Cognitive Psychology

What is cognitive psychology?

A branch of psychology concerned with the scientific study of the mind - that includes such mental processes as perception, attention, memory, language, problem solving, etc.

How is it possible to study the inner workings of the mind, when we can't really see the mind directly?

We can study cognition indirectly by observing and measuring behavior.

Donders' reaction time experiment

Simple reaction time

-When light flashes, push button

Choice reaction time

-When light flashes on left or right, push left or right button.

Average Choice RT 250 ms

- Average Simple RT 150 ms

= 100 ms to make a decision

Ebbinghaus' memory experiment

Present a list of nonsense words:

DAX

BIV

LUH

etc.

Recorded number of trials to learn the list initially

After a delay, recorded how many repetitions it took to relearn list - this was then converted into percent savings

Wundt's psychology laboratory (1879)

Used introspection to study the mind.

Introspection - technique of breaking down psychology experiences into primary sensations.

Behaviorism (John Watson)

A movement in psychology that emphasized the study of behavior over inner mental processes.

Watson believed that psychology's goals should be to predict and control behavior and not study the inner workings of the mind.

Watson's Little Albert Experiment

-Showed certain behaviors can be socially taught and modeled

Operant conditioning

Focuses on how behavior is strengthened by the presence of positive reinforcement.

Tolman's cognitive map

Mental representation which serves an individual to acquire, code, store, recall, and decode information about the relative locations in their everyday or metaphorical spatial environment

Skinner on Language Acquisition

In Verbal Behavior Skinner asserted that children learn language through operant conditioning.

Child sees a dog, says "Doggie!" Parents say, "Right, that's a doggie!" Child's verbal behavior reinforced by parents.

Chomsky on Language Acquisition

Chomsky attacked Skinner's "Verbal Behavior"

Said humans are born with the knowledge of how to acquire and use language.

Chomsky's pointed out that children say things that they've never heard before or been reinforced for before like, "I hitted the ball" or "I sawed the kitty" or "I hate you Mommy!"

Chomsky believed that language emerges through an inborn biological program.

Information-Processing Approach

Cognitive neuroscience

The study of the physiological basis of cognition.

Physiological means the internal workings of the body.

Basic structure of a neuron

Neuron = individual cell of the brain

Action potential

Brief electrical charge that travels down the axon

Electrical impulse, All-or-nothing, Intensity is always the same.

Rate of Firing

The intensity of action potentials is always the same but the rate of firing changes how strong the signal is.

How neurons communicate

Neurons transmit information both electrically (action potentials) and chemically (neurotransmitters).

Neurons do not function in isolation. They are organized into groups or neural circuits which process specific kinds of information.

Localization of function

Specific functions are served by specific areas of the brain.

Modularity

The idea that the brain is composed of innately specified structures (modules) that perform very specific functions.

Early ideas about localization of function

Phrenology, developed by Franz Joseph Gall in 1796, is the idea that certain areas of the brain have specific functions and that personality can be determined by bumps on the skull.

Although phrenology is a pseudoscience, it did contribute to the development of neurology and the idea of localization of function.

Primary receiving areas

Different brain lobes play larger roles in perceiving certain sensory

Vision - occipital

Hearing - temporal

Touch - parietal

Fusiform face area (FFA)

A part of the human visual system that, it is speculated, is specialized for facial recognition, although there is some evidence that it also processes categorical information about other objects, in particular familiar ones.

Prosopagnosia

Inability to recognize faces

Localization of motor function

Higher-order cognition (planning, language, attention, problem solving, personality, etc.) - frontal lobe

Phineas Gage

Foreman of a railroad construction company in Vermont. One day an explosion caused a 3 1/2 ft. tamping iron to shoot through Phineas' head.

It was thought that most of the left side of his prefrontal lobe was destroyed.

Phineas' was the first case suggesting that damage to the prefrontal lobe could affect personality and behavior.

Evidence of localization of language function - Broca's

In 1865 French physician Paul Broca was introduced to a man who couldn't produce fluent speech after a stroke. He was only able to say a few sounds, including the word "tan".

After the man died, Broca examined his brain and found that he had damage to an area of his left frontal lobe.

This area was named Broca's area and was thought to control the production of speech.

Wernicke's area

Carl Wernicke discovered that damage to an area in the left temporal lobe above the ear caused the inability to understand spoken words.

This area was called Wernicke's area and was thought to be involved in language comprehension.

People with damage to Wernicke's area can produce speech, but it often makes no sense (sometimes called "word salad"), and they often can't understand what is being said to them.

Aphasia

Language impairment due to brain damage

Broca's aphasia - impaired speech production

Wernicke's aphasia - impaired language comprehension

Broca's Area - Production vs. Syntax

New research suggests that Broca's aphasia not just a problem with production but also a problem with form (syntax):

The apple was eaten by the girl. (no problem)

The boy was pushed by the girl. (problem)

Broca's have no problem understanding the first but have problem with second sentence.

B/c have to know who pushed whom. Have to know syntax.

Therefore, Broca's aphasia is a problem with form (syntax) and Wernicke's a problem with meaning.

Brain Hemispheres: Localization of Function

Left hemisphere is better at analysis and calculation.

The right hemisphere is better at perceptual tasks, such as pattern recognition and spatial relations. It is also better at making inferences, processing emotion, and facial recognition.

Testing Hemispheric Differences (long paragraphs)

Researchers have found that if they control the information that goes to one-half of the split-brain patient's brain, they get interesting behaviors that reveal things about the functions of the two hemispheres.

If a word is flashed quickly on the right side of a computer screen, the information goes only to the patient's left hemisphere. Normally, this information gets sent to the right hemisphere immediately by the corpus callosum, but in split-brain patients, this information is not shared.

However, if the word is flashed on the left side, the patient can't say what he saw, because the information goes to the right hemisphere and the right hemisphere doesn't have access to language.

However, he is able to draw a picture of what he saw with his left hand, even if he isn't consciously aware of having seen it, because he is drawing with his right hemisphere.

What does visual tests show us about hemispheric specialization

Messages are sent between hemispheres in the corpus collosum.

Things seen on the left side are sent to the right hemisphere and vice versa (only w/ corpus collosum)

When someone w/o a CC sees something on the left, they can't say what they see because the right side doesn't have access to language.

HOWEVER - The person was able to see the image on the left and draw it, then when they didn't recognize what it was

Distributed processing

Specific functions are processed by many different areas of the brain.

Cognition is the result of many specialized brain areas (localization) working together to create a distributed pattern of activity across the brain (distributed processing).

Representation

How objects are characterized in the brain.

A representation is something that stands for something else.

Our perception of things we see is based not on direct contact with the tree, but on the way the tree is represented by action potentials in the brain.

Grandmother cell

Grandmother cell is a single neuron that only responds to a specific stimulus.

We used to think there was a "grandmother cell" for every object.

The problem with the grandmother cell idea is that there are too many objects in the world to be represented by just one neuron, and every neuron responds to more than one object.

Neural code

Every object is represented by a particular pattern of firing in a number of neurons.

Each object has it's own unique neural "chorus" of firing.

These patterns of neural firing are the neural code for a particular stimulus.

This is the idea of distributed coding.

Distributed Coding vs. Processing

Distributed coding is different from distributed processing in that distributed coding refers to the pattern of firing of a number of individual neurons, and distributed processing refers to the activation of a number of different areas of the brain.

Brain Imaging: EEG and ERP

Measure electrical activity of the neurons across the brain.

Used to diagnose epilepsy, sleep disorders, coma, or brain death.

Temporally precise but hard to locate exactly where the signals originate.

Brain Imaging: PET scans

Use a radioactive form of glucose to identify activity in the brain.

Brain Imaging: MRI

(Magnetic Resonance Imaging) is another brain imaging technique, but it doesn't involve radiation. It allows us to see the structure of the brain using magnets.

Brain Imaging: fMRI

Another brain imaging technique is fMRI or function magnetic resonance imaging. Like the PET scan it takes advantage of the fact that more blood flows to areas of the brain that are the most active.

How do we know which areas of most active?

Subtraction technique: determines the areas that are most active during stimulation by subtracting control activity from stimulation activity.