Re-cognition Flashcards
Explain the Global Precedence Effect using Navon (1977) stimuli experiment:Pattern recognition
-lots of s letters making up a global/big H
-Global features are typically identified faster (H) than local features (s)
-Global precedence applies more to conscious perception rather than initial visual encoding
Perceptual organisation: Define Perceptual segregation
–Separating visual input/scene into individual objects where the thought to occur before object recognition
What does Gestalt psychology include?
The law of Prägnanz (important but vague and hard to test):
“Of several possible geometrical organisations of one that will actually occur, possesses the best, simplest and most stable shape”
What 4 things does the law of Prägnanz state?
1.Law of proximity:objects that are close together are perceived to belong in the same group
2.Law of similarity:similar objects are perceived to belong in the same group
3.Law of good continuation
4.Law of closure
What’s Figure-ground segmentation?
Figure=object of central interest
Ground=background
What’s Figure-ground segmentation using Faces-goblet illusion?
■Ambiguous drawing that can be seen as two faces or as a goblet
■More attention is paid to the figure than the ground
■Several factors (e.g., colour, luminance) influence figure-ground segmentation
What 2 principles are used in Gestaltism in the real world?
1.Adjacent segments of any contour have very similar orientations
2.Segments of any contours that are further apart have slightly different orientations
■We use knowledge of real objects when making decisions about contours (what we pay attention/focus on)
What do Gestaltists assume about
figure-ground segregation?
-It’s innate BUT memory (i.e., object familiarity) is important
–Healthy controls identify regions including familiar objects as figure whereas amnesic patients do not (showing relevance of memory in FGS)(From Barense et al., 2012, Elsevier)
Give 3 advantages of the Gestalt approach
■It focused on key issues
■Most organisational principles
have stood the test of time (grouping laws are valid)
■Law of Prägnanz has proven
useful as observers strive for
simplicity in visual perception
Give 5 limitations to the Gestalt approach
■Underestimated role of
knowledge (in recognition/paying attention to objects)
■Descriptive rather than explanatory
■Largely based on 2-D drawings
■Little emphasis on complex
interactions among grouping laws (e.g. law of proximity/similarity)
■Too inflexible
How have theories on recognition advanced?: Explain Marr’s theory (it’s a progressive process to how we recognise/perceive things)
Primal sketch:
–2D description of light-intensity (in retina main info perceiving things) changes:Edges, contours and blobs
–Observer-centred(representation perceiving world from person perceiving it)
2½-D sketch:
–Incorporates depth and orientation of surfaces:Shading, texture, motion, binocular disparity, etc.
–Observer-centred
3-D model representation:
– 3-D object shape
– Viewpoint-independent/invariant (from knowing where things are from me and from objects next to it)
How have theories on recognition advanced?: Explain Biederman’s recognition-by-components theory
-Objects consist of combinations of geons (Geometric icons/36 basic shapes)
-Object recognition is viewpoint-invariant (can be identified from any angle) (Biederman & Gerhardstein, 1993)
–Bottom-up processes
Give aspects of the recognition by components theory
1.Aspects of an object invariant across viewing angles
2.Edge straight or curved
3.Contour concave or convex
4.Non-accidental properties can be detected even when part of the target object is concealed by other objects
5.Geons are constructed from non-accidental properties
Recognition-by-components theory: Give 3 strengths
■Good evidence for geons being
important in object recognition
■Evidence the identification of
concavities and edges are also of major importance
■Non-accidental properties can
facilitate viewpoint-invariant
object recognition
Recognition-by-components theory: Give 3 limitations
■De-emphasises top-down influences (e.g., context; expectations; knowledge) even though it influences perception/what you choose to pay attention to
■Fails to account for most within-category discriminations (e.g.,
“Is that a poodle?”)
■Some objects lack invariant geons but are easy to recognise (e.g., clouds)
What’s the influence of viewpoint on object recognition?
■Categorisation of objects (e.g., “Is that a dog?) doesn’t depend on viewpoint
■Identification of objects (e.g., “Is that a bulldog?”) does depend on viewpoint
■With learning, object recognition often becomes increasingly viewpoint-invariant
■With learning, viewpoint dependent and viewpoint-
invariant representations often
both formed in LTM (Tarr & Hayward, 2017)
Explain the Interactive-iterative framework (Baruch et al., 2018)
*There are complex interactions between top-down processes
and bottom-up processes in object recognition
*Hypotheses top-down influences
attention which then influences
bottom-up processes
*Top-down processes more
important with degraded (e.g.,
blurred) stimuli as level of attention required differs
Define Holistic processing
Faces are processed in an integrated manner; it is claimed this is less true of objects
Define the Face inversion effect
Inverted faces are disproportionately harder to recognise than upright faces
relative to objects (Bruyer, 2011)
Define the Part–whole effect
Recognition of a face part more accurate when presented within the whole face (Farah, 1994)
Define the Composite effect
Perceiving half a face is more difficult when it appears against a different complementary half
(Richler et al., 2011)
Define Prosopagnosia and the 2 types
Known as “face blindness”
■Acquired prosopagnosia:caused by brain damage
■Developmental prosopagnosia: no obvious damage (often there’s also impaired object recognition)
What did Busigny et al., 2010 find in Selective “face blindness”
■Patient with acquired prosopagnosia (GG) had intact object recognition for birds, boats, cars etc. but not faces (shows specific brain area which processes faces)
■Thus, GG had a face-specific impairment rather than general
impairment of object recognition
If face recognition involves different processes to object recognition, what do double dissocation do we expect to see?
(1) Some patients with intact face recognition but impaired object recognition
(2) Some patients with intact object recognition but impaired face recognition
■few individuals in category (1)
GG (Busigny et al., 2010); AW (Germine et al., 2010)
■More individuals in category (2)
Geskin and Behrmann (2018): 20% of developmental prosopagnosics had intact object recognition
■Findings suggest face recognition harder than object recognition because it involves finer
discrimination
