W1: Recognising Objects

Question 1

In relation to Object Recognition, define form perception and object perception

Answer 1

Forms are perceived, not just as the sum of their parts, but also people process how the form is ranged in depth, which part of the form is figure or ground which is not contained in the stimulus itself

Question 2

What’s the difference between a reversible and ambiguous figures

Answer 2

A Necker cube is a reversible figure (relating to depth), able to be perceived one way or another, but not both at the same time. The lines are neutral in regards to the configuration of depth.
Vase/faeces this relates to ground/figure issues. you can look at either the faces or vase but not both at once.
The interpretation for both images comes from you, not stimulus.

Question 3

Gestalt principles of organisation

Answer 3

Similarity, proximity, good continuation, closure, and simplicity.

Question 4

Simplicity

Answer 4

We tend to interpret the form in the simplest way possible.

Question 5

Closure

Answer 5

Broken triangle is perceived as whole. We prefer to perceive complete figures.

Question 6

Good continuation

Answer 6

If one object partially obscures another, we tend to see the rear object as continuous.

Question 7

Proximity

Answer 7

Dots close together are perceived as groups

Question 8

Similarity

Answer 8

Create groups of similarity (i.e. columns of same coloured dots)

Question 9

How do ‘perception of features’ and ‘analysis of the object’s configuration’ interact?

Answer 9

Features and configuration have to be in place before we can interpret.
Perception of features is guided by configuration and analysis of configuration is guided by features (parallel process)

Question 10

Perceptual constancy

Answer 10

we perceive constant properties of objects in the world even though sensory information changes as our viewing circumstances change. i.e. size, shape, brightness.

Question 11

Describe the two processes that influence object recognition

Answer 11

o Bottom up: data and stimulus driven - look around us and take in the incoming data
o Top-down: concept driven, influenced by context, prior knowledge and concepts

Question 12

Bottom up

Answer 12

data and stimulus driven - look around us and take in the incoming data

Question 13

Top-down

Answer 13

concept driven, influenced by context, prior knowledge and concepts

Question 14

How do visual features contribute to object recognition?

Answer 14

o The vertical lines, curves, diagonals and so on make up the visual features.
o Feature detectors: i.e. detector for the features of the letter ‘A’ which are somewhat flexible.

Question 15

What are the two main factors that influence recognition?

Answer 15

Familiarity and recency

Question 16

What is the experimental technique that we use to study this type of recognition?

Answer 16

Tachistoscope, or tachistoscopic presentations - Brief displays of word stimuli for controlled periods of time (ie 20ms). each stimulus is followed by a mask (hgpxt) - word recognition

Question 17

Define the word superiority effect and describe the technique used to establish it

Answer 17

o Words are easier to perceive than isolated letters.

o Two alternative, forced choice procedure.

Question 18

Why are degrees of well-formedness important in recognition?

Answer 18

Grammatical well-formedness helps you bootstrap what the word would have be..

Question 19

What is a feature net and how does word recognition occur?

Answer 19

Bottom up processing: Feature detectors, letter detectors, word detectors

Question 20

How do bi-gram detectors account for well-formedness?

Answer 20

Theory of activation level, response threshold, recency and frequency
Detectors of letter pairs.
o Step between letter and word detectors
o Well formedness will activate a bigram detector for familiar letter pairing, but not unfamiliar

Question 21

How do we recover from the confusion that may occur in response to briefly presented stimuli?

Answer 21

o At the bigram level
o If we only have partial information about a letter all possible combinations are activated then bigram detectors select the most likely option (frequency/priming)

Question 22

What role does distributed knowledge play in the feature net?

Answer 22

Knowledge is not locally represented it is distributed knowledge, represented in a fashion that is distributed across the network and detectable only if we consider how the entire network functions. i.e., there is no specific ‘CO’ detector site. The whole system is working.

Question 23

How does the McClelland and Rumelhart (1981) model accomplish string recognition without bigram detectors?

Answer 23

Excitatory and inhibitory connections: connections that allow one connector to activate its neighbors. T activates t-words, and inhibits other detectors.
Visual processing is bi-direction.

Question 24

How do people recognise objects in the recognition by components (RBC) model?

Answer 24

o Geons (geometric ions) simple shapes such as cylinders cones and blocks.
o Using a hierarchy of detectors. The lowest level are feature detectors, ie edges curves, vertices. These activate geon detectors which then activate higher level detectors sensitive to higher combinations of geons.
Viewpoint independent. Ie the back of a cat is still recognized as a cat.

Question 25

Why is recognition viewpoint dependent in the recognition via multiple views approach to object recognition?

Answer 25

o Recognition requires mental rotation. Some viewpoints are slower than others. The speed of recognition will be viewpoint-dependent.
o A bottom up hierarchy of detectors, becoming increasingly complex up to the whole object.

Question 26

Why do we think that there is a special recognition system for faces?

Answer 26

o Prosopagnosia seems to imply the existence of special neural structures involved almost exclusively in the recognition of faces.
o Facial recognition is a different process to other recognition thingys.

Question 27

What is the evidence for holistic processing of faces?

Answer 27

Composite face recognition. Difficult if faces are properly aligned.

Question 28

Give an example demonstrating how our knowledge about the world influences our object recognition

Answer 28

Top down is context and prior knowledge. Ie words are easier to recognise if you see them in a sentence,

Question 29

The Necker cube demonstrates which principle of perceptual organisation?

Answer 29

If the input is ambiguous, the image can be interpreted in different ways at different times

Question 30

What best illustrates the effect that Gestalt principles have on perception?

Answer 30

“Go beyond the information given.”

Question 31

Jenna sees a picture of a dog standing in front of a tree. The dog is blocking part of Jenna’s view, so that she cannot see a portion of the tree trunk. Jenna does, however, perceive the tree to have an intact, continuous trunk. Jenna’s perception reminds us that:

Answer 31

People generally “fill in” missing perceptual information, guided by the Gestalt principles

Question 32

Despite the fact that sensory stimuli can change from moment to moment, we perceive the details (colour, shape, etc.) of an image to be stable because of:

Answer 32

Constancy

Question 33

What underlies the achievement of perceptual constancy?

Answer 33

Unconscious inference

Question 34

What best describes Visual illusions?

Answer 34

Cognitive principles that generally help us can cause illusions in some cases.

Question 35

What sort of processing is driven primarily by factors in the environment or in the stimulus itself?

Answer 35

Bottom Up.

Question 36

Which task is likely to produce the longest reaction time in an experiment requiring participants to quickly determine if a target is present?

Answer 36

Identifying a red vertical line in a field of red horizontal and blue vertical lines.

Question 37

What does a Tachistoscope device do?

Answer 37

Display stimuli for precisely controlled exposure times.

Question 38

What is an example of word superiority effect?

Answer 38

HAFE > HZYE

Question 39

participants have been shown non-word letter strings, presented very briefly. When asked to identify these strings, participants tend to make specific kinds of errors. How would these errors be best described?

Answer 39

They tend to misidentify strange letter combinations as more-common letter combinations.

Question 40

Participants’ recognition thresholds are…

Answer 40

lower for frequently seen words.

Question 41

We sometimes encounter ambiguous letters when reading handwritten words, but we can still interpret the words. For example, the same shape can be interpreted as an A in CAT but an H in THE. At what level of analysis does the feature net resolve this issue?

Answer 41

At the word level.

Question 42

Knowledge of some sorts is likely to be represented by a broad pattern of activation spread across a network which represents…

Answer 42

Distributed representation

Question 43

Mistakes in word recognition occur within a feature net model of recognition. One reason is feature net encourages ________ over ________.

Answer 43

Efficiency over accuracy

Question 44

What is the term “geons” short for?

Answer 44

Geometric ions

Question 45

What best describes viewpoint-dependent object recognition?

Answer 45

The perceiver must match the current view of an object with a view of the object stored in memory, often using the process of rotation.

Question 46

Brain damage identified as Prosopagnosia disables what?

Answer 46

Inability to recognise faces.

Question 47

Facial recognition depends on the configuration and spacing of the features, which reflects what type of processing?

Answer 47

Holistic

Question 48

Priming effects do what?

Answer 48

• Change in response to a stimulus caused by exposure to an identical, similar, or related stimulus;
• Impact the words we perceive;
• Can meaningfully impact our understanding of situations.

Question 49

What are bigram detectors?

Answer 49

Detectors of letter pairs.

Question 50

What is repetition priming?

Answer 50

When the test stimulus is the same as or resembles the priming stimulus

Question 51

McClelland and Rumelhart Model

Answer 51

A model referring to excitatory and inhibitory connectors involved in pattern recognition.

Question 52

recognition by components theory

Answer 52

a specific view of an object can be represented as an arrangement of simple 3-D shapes called geons (geometric icons).