The document discusses perception and its development. It covers topics like the functions of perception including acquiring sensory information and maintaining models of the environment. It also discusses attention, localization of objects, recognition, abstraction, perceptual constancies, and the neural basis of perception. Regarding development, it notes that both nature and nurture influence perception and that infants can discriminate forms, depth, and constancies from a very young age, but these capacities continue developing into childhood. Controlled stimulation studies found both absence and limited stimulation can impair innate perceptual abilities.

1. Chapter 5
Perception
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

2. What is the Use of Perception?
• Processing & using incoming sensory information
– Humans require models of the environment to base
perceptions, decisions and behaviour on
– To create & maintain models, they need to acquire raw
sensory information & organize this into a coherent
structure
• Five functions of perception
– Need to decide which information to process, where
object of interest is, recognise what object of interest is,
abstract the critical features of the object and keep
appearance of the object constant
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

3. Attention
• Selective attention
– Refers to the process by which we attend to certain
stimuli and ignore others
– Eye movements – studies of visual attention monitor
people’s eye fixation patterns which attend to features
most likely to distinguish scene for other similar scenes
• Auditory attention
– Also use selective attention in audition, e.g. by focusing
on the direction the sound is coming from and features of
the speaker’s voice, e.g. pitch and intonation
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

4. Attention
• Attention, perception, and memory
– We are consciously unaware of, and remember little
about unattended stimuli
• Costs & benefits of selectively attending to stimuli
– One cost of selective attention is that observers are
often oblivious to other, potentially important, stimuli in
the environment
– That people are able to switch attention between sets
of information can be beneficial e.g. in medicine for the
treatment of cataracts
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

5. Localization
• To localize objects, need to first separate them and then
organise them into groups
• Separation of objects
– Figure and ground – in stimulus with two or more distinct
regions, usually see part as figure (contains objects of
interest) and rest as ground (or background)
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

6. Localization
• ...Separation of objects
– Grouping of objects - according to several determinants
– proximity to each other, similarity, good continuation or
closure. These serve to create most stable and simple
forms possible within a given pattern
• Perceiving distance
– To know where object is, we use depth cues
• Binocular cues – brain uses information from eyes to infer depth
• Monocular cues – for distant objects we use environmental
information e.g. perspective, interposition, relative size & height,
shading & shadows and motion
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

7. Localization
• Perceiving motion
– To move around environment effectively need to
know direction of moving objects either using
stroboscopic motion (illusion of motion) or real motion
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Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

8. Recognition
• Recognising object requires that the features of
an object are correctly bound together
• Global-to-local processing
– To know what object is, use the context (the scene) to
make inferences – global processing (what the scene
is) followed by local processing (using knowledge
about scene to identify object)
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

9. Recognition
• The binding problem: pre-attentive & attentive
processes
– Feature integration theory – information about primitive
features of an object acquired via pre-attentive
processes, and then integrated in subsequent attentive
processing stage (using attention to “glue” features
together)
– Problems with the feature integration theory because
research has found too many “primitives” to be
realistic. Dynamic control theory proposed – system
rearranges itself for different tasks
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

10. Recognition
• Determining what an object is
– Shape plays critical role in determining what object is
– Visual processing – early stages use information on
the retina to create description, later stages use
comparison with visual memory to select best match
– Feature detectors in the cortex – three types of cell
• Simple cells – respond when eye exposed to line stimulus at
particular orientation and position within receptive field
• Complex cells – also respond to bar or edge in particular
orientation but do not need specific position
• Hypercomplex cells – require stimulus to be in a particular
orientation and of particular length
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

11. Recognition
• ...Determining what an object is
– Relations among features – to describe a shape also
need to specify how features combine/relate
• Later stages of recognition: network models
– Simple networks – knowledge of features associated
and not associated with shapes contained in network of
connections (connectionist model) for comparison
– Networks with feedback – easier to perceive letter as
part of word than alone because the word is an
additional source of activation for letter – therefore have
top-down feedback connections which aid recognition
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

12. Recognition
• Recognising natural objects & top-down processing
– Features of natural objects
• More complex than lines – similar to simple geometric forms, e.g.
cylinders, cones, blocks and wedges. Particular set of such
forms is a geon
– The importance of context
• Bottom-up processes driven solely by the input (sensory data),
whereas top-down processes driven by person’s knowledge,
experience, attention and expectations
• When the context is appropriate (that is, it predicts the input
object), it facilitates perception; when the context is inappropriate,
it impairs perception
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

13. Recognition
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

14. Recognition
• Special processing of socially relevant stimuli:
face recognition
– Development of special face recognition processes
• Three sources of evidence – prosopagnosia – brain injury
where person able to recognise objects but not faces;
inversion effect – faces hard to recognise upside down but
not objects; and face and object recognition develop
differently in children
– Failure of recognition – happens routinely for people
with certain kinds of brain damage (agnosia)
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

15. Abstraction
• Exact to abstract
– Only need to know enough visual detail to carry out
whatever task is requiring you to perceive the object
• The advantages of abstraction: required storage
and processing speed
– More efficient to perceive and encode an abstraction
of an object than exact representation in memory
– Because abstraction uses less space, faster to work
with
– Information retained is the critical information needed
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

16. Perceptual Constancies
• The nature of constancy
– What we perceive is perception of what object is
actually like rather than perception based only on the
“objective” physical information acquired from
environment
• Color and brightness constancy
– Color constancy – ability of visual system to perceive
the reflectance characteristic (an inherent property of
the object) – no matter what the source wavelengths
(light source – sun/light bulb etc.)
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

17. Perceptual Constancies
• ...Color and brightness constancy
– Brightness constancy – perceived lightness of object
changes very little (if at all) even when intensity of
source changes significantly
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

18. Perceptual Constancies
• Size constancy
– An object’s perceived size remains relatively constant
no matter how far away it is
– Dependence on depth cues – perceived size of an
object increases with both the retinal size of the
object and the perceived distance of the object
(known as the size-distance invariance principle)
• Constancies in all sensory modalities
– Although visual constancies most salient, constancies
exist in all sensory modalities
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

19. Perceptual Constancies
• Illusions
– Perception differs systematically from physical
reality, often because visual system tries to
maintain constancy
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

20. Divisions of Labor in the Brain
• The neural basis of attention
– Three brain systems in attention
• One system functions to keep us alert while the other two
systems seem to mediate selective attention, the first
(posterior system) by orienting attention to the stimulus on
basis of location, shape or color, while the second (anterior
system) controls when and how these features will be used
for selection
– Neural processing on attended objects
• Regions of the brain that are relevant to attribute being
attended to (e.g. color) will show increased activity
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

21. Divisions of Labor in the Brain
• The visual cortex
– Visual cortex operates according to the principle of
division of labor – different regions specialised for
different perceptual functions
• Recognition versus localization systems
– Recognition depends on branch of visual system
which includes primary visual cortex and a region
near the bottom of the cerebral cortex, while
localization depends on branch of visual system
which includes primary visual cortex and a region of
the cortex near the top of the brain
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

22. Perceptual Development
• Nature and nurture
– Research seeks to assess contribution of nature and
nurture in perceptual development and identify
interactions
• Discrimination by infants
– Methods of studying infants
• Preferential looking method – infant’s tendency to look at
some objects more than at others
• Habituation method – allow infants to look at an object until
bored (habituated to it) and then present new object and
measure time looking at it
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

23. Perceptual Development
• ...Discrimination by infants
– Perceiving forms
• Visual acuity develops rapidly over the first six months, then
more slowly until reaches adult levels between 1-2 years
• Sensitivity to some shape features of objects appears very
early in life, e.g. three-day-old infant will direct eye
movements to edges when presented with triangle
– Perceiving depth
• Depth perception begins to appear at three months but not
fully established until about six months
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

24. Perceptual Development
• ...Discrimination by infants
– ...Perceiving depth
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

25. Perceptual Development
• ...Discrimination by infants
– Perceiving constancies
• Also starts to develop in first few months of life, particularly
for shape and size constancy
• Controlled stimulation
– Absence of stimulation
• Animals raised in darkness suffered permanent visual
impairment suggesting that there is a critical period early in
life when lack of normal stimulation produces deficiency in
innate perceptual capacities
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning

26. Perceptual Development
• ...Controlled stimulation
– Limited stimulation
• Animals receive stimuli in both eyes but only certain kinds –
leads to deficiency in stimuli they do not receive. Facts
indicate that certain kinds of stimulation essential for
development and maintenance of perceptual capacities
present at birth
– Active perception
• Learning plays major role for coordinating perceptions with
motor responses
Use with Atkinson & Hilgard’s Introduction to Psychology 15th edition
Nolen-Hoeksema, Fredrickson, Loftus, Wagenaar
ISBN 9781844807284 © 2009 Cengage Learning