psychology essay
Minfu Liang
01_Introduction.pdf
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Goals of this course… • Outline the basics of our visuospatial perceptual systems
• Establish and evaluate the two main competing theories of representation and cognition – symbolic and non- symbolic / embodied.
• Investigate cognitive processes and how they relate to the embodied experiences of visual and spatial perception
• Explore the symbol grounding problem and the nature of “understanding” something
• Discuss the current and future state of cognitive science as a discipline
• Expand your mind dude
How to succeed in this course 1. Come to class engaged and prepared to think
2. Ask questions when things are unclear • Do NOT hesitate! If no questions are asked, I’ll assume it’s
understood.
3. Don’t get caught up in writing down everything I say – take notes strategically • I will audio record and post my lectures, unless this is abused • A good strategy – one sentence per slide summing up takeaway point • Focus on ENGAGING with the material, not mindlessly copying me
4. Keep up with all readings • Readings are fair game on RPPQs • I’ll make sure to give you a discussion section in between when the
reading is assigned and when it is quizzed on
5. Take advantage of discussion sections • You can go over readings and discuss your projects and homework
here
6. Get an early start on your project proposal
7. Review material every weekend
Introduction to Visual and Spatial Cognition
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Close your eyes and relax…
How did you answer these questions? • Did any visual imagery come to mind while
answering these questions? How much did you “will” this?
• Did you imagine what it would be like to actually be there, or do the action? How real did this seem?
• Can you imagine things you’ve never done?
• Why is blue “cold”?
• When adding apples, did you visualize the apples? Did you intend to do this, or did you just do it?
• When solving the second math problem, how did you keep track of the numbers?
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Visual and Spatial Cognition • The idea that our visual perception, bodily
perception, spatial awareness, and sensorimotor abilities are involved with (necessary for?) cognition.
• How “thinking” utilizes perceptual processes, especially visual and spatial ones
• How “thinking” utilizes motor processes, specifically moving through and interacting with an environment
What is mind?
Mind-Body Problem • Dualism – Mind and body are
separate entities.
• “Although I possess a body with which I am very intimately conjoined. . . . it is certain that this (that is to say, my soul by which I am what I am) is entirely and absolutely distinct from my body, and can exist without it.”
-Descartes
• “Since our inner experiences consist of reproductions, and combinations of sensory impressions, the concept of a soul without a body seem to me to be empty and devoid of meaning. ”
- Einstein
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Penfield Experiment
Desmurget et al., 2009
Artificial Intelligence
• If dualism is wrong, and mind is not some ethereal quality…
• Then we should be able to build an artificial brain, and therefore an artificial mind.
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Turing and Computers
• Turing machine – theoretical computer that can calculate anything calculable.
• Given an input and a current state, provides proper output.
Brains as Turing Machines? • Input comes in • Input represented as
symbols (in this case, binary values)
• Symbols operated on according to rules (and based on state of the system)
• Rules transform input symbols into output symbols
• Information is then output • How your laptop works,
essentially. But is this how the mind works?
http://www.elsevier.com/connect/wp-content/uploads/2013/06/Turing-Machine.jpg
Side note: What is a “symbol”? • A symbol is anything that stands
for / represents something else
• This is not a pipe (but it is a symbol of a pipe).
• The digit “2” is a symbol. The quantity two is not.
• A map is a symbol. The actual location is not.
• The word “dog” is a symbol. My dog itself is not a symbol. But this picture of my dog is also a symbol. • Are the symbols “dog” and the
picture of my dog equivalent? Is one less symbolic than the other?
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Artificial Intelligence • What sort of things are symbolic processors and
Turing machines good at? What aren’t they good at?
• Original AI using “Turing style” symbolic processing not successful at many “human” tasks. Modern AI works a bit differently, and has had more success.
• Two forms of artificial intelligence • Weak AI – what we currently have – AI that can do
human-like tasks, such as object recognition, driving, or speech processing. Built for one specific task.
• Strong AI – what we do not currently have – AI that is indistinguishable from a human mind and can do all that humans can do to (at least) the same ability as a human.
• What differences exist between modern weak AI and human intelligence?
How can we know that an artificial intelligence has “mind” in the same way
that we do?
• If there were machines bearing the image of our bodies, and capable of imitating our actions as far as it is [practically] possible, there would still remain two most certain tests whereby to know that they were not therefore, really men. Of these the first is that they could never use words or other signs arranged in such a manner as is competent in us in order to declare our thoughts to others . . . so as appositely to reply to what is said in its presence. The second test is . . . to act in all the contingencies of life in the way in which our reason makes us act.
- Descartes
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The Turing Test
The Turing Test
• Is passing the Turing test enough to consider a computer intelligent?
• Is it enough to consider the computer conscious?
• Can a computer have the same mental experience as a human?
http://ichef.bbci.co.uk/news/660/media/images/75395000/jpg/_75395401_eugene-goostman-600x338.jpg
Standard Cognitive Science
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Computational Theory of the Mind • Implied from Turing – the brain is a symbolic
processor
• Perception cues symbolic representation, which can be operated on (processed) mentally to provide the desired output.
• Sensation -> Perception -> Symbolic Representation -> Action Planning -> Action
Standard Cognitive Research
• Most standard cog research follows these basic principles: • Design an experiment that
isolates one cognitive process • Manipulate something
between groups • Measure something and see
if there is a group difference using frequentist statistics
• Use the results to support / refute theories
Standard Cognitive Research
• Assumptions: • Cognition in the lab is roughly equivalent to cognition in
the world (it’s ecologically valid) • The way people do the task is equivalent
• The environment and state of their body (sitting in front of a computer) don’t impact cognition to a meaningful degree
• Cognitive processes can be isolated (e.g., visual search does not require any linguistic abilities) • This is also called modularity, as in two processes are
“modular” and are distinct in the brain
• Differences in mean DV values across conditions (as determined by significant p-values) means the two underlying processes are, in some way, different • And this difference is not due to something like task demands
or subject bias
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Standard Cognitive Research
• As an example, let’s look at some word priming research. • Participants read words off of a
computer screen
• IV – either the first letter is primed or not (using some sort of priming method, whatever kind)
• DV – reaction time (how long it takes to start reading the word)
• Results – participants are faster at reading words when the first letter has been primed
_____ b____
beach beach
Longer RT Shorter RT
Standard Cognitive Research • How do we explain this data?
• Levelt (1999) • The process of speaking a word has multiple “stages”
• One stage is phonetic encoding, a serial process
• When you prime the first letter, it can be phonetically encoded before the rest • This means that the primed letter cues a representation of that
letter to be slotted in to the representational frame of the to be spoken word
• Essentially, how a computer would do this. Symbol manipulation.
• When the rest of the word is presented, you don’t have to phonetically encode the first letter (it’s already there) so…
• Therefore, you see a reduction in RT for primed words!
Standard Cognitive Research • Is this the only explanation?
• From a computationalism point of view, this feels like it tells the whole story. The data is explained in a well- defined theory • This model is also explicitly
computational and can be programmed using algorithmic programming – WEAVER++ model
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Standard Cognitive Research • Thus, aside from providing the
input and producing the output, perception and action do not play a meaningful role in cognition. • Standard cognitive science typically
follows this pattern • “Envatted” brain
• But would it be possible to explain this data WITHOUT the symbolic representation?
• Could we appeal to sensorimotor processes to explain the RT difference instead of appealing to symbolic representation?
• We will come back to this later.
What would cognition entwined with perception
and action look like?
Imagery and Thought • Does thought occur
completely separately from perception?
• Let’s take imagination (a form of thought)
• Imagine the following situation…
• Imagination relies on the visual system and mental imagery. • Eye movements during
imagery • Much more to come here
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Memory in the World
• Suppose our question at hand is “How do people remember lists of items?” like a shopping list.
• Standard cognitive science • Give people lists of items to
remember, have them recall them from memory, determine what factors lead to increased or decreased recall #
• This allows us to build a model of memory, and explain how people remember lists of items…right?
Cognitive Offloading • Now I’ll ask you the same
question… “How do people ACTUALLY remember lists of items?”
• If people offload such tasks on to their environment, where is cognition occurring? Is cognition happening in the environment itself?
• Is cognition localized within the brain? Or is it extended?
• What is and isn’t offloading might be tricky to determine…
Learning Mathematics
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Is this cognition?
An extreme example…?
The Big Question • Standard cognitive science says…
• Perception -> Representation -> Action Planning -> Action • Box and arrow models (like Levelt’s) • Envatted brain
• Alternative paradigms suggest simplifying this, and ditching the problematic notion of “representation” (why? – we will see later) • Perception -> Action -> Perception -> Action ->
Perception….(perception-action loop) • This sort of model has some interesting advantages, and
disadvantages, when compared to standard cognitive science • No symbolic representation = not really a Turing machine • This structure allows for tighter interplay between mind,
body, and environment
• Is the brain a symbolic processor or something else?
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Before we answer (or at least analyze) this question, we will start with the basics of perception. So for now,
keep this in the back of your mind.
Philosophy of Perception
Basic Facts
• We have sensory mechanisms that detect information in the world and transform it into neural signals • Photoreceptors in the eyes • Hair cells in the cochlea
• If we can’t detect it with our sensory mechanisms, we can’t perceive it • Photoreceptors can’t detect IR or UV light • Hair cells can’t detect really high frequency noise
• Therefore, perception utilizes the limited information we get from sensation
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Realism (Direct Perception)
• Naïve realism – we perceive reality as it truly is
• Direct perception
• There is one true reality, and we all perceive it as such.
• What about perceptual illusions?
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Idealism
• There is no reality, it’s all in our heads!
• Or at the very least, what we believe is reality is solely a construction of our minds.
• Therefore, different people occupy vastly different realities.
• Unfalsifiable. So forget it
Middle Ground – Active Construction • There IS a true reality that we all
occupy, however…
• Our perception of reality is actively constructed by our brains based on limited sensory information.
• As these limitations are the same (or very similar) for humans, we have similar (though not necessarily identical!) perceptual experiences.
• Indirect Perception
• Subjective vs. Arbitrary Perception
• Perception = Sensation + Experience
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Bottom-up and Top-Down Processing • Bottom-up processing
• Sensory information builds up to a percept
• Top-down processing • Prior knowledge
disambiguates/molds sensory information
• Directs attention
• Both work simultaneously to determine perception
It’s a cow
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“You will never un-see me!” “Oh and hello again if you’ve seen me before…I’m back!”
With this view comes a slight problem… • If I perceive a replication
(or representation) of reality constructed by my mind, who’s to say my reality and your reality are identical?
• Were the people who knew about the cow living in a different reality when they saw it compared to those who didn’t?
• If not, what was different?
Are my colors your colors?
Chris It’s a normal banana!
I’ve learned that this color is called “yellow”
Joel It’s a normal banana!
I’ve learned that this color is called “yellow”
What color is this banana?
“Yellow” “Yellow”
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Qualia
• The subjective experience of perception is known as qualia • In the previous example, Chris and Lee have different
qualia for the same object, but they don’t know this
• While language can be used to communicate many things, we cannot communicate qualia directly • Contents of conscious experience • We can share language – we can’t share qualia
• Is it possible to know if all our qualia are the same? • Why might this be the case? • Why might this not be the case?
Guiding philosophy – for now
• What we perceive is an accurate reflection of reality
• Perception = Sensation + Experience
• Perception can be subjective, but is not arbitrary
• There is no a priori reason to assume qualia are different between people in the absence of physical difference (e.g., colorblindness)
So what is Perception? • Perception…
• Allows us to effectively act in the world and evaluate the consequences of those actions
• Provides information about the current state of the world, synthesizing with prior knowledge to allow for moment-to-moment prediction
• Dominates our conscious experience
• Is separate from cognition? Is utilized by cognition?
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Perception and Cognition
• Perception • Process of becoming aware of our environment through
sensory organs
• Cognition • Thinking about, operating on, and describing the world
• Language, decision making, memory, problem solving, imagination, navigation
• Can we have perception without cognition?
• Can we have cognition without perception?
• Does cognition utilize perceptual mechanisms? Does cognition RELY ON perceptual mechanisms?
