FIRST QUIZ

Cognitive Psychology

Study of mental processes ( or cognition) using the scientific method

Cognition involves

* Perception
* Attention'
* Memory
* Knowledge representation
* Language
* Problem-Solving
* Reasoning and decision-making

Characterization

Observing or measuring a phenomenon

Hypotheses

Theoretical explanation of the obervations

Predictions

Reasoning based on hypotheses

Experiments

1. Independent Variables
2. Dependent Variables

Independent Variables

What is being manipulated by the experimenter

Dependent variables

What is being measured

Donders’

(1868) Earliest person to be recognized for work in Cognition

* Subtractive Method
* Mental Chronometry
* Reaction Time (RT) Experiment

Mental Chronometry

Measuring how long a cognitive process takes

Reaction time (RT) experiment

Measures interval between stimulus presentation and he participants response to a stimulus

What did Donders conclude from his experiment?

It takes 100msecs to make a decisions

How did Donders complete his RT experiments?

Used a Phonautograph and a tuning fork

Wundt (1879)

* First Psychology Laboratory
* University of Leipzig, Germany

Wundt (1879) Approach

Structuralism: experience is determined by combining elements of experience called sensations

Wundt Method

Analytic introspection: participants trained to describe experiences and thought processes in response to stimuli

Ebbinghaus (1885)

– Read list of nonsense syllables aloud many times to determine number of repetitions necessary to repeat list without errors

– After some time, he relearned the list

• Short intervals = fewer repetitions to relearn

– Learned many different lists at many different retention intervals

\-- Forgetting Curve

Savings=

(initial repetitions) – (relearning repetitions)

William James (1890)

Taught first psychology course at Harvard University

Wrote the “ Principles of Psychology”

“Principles of Psychology” (1890)

• Made important and insightful observations about the mind

• However, James did not run experiments

• All observations were based on his own introspection

John Watson

Noted problems with introspective approaches:

* Extremely variable results from person to person
* Results difficult to verify
* Invisible inner mental processes

Who proposed a new approach call Behaviorism?

John Watson

What is Behaviorism?

* Eliminates the mind as a topic of study
* Instead, Study directly observable behavior

What is the Little Albert Experiment

* Performed by Watson (1920)
* Classical Conditioning of fear
* 9 month old became scared of a bunny or a rat

Classical Conditioning

• Pair a neutral event with an event that naturally produces some outcome

• After many pairings, the “neutral” event now also produces the outcome

What was learned from the Little albert experiment

* Behavior can be analyzed without any reference to the mind
* Examined how pairing one stimulus with another affected behavior

Skinner ( 1950)

* Interested in determining the relationship between stimuli and responses


* Operant conditioning
* Pigeons and the Crib

Operant Conditioning

* Shape behavior by rewards or punishments
* Behavior that is rewarded is more likely to be repeated
* Behavior that is punished is less likely to be repeated

What was the controversy over language acquisition?

Skinner dinner

* Argued that children learn language through operant conditioning
* Children imitate speech they hear
* Correct speech is rewarded

Chomsky Language argument:

Argued children do not only learn language through imitation and reinforcement

* Children say things they have never heard and cannot be imitating
* Children say things that are incorrect and have not been rewarded for

Language must be determined by innate biological programs

Tolman (1938)

Trained rats to find food in a four-armed maze

Two competing interpretations:

* Behaviorism predicts that the rats learned to “turn right to find food”
* Tolman believed that the rats had created a cognitive map of the maze and were navigating to a specific arm

The Cognitive Revolution

Shift from the behaviorist stimulus-response relationships to an approach that attempts to explain behavior in terms of the mind

Structural Models

Representations of a physical structure, mimic the form or appearance of a given object

Process Models

Represent the Processes that are involved in cognitive mechanism, with boxes usually representing specific processes and arrows indicating connections between the processes.

What is Neuroscience

Scientific study of the nervous system

What is Cognitive Neuroscience?

Study of the relation between the nervous system and cognition

Neurons

Cells specialized to receive and transmit information in the nervous system.

Cell body

contains mechanisms to keep cell alive

Axon

Tube filled with fluid that transmits electrical signal ( towards other neurons)

Dendrites

Multiple branches reaching from the cell body which receive information from other neurons

Measuring action potentials

Size remains mostly constant

Rate of firing that is measured

Low intensity input : ---- firing

Slow

High intensity input: ----- Firing

fast

Synapse

space between the axon of one neuron and a dendrite from another neurons

What happens when the AP reaches the end of a neuron?

synaptic vesicles open and release chemical neurotransmitters

What are neurotransmitters?

Chemicals that affect the electrical signal of the post synaptic neuron

What are excitatory Neurotransmitters?

They increase the likelihood that the post synaptic neuron will produce a spike ( Glutamate)

What are Inhibitory neurotransmitters

decreases the likelihood that the post synaptic neuron will produce a spike (GABA)

An action potential only results if it reaches the?

Threshold

What processes the number ad timing of impulses received?

Cell membrane

What are Feature detectors?

Neurons that respond best to specific stimulus

What did Hubel and Wiesel propose in (1965)

Simple vs complex cells

Simple Cells

Neurons that respond best to bars of light of a particular orientation

Complex cell

Neurons that respond best to an oriented bar of light with a specific length

Specificity coding

representation of a specific stimulus by firing of specifically tuned neurons specialized to just respond to a specific stimulus

Distributed coding

Representation by a pattern of firing across a large number of neurons

Sparse Coding

Distributed representations using a small number of neurons ( this is the likely solution)

What is localization of function?

* Idea that specific functions are served by specific areas of the brain

Method: Lesion

* One of the oldest methods to localize functions
* Lesions in humans need to be accidental, animals are easier to study because you can cause damage

Transcranial Magnetic stimulation

\-Safely reproduce the effect of a temporary cortical lesion

\-Temporarily add noise to neural activation (rTMS).

* Limited to cortical regions

Method: Inactivation

* with non-human animals
* muscimol is a gaba agonist, so we use it to inactivate brain structures with Gaba receptors

Method: Brain Imaging

Lot of different Brain imaging tech

Positron Emission tomography (PET scan)

* Blood Flow increases in areas of the brain recruited by a cognitive task
* A radioactive tracer is injected into the blood stream, and it measures the signal from tracer at each location of the brain.
* Higher signals indicate higher levels of brain activity’s

What is the subtraction technique

* measures brain activity before and during stimulation presentation
* Difference between activation determines what areas of the brain are active during the manipulation

Functional Magnetic Resonance Imaging (fMRI)

* Uses Subtraction technique
* Measures blood flow through magnetic properties of blood
* Advantage: no radioactive tracer

Electroencephalography (EEG)

* Neuron firing is an electrical event
* EEG measures electrical **activity** on the scalp to make inferences about underlying brain activity
* Used to calculate event-related potentials( ERPS)
* Advantages: Continuous and rapid measurements
* Disadvantages: Does not give precise location

Frontal Lobe

* Reasoning and planning
* Language, thought, memory, motor functioning

Parietal Lobe

* visual attention
* Touch, temperature, pain, and pressure

Temporal Lobe

* Auditory and perceptual processing
* Language, hearing, memory, perceiving forms

Occipital

Visual Processing

Basal Ganglia

Categorization and sequence processing

Hippocampus

Forming memories

Amygdala

Emotions and emotional memories

Thalamus

Relaying information from vision, hearing, and touch senses

McCabe and Castel (2008)

Seeing is believing: The effect of brain images on judgment of scientific reasoning

what did Weisberg and McCabe and Castel both suggest?

that explanations of psychological phenomena appear better if they are accompanied by neuroscience

Perception

The process of recognizing, organizing and interpreting information from senses

Inverse Projection Problem

* Refers to the task of determining the object responsible for particular image on the retina
* involves starting with the retinal image and then extending outward to the source of that image

Viewpoint invariance

Objects look different from different viewpoints

Bottom-up processing

* Perception starts with the senses
* Incoming raw data
* Energy registering on receptors

Top-Down Processing

* Perception starts with the brain
* Person’s knowledge, experience, exectations

Direct Perception theories

* Focus in bottom-up processing
* Perception comes from stimuli in the environment
* Parts are identified and put together and then recognition occurs

Constructive perception theories

* Focus on top-down processing
* People actively construct perceptions using information based on expectations

Template matching

Parsimony: one template per separate letter/object

* No neurological support
* Can they account for variability?

Pandemonium ( Selfridege)

* Data-Driven ( bottom up) recognition model
* Based on feature analysis
* objects recognized from analysis of their components
* Composed of 4 types of recognition units ( demons)

1. Image Demons

* Record initial image of external signal
* Retina Receptors + sensory memory

2. Feature demons

* Look for a particular characteristic in the pattern
* Specific line
* Specific angle
* Simple cells + Feature detectors

3. Cognitive demons

* They watch the responses of the feature demons and seek out one particular pattern
* Working memory ( Retrieves from long-term memory)

4. The decision demon

* Listens to the pandemonium created by the demons
* Answer determined by the demon that is yelling the loudest

Arguments in favor of pandemonium

* Power
* Flexibility
* Neurological support
* Hubel and Wiesel

recognition by components theory

* Bottom-up/Featural approach
* Object recognition
* 2D representational building block set
* of 3D features
* Object recognition by separation into 36 geons
* Connection at vertices

Geons

* How theyre made
* Basic 3D shapes

Advantages for geons

* Power
* Flexibility

Shortcoming of bottom-up processing

Does not account for “context” effects and expectations

Top-down Processing (Constructive Perspective)

Top-down processing involves making inferences based on context, guessing from experience, and basing one perception on another

Perceiving size

* Perceived size is a function of both bottom-up and top-down processing
* Bottom- up processing
* the size of the image on the retina
* Top-down processing
* The perceived distance of the object
* The size of the object relative to other objects in the environment

Law of good continuation

Lines tend to be seen as following the smoothest path

Law of good figure ( simplicity or pragnanz)

Every stimulus pattern is seen so the resulting structure is as simple as possible

Law of Similarity

Similar things appear grouped together