Thinking!

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Thinking!

• Psychology 2606

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Some introductory thoughts

• We are clearly the most cognitively complex
  animals on this planet
• We can think about objects that are not present
• We can think about abstract ideas
• We use symbolic and syntactic language
• We plan and string events together

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So, how is thought encoded in the brain?

• Monkeys, dots, motion and V5
• So, individual cortical neurons were detecting
  motion and making decisions
• Hebbs idea of the cell assembly
• The association cortex is key in thought
• Anything not primary is association (that is most
  of the cortex)
• Receives input from the thalamus, but from areas
  that themselves get input from primary sensory
  areas

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Spatial cognition

• Our ability to deal with spatial stimuli may have
  helped us evolve consciousness
• That and the standing up and big heart thing
• We seem to have specialized sub systems to deal
  with different types of information
• Modules if you will

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A Purely Geometric Module in Human Spatial
Representation?

• David R. Brodbeck 1
• Andrea E. Pike 2
• Cory Spracklin 1
• Department of Psychology
• 1-Sir Wilfred Grenfell College, Memorial
  University of Newfoundland, Corner Brook, NL
• 2-Memorial University of Newfoundland, St.
  Johns, NL

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Introduction

• Cheng (1986) got the ball rolling
• Or the cocoa puff, as the case may be
• Basically, he found that rats would use geometric
  information to locate food in a rectangular arena
• Most of their errors were to rotations of the
  originally baited location

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Cheng (1986)

• He then applied featural information
• walls
• corners
• The rats still made errors, though most of these
  were rotational errors
• He concluded that the rats were responding to the
  geometry of the box.

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Hermer and Spelke (1994)

• Tried the Cheng task with toddlers and adults
• Disoriented the subjects
• Using a cue
• Toddlers are not unlike rats
• Adults are different, seem to follow the cue
• Same in Pike (2001)

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Method

• We decided to rotate the object
• A rectangle on a computer monitor
• Subjects (or participants, or whatever..) were
  shown a red dot on a black rectangle
• The rectangle was spun about the middle
• Dot faded
• Where was the dot?

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Uncued Test Results
Original Dot Location 31.0 /- 2.77 Reflection Error 18.2 /- 3.43
Reflection Error 17.4 /- 2.88 Rotational Error 33.4 /- 3.94
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Cued Rectangle Results
Original Dot Location 37.2 /- 3.58 Reflection Error 11.6 /- 3.38
Reflection Error 10.8 /- 2.88 Rotational Error 40.4 /- 3.62
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So what?

• Well, it seems that whenever they can, people
  will use geometry in this task
• Even if there is a reliable cue
• What if we made geometry useless?
• A square

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Uncued Square
Original Dot Location 23.2 /- 2.57 Reflection Error 24.8 /- 3.46
Reflection Error 23.4 /- 2.99 Rotational Error 28.6 /- 4.00
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Cued Square
Original Dot Location 34.2 /- 2.79 Reflection Error 23.2 /- 3.63
Reflection Error 28.0 /- 3.01 Rotational Error 14.6 /- 3.77
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What does it all mean?

• Evidence of a feature independent geometric
  module
• People will use features, if forced
• Under certain circumstances
• Rotational errors disappear when geometry is
  useless
• Errors then become based on the feature

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So, What Does It All Mean?

• Clear evidence (we think) of a feature
  independent, geometric module in human spatial
  processing
• Perhaps if we slowed the rotation we would find
  better performance, and fewer rotational errors
  in the cued condition
• (Rotation was titrated until we found errors
  reliably)

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Future Directions

• Does Length Width follow Webers Law?
• What if the dot was put closer to the centre of
  the stimulus?
• Touch screen
• Hmmm what about pigeons?

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Thanks to
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So we have a spatial module

• It may be the case that input from this spatial
  module, or cell assemblies on top of cell
  assemblies comes together in associative areas
• These modules can be isolated WITHOUT wet
  neurophysiology
• So, the dot is here could be considered a
  thought

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Putting it together

• In the cortex there are columns, individual
  bunches of cells that go across layers of the
  cortex that seem to for circuits together
• Is this the unit of thought?
• Well, it might have something to do with it
• But still, we put all of our sensory and memorial
  thoughts together to form an experience

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We started philosophically, why not end that way

• So, how are all of these things put together into
  an experience?
• The Binding Problem
• This, and the engram may be the holy grails of
  neuroscience and psychology