PSY270H1 Lecture Notes - Lecture 3: Temporal Lobe, Long-Term Memory
Lecture 3:
(came late and missed notes up to Gestalt principles for solving ambiguity) – Check slides
Gestalt psychologists identified a set of assumptions (heuristics) that the visual system tends to
make when performing figure ground segregation.Heuristics – Mental shortcuts (implicit rule
of thumb almost)
Similarity: points which share features are grouped togetherClosure: Points form closed
(whole) objectsProximity: Points close in space are grouped togetherGood Continuation:
Points are assumed to be connected by smooth lines Good Figure/Simplicity: every stimulus is
seen as being as simple as possible
Environmental Regularities:
Physical Regularities: regularly occurring physical properties of the environmentLight from
above assumption; Assume that 3D objects are lit from aboveOblique effect: People are better
at processing horizontal and vertical lines because they are more common than oblique (caused
by neural plasticity: see textbook).Semantic Regularities: the characteristics associated with
functions carried out in different types of scenesScene schema experiment: [Palmer, 1975]:
flash quick scenes and ask for object recognize, participants recognize schema consistent
objects (bread) 80% of time but incongruent objects (mailbox) only 40% of the time.
Size and Distance:
The retinal size of an object is determined by its size and distance. How can we tease them
apart? I.e: how do we tell the difference between a small tree which is close and a large tree
which is far.
Monocular Depth/Distance Cues:
Familiar Size – we tend to know what size things should be.Occlusion and Interposition – I.e.:
is one thing blocking another thingTexture Gradient: The texture of things helps us determine
their locationLinear Perspective: I.e.: looking at two parallel lines, the further out they go they
appear to converge together.Relative size/height: two similar objects might have the same
size, so if one appears a lot smaller the assumption is that it is further away.
Binocular Depth/Distance Cues:
Convergence: the extent to which your eyes are turned inward to fixate on an object.. Your
eyes point inwards when looking at very close by objects. Only works for short distances (up to
about a meter).
Stereopsis/retinal disparity: the difference in image projected to the left and right eye. Can trick
your eyes into thinking flat images have depth to them. Used to make 3D movies appear 3D.
Challenges:
We identify the shape and, size, and location of an object by performing inferences on retinal
input.
But how do we recognize an object?The image received by our brains still comes in many
shapes and sizes based on our perspective.
Theories of object recognition:
Objected Centered Theories – Propose that we store one 3D template for each object (part +
their relationship).
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Document Summary
Lecture 3: (came late and missed notes up to gestalt principles for solving ambiguity) check slides. Gestalt psychologists identified a set of assumptions (heuristics) that the visual system tends to make when performing figure ground segregation. Heuristics mental shortcuts (implicit rule of thumb almost) Similarity: points which share features are grouped together closure: points form closed (whole) objects proximity: points close in space are grouped together good continuation: Points are assumed to be connected by smooth lines good figure/simplicity: every stimulus is seen as being as simple as possible. The retinal size of an object is determined by its size and distance. I. e: how do we tell the difference between a small tree which is close and a large tree which is far. Familiar size we tend to know what size things should be. Occlusion and interposition i. e. is one thing blocking another thing texture gradient: the texture of things helps us determine their location linear perspective: i. e.
