when speaking is a struggle, people leave out the weakest elements, such as the closed-class words

Problems in comprehending grammatical words and devices:
Have trouble understanding the same kinds of words, closed-class words, that they omit when speaking. They often misunderstand sentences with complex grammar.
Still, they have not totally lost their knowledge of grammar, and can generally recognize that something is wrong with a sentence, but cannot say how to improve it. Their comprehension resembles that of normal people who are distracted.

Question 44

What kinds of words are Broca’s patients least likely to use?

Answer 44

They have the greatest trouble with “closed-class” words that are meaningful only in the context of the sentence, such as prepositions, conjunctions, and helping verbs.

Question 45

What kinds of words do Broca’s patients have the most trouble understanding?

Answer 45

They have the most trouble understanding the same kind of words they have trouble producing – the closed-class words

Question 46

Portion of the brain located near the auditory cortex, associated with language comprehension

Answer 46

Wernicke’s area

Question 47

Condition characterized by poor language comprehension and impaired ability to remember the name of objects

Answer 47

Wernicke’s aphasia or fluent aphasia

Question 48

Describe the three typical characteristics of Wernicke’s aphasia:

Answer 48

1. Articulate speech – in contrast to people with Broca’s aphasia, those with Wernicke’s aphasia speak fluently, except when pausing to try to think of the name of something.
2. Difficulty finding the right word – anomia, difficulty recalling the names of objects. They make up names, substitute one name for another, and use roundabout expressions.
3. Poor language comprehension – have trouble understanding spoken and written speech, and sign language for deaf people.

Question 49

Difficulty recalling the names of objects

Answer 49

Anomia

Common in people with Wernicke’s aphasia

Question 50

Describe the speech production of people with Wernicke’s aphasia

Answer 50

They speak fluently and grammatically but omit most nouns and verbs and therefore make little sense

Question 51

Describe the speech comprehension of people with Wernicke’s aphasia

Answer 51

They understand little speech

Question 52

Describe the parallels in the brain between language and music

Answer 52

Both evoke strong emotions

Broca’s area is strongly activated during both

Trained musicians and music students tend to be better than average at learning a second language

In both language and music, we alter the timing and volume to add emphasis or to express emotion

English speakers average about 0.5 to 0.7 seconds between one stressed syllable and another in speech and prefer music with about 0.5 to 0.7 seconds between beats

Greek and Balkan languages have less regular rhythms than English, and much of the music written by speakers of those languages has irregularly spaced beats

English usually stresses the first syllable of a word or phrase, whereas French more often stresses the final syllable. Similarly, French composers more often than English composers make the final note of a phrase longer than the others

English vowels vary in duration more than French vowels do. English composers, on average, have more variation in note length from one note to the next

• The similarities and others suggest that we use the language areas of the brain when we compose music, and we prefer music that resembles our language in rhythms and tones. Also suggests that they arose together during evolutionary processes.

Question 53

In what way do musical compositions vary depending on the language spoken by the composer?

Answer 53

Musical compositions tend to follow the same rhythms that are common in the language spoken by the composer

Question 54

A specific impairment of reading in someone with adequate vision, adequate motivation, and adequate overall cognitive skills

Answer 54

Dyslexia

More common in boys than girls and has been linked to at least four genes that produce deficits in hearing or cognition. Is especially common in English because it has so many words with odd spellings, however it occurs in all languages and always pertains to a difficulty converting symbols into sounds.

Question 55

Describe some contributing anatomical, physiological, and functional factors of dyslexia

Answer 55

More likely to have a bilaterally symmetrical cerebral cortex, whereas in other people, the planum temporale and certain other areas are larger in the left hemisphere.
Several brain areas in the parietal and temporal cortex have less than average gray matter in children with dyslexia and show less arousal during reading.

Most, but not all, have auditory problems, a smaller number have impaired control of eye movements, and some have both.
Dysphonetic dyslexics have trouble sounding out words, so they try to memorize each word as a whole, and when they don’t recognize a word, they guess based on context.
Dyseidetic readers sound out words well enough, but they fail to recognize a word as a whole. They read slowly and have particular trouble with irregularly spelled words.

Auditory problems: brains show less than normal responses to speech sounds, especially consonants. Have particular trouble detecting the temporal order of sounds (like the difference between beep-click-buzz and beep-buzz-click). Have difficulty making spoonerisms.
But cannot simply be impaired hearing because many deaf or partly deaf people can read, and people with dyslexia have no trouble carrying on a conversation. Might be due to paying attention to certain aspects of sound or connecting sound to vision- in one study, were impaired only when they had to look at a nonsense word on the screen and then say whether it was the same as a nonsense word they heard

Abnormalities in their attention: unusually adept at identifying letters well to the right of their fixation point – when they focus on the word, they are worse than average reading it but better than average at perceiving letters 5 to 10° to the right of it.
One effective treatment is to teach them to attend to just one word at a time, such as placing a sheet of paper over the page that they are reading with a window cut out of it that is large enough to expose just one word.

Question 56

What usually gives the most problems to a person with dyslexia – vision, hearing, or connecting vision to hearing?

Answer 56

Generally, the greatest problem arises with connecting visual stimuli to sounds

Question 57

Question about the relationship between mental experience and brain activity

Answer 57

Mind-brain problem or mind-body problem

Question 58

Belief that mind and body are different kinds of substance that exist independently

Answer 58

Dualism

The French philosopher Renée Descartes defended dualism but recognized the vexing issue of how a mind that is not made of material could influence a physical brain. He proposed that mind and brain interact at a single point in space, which he suggested was the pineal gland, the smallest unpaired structure he could find in the brain

Question 59

Belief that the universe consists of only one kind of substance

Answer 59

Monism

Question 60

View that everything that exists is material or physical

Answer 60

Materialism

One version, eliminative materialism, says that mental events don’t exist at all, and any folks psychology based on minds and mental activity is fundamentally mistaken. A more plausible version is that we will eventually find a way to explain all psychological experiences in purely physical terms

Question 61

View that only the mind really exists and that the physical world could not exist unless some mind were aware of it

Answer 61

Mentalism

Question 62

View that mental processes and certain kinds of brain processes are the same thing, described in different terms

Answer 62

Identity position

This position does not say that the mind is the brain, it says the mind is brain activity

Question 63

Describe the decisive objection of dualism

Answer 63

It conflicts with one of the cornerstones of physics, known as the law of the conservation of matter and energy: so far as we can tell, the total amount of matter in energy in the universe has been fixed since the big bang that originated it all. Matter can transform into energy or energy into matter, but neither one emerges from nothing or disappears into nothing. Because matter alters its course only when other matter or energy acts upon it, a mind that is not composed of matter or energy cannot make anything happen, including muscle movements

Question 64

What are the three categories of monism?

Answer 64

Materialism, mentalism, and the identity position

Question 65

Why do nearly all scientists and philosophers reject the idea of dualism?

Answer 65

Dualism contradicts the law of the conservation of matter and energy. According to that law, the only way to influence matter and energy, including that of your body, is to act on it with other matter and energy

Question 66

Philosophical question as to why and how brain activity becomes conscious

Answer 66

Hard problem

In contrast to the easy problems, such as questions about the difference between wakefulness and sleep and what activity occurs during consciousness

Question 67

What is meant by the “hard problem”?

Answer 67

The hard problem is why minds exist at all in a physical world. Why is there such a thing as consciousness?

Question 68

Capable of reporting the presence of a stimulus

Answer 68

Conscious

Question 69

Use of one stimulus to block perception of another

Answer 69

Masking

Question 70

A brief visual stimulus after another brief visual stimulus that leads to failure to remember the first

Answer 70

Backward masking

Question 71

Describe how researchers are trying to discover which types of brain activity are conscious

Answer 71

Researchers used fMRI to record brain activity in patients in vegetative states, such as being told to imagine playing tennis and showing increased activity in the motor areas of the cortex.

Operational definition: If a cooperative person reports awareness of one stimulus and not another, then he or she was conscious.
Using this definition, researchers present a given stimulus under two conditions. In one condition we expect the observer to be conscious of it, and in the other condition we expect the observer to be unconscious of it. In both cases the stimulus excites receptors that send a message to the brain, but once the message reaches the brain presumably something different happens for conscious versus unconscious processing.

Flash suppression: seeing a yellow dot that remains on the screen, while other dots around it flash on and off. While they are flashing you may be unable to see the stationary dot.

Masking – a brief visual stimulus is preceded and followed by longer interfering stimuli. Backward masking – just the later stimulus is presented.
Example: researchers flashed a word on a screen for 29 ms, which on some trials was preceded and followed by a blank screen – people identify the word almost 90% of the time. On other trials, the researchers flashed a word for the same 29 ms but preceded and followed it with masking patterns – people usually say they saw no word at all, and almost never identify it. Using fMRI and evoked potentials show that the stimulus initially activate the primary visual cortex for both the conscious and unconscious conditions but activates it more strongly in the conscious condition. Also, in the conscious condition, the Activity spreads to additional brain areas, including the prefrontal cortex and parietal cortex. Those areas apparently amplify the signal.
A conscious stimulus also synchronizes responses for neurons in various brain areas. One consequence of synchronized action potentials is that their synaptic inputs arrive simultaneously at their target cells, producing maximal summation.

Overall, the data imply that consciousness of a stimulus depends on the amount and spread of brain activity.

Question 72

In the experiment by Dehaene et al., how are the conscious and unconscious stimuli similar? How are they different?

Answer 72

The conscious and unconscious stimuli or physically the same (A word flashed on the screen for 29 ms). The difference was that a stimulus did not become conscious if it was preceded and followed by an interfering pattern

Question 73

In this experiment, how did the brains responses differ between the conscious and unconscious stimuli?

Dehaene experiment where words were flashed on the screen for 29 ms and preceded and followed by either a blank screen or an interfering pattern screen

Answer 73

If a stimulus became conscious, it activated the same brain areas as an unconscious stimulus but more strongly, and then the activity spread to additional areas. Also, brain responses become synchronized when a pattern is conscious

Question 74

When your brain cannot perceive two patterns in the same location, and your perception alternates

Answer 74

Binocular rivalry

Example: looking at a red circle with black vertical stripes and a green circle with black horizontal stripes putting your nose right between them so that one eye sees one circle and the other eye sees the other circle. Your perception alternates because your brain cannot perceive both patterns in the same location – for a while, you see the red and black stripes, and then gradually, the green and black invade your consciousness and so on.

Question 75

How could someone use fMRI to determine which of two patterns in binocular rivalry is conscious at a given moment?

Answer 75

Make one stimulus pulsate at a given rhythm and look for brain areas showing that rhythm of activity. The rhythm takes over widespread areas of the brain when that pattern is conscious

Question 76

If someone is aware of the stimulus on the right in a case of binocular rivalry, what evidence indicates that the brain is also processing the stimulus on the left?

Answer 76

If a stimulus gradually appears on the left side, attention shifts to the left faster if that stimulus is a meaningful word than if it is a word from an unfamiliar language

Question 77

Describe whether consciousness is a threshold phenomenon

Answer 77

One study suggests that consciousness is a yes-no phenomenon: researchers flashed blurry words on a screen for brief fractions of a second and asked people to identify each word and rate how conscious they were of the word on a scale from 0 to 100. People almost always rated a word either zero or 100 and almost never said that they were partly conscious of something, which suggests that consciousness is a threshold phenomenon. When a stimulus activates enough neurons to a sufficient extent, The Activity reverberates, magnifies, and extends over much of the brain. If a stimulus fails to reach that level, the pattern fades

Question 78

Tendency to see something as moving back-and-forth between positions when in fact it is alternately blinking on and off in those positions

Answer 78

Phi phenomenon

Question 79

In what ways does the phi phenomenon imply that a new stimulus sometimes changes consciousness of what went before it?

Answer 79

Someone who sees a dot on the left and then a dot on the right perceives the dot as moving from left to right. The perceived movement would have occurred before the dot on the right, but the person had no reason to infer that movement until after the dot appeared on the right

Another example: a word that sounds halfway between dent and tent, is more likely to sound like dent if the phrase is… In the fender, or tent if the phrase is … In the forest. Later words changed what you heard before them.

Question 80

If something in a complex scene changes slowly, or changes while you blink your eyes, you probably will not notice it unless you were paying attention to the particular item that changes

Answer 80

Inattentional blindness or change blindness

Attention is closely aligned with consciousness – of all that your eyes see at any instant, you are conscious of only those few to which you direct your attention

Question 81

Describe the brain areas controlling attention

Answer 81

Deliberate, top-down direction of attention depends on parts of the prefrontal cortex and parietal cortex

Research: I display with a square in the centre indicating the colour to which the observer should attend with several lines different in colour and orientation around it, participants were asked to identify the line of the indicated colour and then indicate whether or not it was vertical. If the Central Square directed attention to the same colour for many trials in a row, the task was fairly easy. But when the colour switched from one trial to the next, The participant had to alter attention, and the result was increased activity in parts of the prefrontal cortex and parietal cortex.

Question 82

What brain response was related to people’s ability to resist distraction from an irrelevant ted square among the green squares and circle in one research task?

Answer 82

Resistance to distraction related to the amount of activity in part of the pre-frontal cortex before the presentation of stimuli

Question 83

A tendency to ignore the left side of the body or the left side of objects

Answer 83

Spatial neglect

Question 84

Describe the symptoms and physical causes of sensory or spatial neglect?

Answer 84

Spectacular failure of attention often occurs in people with damage to the right hemisphere, who show spatial neglect – a tendency to ignore the left side of the body or the left side of objects.
Also generally ignore much of what they hear in the left ear and feel in the left-hand, especially if they simultaneously feel something in the right-hand. May put clothes on only the right side of the body. Points to the right of centre if I asked to point straightahead, and picks a spot dividing a horizontal line in half well to the right of center, where as people with intact brains generally do not hit the centre of the line, but veer a bit to the left. Also show deviations when estimating the midpoint of a numerical range.

In many cases, the main problem is loss of attention rather than impaired sensation: when one patient was shown an E, composed of small Hs, she identified it as a big E composed of small Hs, indicating that she saw the whole figure. However, when asked to cross off all the Hs, she crossed off only the ones on the right.

Question 85

What is the evidence that spatial neglect is a problem in attention, not just sensation?

Answer 85

When a patient with neglect sees a large letter composed of small letters, he or she can identify the large letter but then neglects part of it when asked to cross off all the small letters. Also, someone who neglects the left-hand pays attention to it when it is crossed over the right-hand.

Question 86

What are several procedures that increase attention to the left side in a person with spatial neglect?

Answer 86

Simply telling the person to attend to something on the left helps temporarily. Having the person look to the left while feeling something on the left side increases attention to the felt object. Crossing the left hand over the right increases attention to the left hand. Moving a hand far to the left makes it easier for the person to point to point to something in the left visual field because the hand will move toward the right to point at the object