Chapter Seven The Other Sensory Systems and Attention

1
Chapter Seven The Other Sensory Systems and
Attention
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
1 of 49
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Sound and the Ear
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
2 of 49

• Sound waves are periodic compressions of air,
  water or other media
• we hear when the sound waves strike our ear
• Sound waves vary in amplitude and frequency
• amplitude of a wave is the intensity (amplitude
  must double before it is perceived louder)
• frequency is the number of waves per second (if
  frequency increases we perceive an increase in
  pitch)
• We can hear 15 to 20,000 hertz (Hz, cycles per
  second)
• ability to hear high frequencies falls off with
  age and repeated loud noises
• mice and other small animals can hear higher
  frequencies

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Figure 7.1
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
3 of 49

• Figure 7.1  Four sound waves. The time between
  the peaks determines the frequency of the sound,
  which we experience as pitch. Here the top line
  represents five sound waves in 0.1 second, or 50
  Hza very low-frequency sound that we experience
  as a very low pitch. The other three lines
  represent 100 Hz. The vertical extent of each
  line represents its amplitude or intensity, which
  we experience as loudness.

4
Structures of the Ear
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
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• Outer ear or pinna
• cartilage attached to the side of the head that
  alters reflections and helps us locate sounds
• Middle ear
• the tympanic membrane or eardrum vibrates at the
  same frequency as incoming sound wave
• middle ear bones, hammer, anvil and stirrup
  provide 201 step down of vibration
• increases force on oval window of inner ear

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Structures of the Ear cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
5 of 49

• Inner ear or cochlea
• vibration on oval window, membrane leading to
  inner ear, moves fluid in three fluid-filled
  tunnels
• scala vestibuli
• scala media
• scala tympani
• Fluid moves basilar membrane across tectorial
  membrane and this excites hair cells
• hair cells sensitive to movement of 0.1 nanometer
  or more
• Hair cells excite cells of auditory nerve

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Figure 7.2
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
6 of 49

• Figure 7.2  Structures of the ear. When sound
  waves strike the tympanic membrane in (a), they
  cause it to vibrate three tiny bonesthe hammer,
  anvil, and stirrupthat convert the sound waves
  into stronger vibrations in the fluid-filled
  cochlea (b). Those vibrations displace the hair
  cells along the basilar membrane in the cochlea.
  (c) A cross section through the cochlea. The
  array of hair cells in the cochlea is known as
  the organ of Corti. (d) A closeup of the hair
  cells.

7
Pitch Perception
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
7 of 49

• Frequency theory
• basilar membrane vibrates at same frequency of
  sound, causing auditory neurons to produce action
  potentials at the same frequency.
• but, neurons cant fire above 1000 Hz
• Place theory
• each area of basilar membrane vibrates to a
  different frequency
• but, basilar membrane is bound together and no
  part can vibrate separately

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Figure 7.4
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
8 of 49

• Figure 7.4 The basilar membrane of the human
  cochlea. High-frequency sounds produce their
  maximum displacement near the base. Low-frequency
  sounds produce their maximum displacement near
  the apex.

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Pitch Perception cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
9 of 49

• Current theory
• up to 100Hz, basilar membrane vibrates in
  synchrony and auditory neurons produce one action
  potential per wave
• at higher frequencies neurons fire only to some
  of the waves but are phase locked to peaks of
  cells
• Volley principle
• the auditory nerve as a whole can have volleys of
  impulses up to about 4,000 Hz per second
• most hearing above 4,000 Hz not important in
  human speech or music

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Pitch Perception in the Cerebral Cortex
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
10 of 49

• Auditory pathway
• output of inner ear goes to several subcortical
  structures
• crossover occurs at midbrain so that each
  hemisphere of forebrain gets major input from
  opposite ear
• Primary auditory cortex
• a cell responds best to one tone and cells
  preferring a given tone cluster together
• damage impairs ability to recognize complex
  sounds such as music or conversation simple
  sounds not affected

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Pitch Perception in the Cerebral Cortex cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
11 of 49

• Secondary auditory cortex
• each cell responds to a complex combination of
  sounds
• Ventral and Dorsal Pathways
• ventral pathway to prefrontal cortex tells what
  the sounds represent
• dorsal pathway to prefrontal cortex tells where

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Figure 7.5
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
12 of 49

• Figure 7.5 Route of auditory impulses from the
  receptors in the ear to the auditory cortex. The
  cochlear nucleus receives input from the
  ipsilateral ear only (the one on the same side of
  the head). All later stages have input
  originating from both ears.

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Figure 7.6
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
13 of 49

• Figure 7.6 The human primary auditory cortex.
  Cells in each area respond mainly to tones of a
  particular frequency. Note that the neurons are
  arranged in a gradient, with cells responding to
  low-frequency tones at one end and cells
  responding to high-frequency tones at the other
  end.

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Hearing Loss
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
14 of 49

• Conductive or middle ear deafness
• bones of the middle ear fail to transmit sound
  waves but normal cochlea and auditory nerve
• caused by tumors, infection, disease
• usually corrected by surgery or hearing aids
• can hear own voice as sounds bypass the middle ear

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Hearing Loss cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
15 of 49

• Nerve or inner ear deafness
• damage to cochlea, hair cells or auditory nerve
• usually treated with hearing aids if no extensive
  damage
• caused by genetics, disease, ototoxic drugs,
  repeated exposure to loud noises, inadequate
  thyroid gland, etc.
• tinnitus, ringing in the ears, common in old age
  with loss of high frequency hearing
• with loss of cochlea output to forebrain, other
  axons may invade areas responsive to sound

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Localization of Sound
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
16 of 49

• At high frequencies, your head creates a sound
  shadow
• sound is loudest in nearest ear
• wavelength much shorter than width of head most
  accurate between 2-3000 Hz
• Low frequencies create phase difference
• sounds arrive out of phase dependent on low
  frequencies where wavelength is less than width
  of head
• accurate up to about 1500 Hz

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Figure 7.9
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
17 of 49

• Figure 7.9 Phase differences between the ears as
  a cue for sound localization. Note that a
  low-frequency tone from straight ahead (a)
  arrives at the ears slightly out of phase. A tone
  that arrives at an angle (b) can arrive in
  different phases at the two ears. With
  high-frequency sounds the phases can become
  ambiguous.

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Localization of Sound cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
18 of 49

• Time of arrival
• arrives at one ear first
• about 600 ms delay when sound comes directly from
  side
• good for sudden onset of sound
• Mice
• small head provides poor localization of low
  frequencies
• good sound shadow for accurate localization of
  high frequencies
• Elephant
• large head good localization of low frequencies
• but, upper limit of hearing at 10,000 Hz

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The Mechanical Senses
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
19 of 49

• Mechanical senses respond to pressure, bending,
  or other distortions of a receptor
• Vestibular organ monitors movement of head,
  directs eye compensation and maintains balance
• when head tilts, two otolith organs, utricle and
  saccule push against different hair cells
• also, when head moves, jelly-like substance in
  three semicircular canals cause bending of hair
  cells
• action potentials from cells travel through 8th
  cranial nerve to brain stem and cerebellum

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Figure 7.10
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
20 of 49

• Figure 7.10 Structures for vestibular sensation.
  (a) Location of the vestibular organs. (b)
  Structures of the vestibular organs. (c) Cross
  section through an otolith organ. Calcium
  carbonate particles, called otoliths, press
  against different hair cells depending on the
  direction of tilt and rate of acceleration of the
  head.

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Somatosensation
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
21 of 49

• Somatosensory receptors vary in complexity and
  stimuli that they respond to, e.g.
• Pacinian corpuscle detects sudden displacements
  or high-frequency vibrations on the skin
• Meissners corpuscles
• elaborate neuronal endings detect sudden
  displacement and low frequency vibrations on skin
• free nerve endings detect pain, warmth and cold
• Ruffini endings detect stretch of skin
• Merkels disks detect indentation of skin

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Somatosensation cont
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
22 of 49

• Input to the spinal cord and the brain
• touch information from head enters CNS through
  cranial nerves
• below the head, information enters via 31 spinal
  nerves connecting to 31 dermatomes
• sensory pathways to cortex remain separate
• Ex two parallel strips respond to light touch,
  two others respond mostly to deep touch and
  movement of the joints and muscles
• somatosensory cortex receives input from the
  contralateral side of the body

23
Figure 7.14
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
23 of 49

• Figure 7.14  Dermatomes innervated by the 31
  sensory spinal nerves. Areas I, II, and III of
  face are not innervated by the spinal nerves, but
  instead by three branches of the fifth cranial
  nerve. Although this figure shows distinct
  borders, the dermatomes actually overlap one
  another by about one-third to one-half of their
  width.

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Pain
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
24 of 49

• Transmission
• for moderate pain axons release glutamate
• stronger pain axons release glutamate and
  substance P
• mice without substance P cannot detect severe
  injury

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Pain cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
25 of 49

• Opoid mechanisms in brain reduce pain
• endorphins, e.g., neurotransmitters
  met-enkephalin and leu-enkephalin, bind to opiate
  receptors
• endorphins are stimulated by pain, especially
  inescapable pain, sex, long-distance running and
  thrilling music
• supports gate theory of pain that non-pain
  stimuli can reduce pain
• Endorphins released in the periaqueductal gray
  area results in blocking release of substance P,
  reducing pain

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Figure 7.15
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
26 of 49

• Figure 7.15  Synapses responsible for pain and
  its inhibition. The pain afferent neuron releases
  substance P as its neurotransmitter. Another
  neuron releases enkephalin at presynaptic
  synapses the enkephalin inhibits the release of
  substance P and therefore alleviates pain.

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Painful Heat
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
27 of 49

• Body has special heat receptors that respond to
  burns or high heat above 43 degrees centigrade
• capsaicin stimulates heat receptors and causes
  neurons to release substance P, increasing pain
• but, capsaicin leaves you temporarily insensitive
  to pain because neurons are quickly depleted of
  substance P

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Pain and Emotion
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
28 of 49

• Hurt is an emotion
• we can ignore serious injury at times, e.g.,
  soldier in battle
• placebo, drug with no effect, can relieve pain
  anesthesia
• also, analgesic is more effective when you know
  it is being given

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Pain and Emotion cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
29 of 49

• Cingulate cortex reacts to emotional aspect of
  pain, not the sensation
• painful stimulus to skin results in response
• no response to pin prick when person is told it
  will not hurt
• expectation of pain leads to response to
  moderately warm stimulus
• when damaged in rats, they will react to pain on
  foot but will not learn to avoid the place where
  it was received

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Sensitization, Pain Control and Itching
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
30 of 49

• Damaged tissue increases number of sodium gates
  in nearby receptors to magnify pain
• facilitates activity at capsaisin receptors,
  increasing pain
• anti-inflammatory drugs, e.g., ibuprofen,
  decrease pain by reducing the release of
  chemicals from damaged tissues
• Morphine for pain control
• very effective it reducing serious pain
• post-surgical use recommended

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Sensitization, Pain Control and Itching cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
31 of 49

• Itch
• caused by release of histamines when skin is
  irritated
• inhibitory relationship with pain, e.g., when
  novocaine wears off, you feel itch but face is
  still numb

32
Chemical Senses
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
32 of 49

• Sensory and auditory systems operate on principle
  of across fiber pattern coding
• each receptor responds to a wider range of
  stimuli and contributes to the perception of them
• Ex only three types cones in retina but ratio of
  three responses determines many colors
• Ex hair cell receptors respond to certain
  frequency tone and in phase with a number of
  tones
• Also, in taste and smell systems, the meaning of
  a particular response by a receptor depends on
  the context of responses by other receptors

33
Taste
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
33 of 49

• Taste influenced by smell
• lose sense of smell and taste is impaired
• Taste receptors
• modified skin cells that are sloughed off and
  replaced every 10-14 days
• also, like neurons, they have excitable membranes
  and release neurotransmitters
• in taste buds, located in papillae
• mainly along outside edge of tongue
• some on tip and posterior third of tongue
• virtually nonexistent in center of tongue

34
Figure 7.18
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
34 of 49

• Figure 7.18  The organs of taste. (a) The tip,
  back, and sides of the tongue are covered with
  taste buds. Taste buds are located in papillae.
  (b) Photo showing cross section of a taste bud.
  Each taste bud contains about 50 receptor cells.

35
Taste cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
35 of 49

• At least 4-5 kinds of taste receptors and their
  mechanisms
• sweet, bitter, and, likely, umami (glutamate)
• receptors operate much like a metabotropic
  synapse activating a G protein that releases a
  second messenger within cell
• salty detects the presence of sodium
• the higher the concentration the stronger the
  response
• sour closes potassium channels preventing
  potassium from leaving the cell creating a
  depolarization

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Taste cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
36 of 49

• Taste adaptation
• decreased sensation from repeated stimulus
• Ex soak your tongue in sour solution and then
  other sour solutions taste less sour
• Cross adaptation reduced response in one taste
  after exposure to another but very little
  adaptation across the five tastes

37
Taste cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
37 of 49

• Coding of taste depends on a pattern of responses
  across fibers, e.g. sweetness excites sweet
  receptors and other receptors to determine how
  sweet substance is
• Anterior two-thirds of tongue carried to brain by
  chorda tympani, a branch of 7th cranial nerve
• loss of taste here and the posterior of tongue
  would still provide taste sensations and would be
  more sensitive to bitter, somewhat more sensitive
  to sour and sweet, and less to salt
• posterior becomes more active and may release
  tastes when nothing is there

38
Taste cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
38 of 49

• Taste nerves project to nucleus of the tractus
  solitarius (NTS) in medulla
• then branches to the pons, the lateral
  hypothalamus, the amygdala, the ventral-posterior
  thalamus,
• and two areas of cortex, one for taste and one
  for sense of touch

39
Taste cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
39 of 49

• Differences in taste
• some people have a gene for tasting
  phenythiocaramide (PTC) and others do not
• nontasters also less sensitive to bitter, sour,
  salt tastes
• supertasters have highest sensitivity to all
  tastes
• Unlikely to enjoy black coffee, strong beer, tart
  fruits, dark bead, brussels sprouts, cauliflower,
  etc.

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Figure 7.19
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
40 of 49

• Figure 7.19  Major routes of impulses related to
  the sense of taste in the human brain. The
  thalamus and cerebral cortex receive impulses
  from both the left and the right sides of the
  tongue. (Source Based on Rolls, 1995).

41
Olfaction
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
41 of 49

• Cilia (dendrites) of receptors extend to mucous
  of the sinus
• receptors survive for little over a month and are
  replaced
• rapid adaptation to scent
• each receptor axon sends impulses to olfactory
  bulb
• each odor excites same receptors and same part of
  olfactory bulb
• Olfactory bulb sends axons to precise areas of
  cortex
• each odor sends information to same cluster of
  cells

42
Figure 7.21
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
42 of 49

• Figure 7.21 Olfactory receptors. (a) Location of
  receptors in nasal cavity. (b) Closeup of
  olfactory cells.

43
Olfaction cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
43 of 49

• Identifying olfactory receptors
• people have specific anosmias for isobutyric
  acid, and musky, fishy, urinous and malty odors
• perhaps 26 other specific types of anosmia
• one receptor can identify approximate nature of
  odor
• a family of proteins have been identified within
  receptors
• its estimated that humans have several hundred
  proteins
• mice have about 1000 proteins and can distinguish
  odors that seem the same to humans

44
Vomeronasal Organ (VNO)
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
44 of 49

• Located near olfactory receptors but structurally
  different
• Receptors respond only to pheromones, chemicals
  released by animal that affects sexual behavior
  of other animals
• Tiny in adult humans but responds to skin
  secretions
• cause increased activity in hypothalamus, area
  important for sexual behavior
• women who spend time together have synchronized
  menstrual cycles
• Intimate relationships increase regularity of
  menstrual cycle

45
Attention
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
45 of 49

• Sight or sound too brief to register in conscious
  still has effect
• brief smiling (or frowning) face causes facial
  muscles to start to smile (or frown)
• related words are identified quicker
• unmasked stimuli reach consciousness, masked do
  not
• Strong stimuli enter consciousness from bottom
  up by arousing brain and focusing attention
• Conscious focusing of attention is a top down
  process

46
Neglect
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
46 of 49

• We can see, hear, touch and smell more if we
  direct our attention to those areas
• person with damage to auditory cortex could
  report start and stop of sounds when asked to do
  so
• persons with spatial neglect of left side of body
  can still focus attention on left side using top
  down processes
• simply tell them to pay attention, look left, or
  feel something with left hand
• crossing left and right hands increases awareness
  of left side
• very difficult to attend to two items presented
  closely together

47
Attention-Deficit Hyperactivity Disorder (ADHD)
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
47 of 49

• ADHD symptoms include distractibility,
  hyperactivity, impulsivity, mood swings, short
  temper, vulnerability to stress and difficulty
  planning
• affects school performance and social behavior
  lifelong
• 3-10 of children (and fewer adults) diagnosed
  with ADHD, 2-3 times more often in males
• very difficult to make reliable diagnosis

48
Attention-Deficit Hyperactivity Disorder (ADHD)
cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
48 of 49

• Measured characteristics of person with ADHD
• less likely to delay gratification when given
  opportunity of greater reward later
• difficulty inhibiting behavior if decision is
  required quickly
• more difficulty shifting attention quickly
• Causes
• higher incidence in families, suggesting high
  heritability
• 95 of normal brain volume with smaller right
  prefrontal cortex and cerebellum

49
Attention-Deficit Hyperactivity Disorder (ADHD)
cont.
James W. Kalat
Biological Psychology, 8th Edition
Chapter 7 The Other Sensory Systems and
Attention
49 of 49

• Most common treatment is stimulant drugs Ritalin
  or amphetamine
• increases attentiveness, school performance and
  social relationships and decreases impulsiveness
• helps adults pay better attention to driving,
  avoid tickets and reduce irritability toward
  other drivers
• increases availability of dopamine for about
  three hours
• also increases attention span of so-called normal
  children