Name and state the stages of stimuli processing (7)

seven stages of stimuli processing  and the  stages are: steps 1&2: Stimuli, Step 3: Processes & Transduction, Step 4 neural proccessing and steps 5-7: behavioural responses

step 1 & 2 Stimuli

Principal of transformation

transformation from the stimulus to electromagnetic energy (light) to electrical signals (neural firing)

Principle of representation: states that everything a person perceives is based on representations of stimuli that are formed on the receptors and on activity in the person’s nervous system

Step 3: Processes & Transduction

Sensory receptors are specialized to respond to environmental stimulus

Transduction  changes environmental energy to nerve impulses

primarily a change or transduction from electromagnetic radiation in visual systems to electrical impulses

Sensory receptors are specialized to respond to environmental stimulus

Stage 4: Neural Processing

Neural processing is the changes that occur as signals are transmitted through the maze of neurons

Primary receiving areas are: Occipital Lobe Temporal lobe Parietal Lobe

Steps 5-7: Behavioral Responses

Experience and action

Perception occurs as a conscious experience

Recognition occurs when an object is placed in a category giving it meaning

Action occurs when the perceiver initiates motor activity in response to recognition

What is knowledge and what are the two ways it’s processed?

Knowledge is any information a perceiver brings to the situation.

Bottom-up processing Also known as data-based processing. Processing is based on incoming stimuli from the environment

Top-Down processing Also known as knowledge-based processing Processing based on the perceiver’s previous knowledge Prior exposure will bias perception/interpretation

When does an afterimage become visible

when one given hue stays on the same retinal position for several seconds  Afterimage builds up as the retinal location adapts to the special hue and when looking at  a neutral background the complimentary color is seen

state and define the two behavioral approaches to perception

psychophysical methods (Detection/Discrimination)

Magnitude Estimation (Perceiving magnitude)

Psychophysics was Gustav Fechner and  Is the study of the relation between the physical stimulus and our perception of that stimulus

Magnitude estimation was Develop by S.S Stevens and relates perceived magnitude and stimulus intensity

Methods of psychophysics are:

Method of adjustment, limits and constant stimuli

Method of adjustment

Observer adjusts the stimulus intensity until the stimulus is detectable

Several settings

Settings are averaged to provide an estimate of threshold

Fast and easy for the observer to perform

Open to bias (observer controls the stimulus intensity and know what is being measured)

Method of limits

Observer is passively watching the stimulus with experimenter controlling the presentation of stimulus intensity

Stimulus is presented in an alternating ascending or descending sequence Starting point varies

Crossover points between yes and no response are averaged to determine threshold

Open to expectation bias and more time consuming

Method of constant stimuli

Range of test values around what you think the threshold will be

Present each one in random order

Plot the psychometric function, point of 50% observed

Very precise

requires more time and prior knowledge about observer performance

Method of adjustment experiment used to determine range of test values prior to constant stimuli experiment+

Describe the method used in magnitude estimation

Standard stimulus is presented

Subject assigns a value to that stimulus

All subsequent stimuli are rated relative to the standard

Average rating for each intensity is taken

What is steven’s power law and what is its purpose?

P(perceived magnitude)=K(constant)*S(Stimulus)^N.

Mathematically express or Describe relationships of magnitudes

What orientations are people best at discriminating?

People are better able to discriminate vertical and horizontal changes in orientation

What Is an Absolute Threshold?

Absolute threshold is the smallest amount of energy needed to detect a stimulus

determined by the point at which observers respond 50% of the time that they have perceived the object

What is another name for a difference threshhold?

Just noticeable difference is the smallest difference between two stimuli that a person can just detect

 JND=S(Stimulus)*K(Constant). JND/S=K

define Response expansion and compression

Response compression is a small change in intensity results in a big perceived changed then as intensity increases, responsiveness flattens

Response expansion is a slow increase in perception with increasing intensity followed by sharp rise  in perception with little change in intensity