CognitionFrom Sensory Perception to Memory &

Learning

Sensation & Perception• Different modes of interaction are

processed in parallel by different sensory systems

• The receptors in each system analyze and deconstruct stimulus information

• Each sensory system then represents this information in specific pathways

• This constant flux of information is edited in a continuum of perceptions

Perception & Cognition• The appearance of perceptions as direct

and precise is an illusion• Perception is the result of a myriad of

connections• Connections can be altered by learning

and activity• The goal of cognitive neural science is

the study of the internal representation of mental events– How we “know” what we know

History of Cognitive Science

•  Hermann Ebbinghaus - 1885– German psychologist– 1 st studies of mental processing – who pioneered in the development of

experimental methods for the measurement of rote learning and memory.

• Ivan Pavlov - 1926– Russian physiologist and experimental

psychologist. – Demonstrated classical conditioning– Demonstrated that specific areas in the

cerebral cortex are concerned with specific reflexes

– Mechanistic theory of human behavior

Pavlov’s Terms• Conditioning or conditional learning

– pairing a neutral stimulus with one that elicits a particular reflex.

• An unconditional stimulus (US) – one that normally elicits the response

• Unconditional response (UR)– The response to the stimulus

• Neutral stimulus (NS)– A stimulus that does not normally produce the

response which can be coupled with the US

• Conditional response– The response normally associated with the US,

now evoked by the NS

The meat is used the US. The bell ringing is the NS

The conditioning process involves presenting the NS & the US at the same time (contiguously) and repeating this many times. The more repetitions, the stronger the conditioning.

Once conditioning has been established, the dog is presented with ringing of the bell without the meat. If the conditional response has been established the ringing bell will elicit salivation almost as if the meat had been presented.

•Edgar Thorndike –Built on Pavlov–quantitative approach

Major Types of Conditioning

• Simultaneous Conditioning – The US (meat) and the CS (bell) are

presented at the same time.

• Delayed Conditioning – The CS is presented before the US (meat). – While the two stimuli are not simultaneous,

there is always some point in time when both are occurring.

• Trace Conditioning – The CS stops before the US is presented.

Behaviorism• J.B. Watson –1925

– focused on observable aspects of behavior (response to controlled stimuli)

– ignored constructive brain processes such as thinking, planning, memory,etc.

– led to behaviorism

• “Give me a dozen healthy infants, well-formed, and my own specified world to bring them up and I'll guarantee to take any one at random and train him to become any type of specialist I might select--doctor, lawyer, merchant-chief, and yes, even beggarman and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors." (1930)

Cognitive Psychology & Neurology

• A response to behaviorism began in the 1960’s

• Perception shapes behavior• Perception itself is a constructive process• It depends not only on the information of

the stimulus, but also the mental structure of the receiver = internal representation

Five Aspects of Cognitive Neural Science

• The activity of single cells• Information processing

– how you get a response

• Behavioral neurology – study of patients with brain lesions

• Imaging techniques – PET, MRI, voltage sensitive dyes

• Computer modeling of neural networks – understanding brain circuitry