Introduction to Cognitive Science pages 1 - 9

Pages 1 - 9

Classical conditioning

Reflex: simple and automatic stimulus-response. Strength decreases due to habituation (weakens stimulus-response). Phenomena (bell) and generalization (similar stimulus).

Pavlov

Father of conditioning, salivation in dogs.

Volkova

Children are conditioned to good and bad

Watson

The creation of simple stimulus-response. Behaviorist, only what is observable.

Behaviorism

Creating a simple stimulus-response connection (sound → salivation)

Cognitivism

Creating stimulus-stimulus connection (sound → mental representation → salivation)

Rescorla (1973) habituation experiment

Rats display freezing response to a loud sound. Pair it with light, then they also react to the light. Habituating half of the group to not respond to the sound anymore. Behaviorists say that the rats will still display response to the light (S-R connection) and cognitivist say the will not (S-S connection)

Operant conditioning

Self-initiated behavior

Thorndike’s puzzle box

Cat needs to find lever to open door and get food

B.F. Skinner

New puzzle box. Animal stays in box and can produce more operant responses

Shaping (operant conditioning)

Training of complex behavior by rewarding successive steps in that behavior

Discrimination (operant conditioning)

Pressing the lever will only give food if the light is on, the light being on is the discriminative stimulus (signal)

Concept learning (operant conditioning)

Discrimination training (only given for certain painting) and generalization (peck on one painting also pecks on others)

Partial reinforcement (operant conditioning)

Continuous (always response), partial (not 1-1 relation, interval-bases) and variable (resistant to extinction) reinforcement

Turing

If something can simulate single tape turing machine it is turing-complete (like humans)

Warren McCulloh and Walter Pitt’s three principles

Basic phsyiologoy, propositional logic and turings theory of computation

Psychophysics

Threshold values. Difference threshold: minimal difference intensity between two stimuli. This is the just noticeable difference (jnd).

Weber’s law

There is a linear relationship between the jnd and the absolute intensity of the stimulus

Cherry

Dichotic listening task

Shadowing

Read back a story form one ear as it arrives (two stories at the same time, one is ignored)

Arguments against early selection

Some information breaks through (Moray 1959), the shadowed story is filled when it is switched ti the other ear (Treisman 1960) and the conditioned fear response in ignored ear (Corteen&Wood 1972)

Alternatives to early selection

Late selection, attenuation and capacity explanation

ELIZA

Natural language processor. Creates illusion of understanding with simple techniques. Weizenbaum did not realize that short exposure could induce powerful delusional thinking.

Kenneth Colby

Modified the Turing test. PARRY simulated paranoid schizophrenia, it gave inconsistent and meaningless sentences

Terry Winograd

SHRDLU has limited world containing colored objects that can be manipulated by a robot arm. Syntactic: parse the sentence and identify nouns. Semantic: assign meaning to individual words. Integration: how information fits into current knowledge

Visual imagery

Thought is possible without image

Spatial or depictive representation

Visual images of your room

Propositional representation

Pizza was on the table

Physical properties of stimuli

Effects of brightness, contrast and speed of motion. High similarity between perceived and imagined stimuli

David Marr

Neuroscientist on visual processing. Three levels for analysing a system: computational level (what problem needs to be solved), algorithmic level (how does it perfom computation) and implementation level (how is the system physically realized)

Steps in recognition

Image projected on retina (perceptual constancy) → invariant representation of object (classification mechanism) → classification of object

Algorithmic level of vision

Primal sketch (light-dark transitions into blobs and edges, finding contours), 2.5-D sketch (view centered, orientation of surfaces) and 3-D sketch (object centered, description of the object)

Constancy

Objects of different size/brightness/shape on the retina can be similar in size in reality (our brain corrects for distance, lightning and orientation and perspective distortion)

Concept

Mental representation of a class. Mutimodel: semantic, visual, auditory and tactile

Categorization by definition

Qualities of a cat (4 legs) with family resemblance, a cat with 3 legs is still a cat

Categorization by prototype

Average idealized representation

Biederman recognition by components

Features are geons (basic shapes), using shapes we can create all objects

Phrenology

Bumps on the skull are indicative of mental abilities

Rene Descartes (1596-1650)

A soul is only for human acts like thinking and believing. The pineal gland was thought to be the place of interaction (Cartesian dualism).

Thomas Hobbes(158-1679)

The soul is a meaningless concept. All behavior is the result of physical processes (materialism). Thought is anchored in the physical world (neural firing)

Frontal lobotomy (20th century)

Removal of the frontal lobe reducing the complexity of psychic life.

Prefontal lobotomy

Only target part of the frontal lobe (transorbital route)

Walter Freeman (1945)

Icepick through the eye socket, negative side effects (cognitive impairments)

Paul Broca (1824-1880)

Clinical neuropsychology. Damage to different brain areas leads to different behavioral impairments

Broca’s area

Damage impairs speech

The brain

Outer part is the cerebral cortex, divided into two hemispheres connected by the corpus callosum. Hempispheres are symmetrical in sensory and motor function but lateralized.

Aphasia

Deficit in speech production or comprehension (stroke or head trauma)

Broca’s aphasia (non-fluent aphasia)

Speech is effortful, non-fluent but meaningful

Wernicke’s aphasia (fluent aphasia)

Speech is fluent but lacks meaning

Corpus callosotomy (split-brain)

The removal of the corpus callosum, can reduce epilepsy

Properties of neglect

Neglect can be limited to the peri-personal space (within arm reach). Affects part of the mental image (visual imagery)

Visual agnosia

Not recognizing visually presented objects without dysfunctions in visual acuity, memory, language and intelligence. Patients recognize objects bases on tactile/auditory information

Form agnosia

Perceive shape

Integrative agnosia

Recognize shape

Case study HJA (integrative agnosia) by Humphreys and Riddoch

Can draw but with effort (robot-like). Can give verbal description of objects shape and elements.