textbook

chapter 1

  • perception - conscious sensory experience

    • the experiences that result from stimulation of the senses

      • something we usually accomplish so easily that we often don’t even give it a second though

1.1 Why read this book?

  • provides info that may be helpful in other courses and even in your future career

  • relevant to future studies in medicine and related fields

  • studying perception can help you become more aware of the nature of your own perceptual experiences

1.2 Why is this book titled Sensation and Perception?

  • sensation - often identified with elementary processes that occur at the beginning of a sensory system

    • ex. when light reaches the eye, sound waves enter the ear, food touches your tongue

    • involves detecting elementary properties of a stimulus

  • perception - identified with complex processes that involve higher-order mechanisms such as interpretation and memory that involve activity in the brain

    • involves the higher brain functions involved in interpreting events and objects

  • sensation was discussed in the early history of perceptual psychology

    • researchers eventually stopped using the term sensation

  • now, everything that involves understanding how we experience the world through our senses comes under the heading of perception

1.3 The Perceptual Process

  • a sequence of steps leading from the environment to perception of a stimulus, recognition of the stimulus, and action with regard to the stimulus

  • process begins with a stimulus in the environment and ends with the conscious experiences of perceiving the tree, recognizing the tree, and taking action with respect to the tree

  • summarizes the major events that occur between the time a person looks at the stimulus in the environment and perceives the tree, recognizes it, and takes action toward it

Distal and Proximal Stimuli (steps 1 and 2)

  • distal stimulus (step 1)

    • the stimulus “out there,” in the external environment

    • the tree that the person is observing

  • proximal stimulus (step 2)

    • the stimulus on the receptors

      • in vision, this would be the image on the retina

    • its in proximity to the receptors

    • representation of the tree on the receptors

  • the principle of transformation

    • states that stimuli and responses created by stimuli are transformed, or changed, between the distal stimulus and perception

  • the principle of representation

    • states that everything a person perceives is based not on direct contact with stimuli but on representations of stimuli that are formed on the receptors and the resulting activity in the person’s nervous system

  • both steps illustrate transformation and representation

    • distal stimulus (tree) is transformed into the proximal stimulus

    • the image represents the tree in the person’s eyes

Receptor Processes (step 3)

  • sensory receptors

    • cells specialized to respond to environmental energy, with each sensory system’s receptors specialized to respond to a specific type of energy

    • visual receptors respond to light

    • auditory receptors respond to pressure changes in the air

    • touch receptors respond to pressure transmitted through the skin

    • smell and taste receptors respond to chemicals entering the nose and mouth

    • when sensory receptors receive the information from the environment, they do two things:

      • transform environmental energy into electrical energy

      • shape perception by the way they respond to different properties of the stimuli

  • transduction

    • the transformation of environmental energy to electrical energy

    • this allows your sensory receptors information that is out there

Neural Processing (step 4)

  • once transduction occurs, the tree becomes represented by electrical signals in thousands of sensory receptors

  • what happens to these signals?

    • they travel through a vast interconnected network of neurons that

      1. transmit signals from the receptors to the brain and then within the brains; and

      2. change (or process) these signals as they are transmitted

    • these changes occur because of interactions between neurons as the signals travel from the receptors to the brain

  • neural processing

    • operations that transform electrical signals within a network of neurons or that transform the response of individual neurons

    • the changes in these signals that occur as they are transmitted through the maze of neurons

  • primary receiving area

    • area of the cerebral cortex that first receives most of the signals initiated by a sense’s receptors

  • cerebral cortex

    • a 2-mm-thick layer that contains the machinery for creating perceptions, as well as other functions, such as language, memory, emotions, and thinking

  • occipital lobe

    • primary receiving area for vision

    • a lobe at the back of the cortex that is the site of the cortical receiving area for vision

  • temporal lobe

    • the area for hearing

    • a lobe on the side of the cortex

  • parietal lobe

    • the area for the skin senses - touch, temperature, and pain

    • a lobe at the top of the cortex

  • frontal lobe

    • receives signals from all of the senses

    • plays an important role in perceptions that involve the coordination of information received through two or more senses

Behavioural Responses (steps 5-7)

  • electrical signals have been transformed into the conscious experience of perception, which then leads to recognition

  • perception - conscious awareness of the tree

  • recognition - placing an object in a category

  • visual object agnosia - inability to recognize objected

Knowledge

  • any information that the perceiver brings to a situation, such as prior experience or expectations

  • bottom-up processing (data-based processing)

    • processing that is based on the stimuli reaching the receptors

  • top-down processing (knowledge-based processing)

    • processing based on knowledge

1.4 Studying the Perceptual Process

  • stimulus (distal and proximal; steps 1-2)

  • physiology (receptors and neural processing; steps 3-4)

  • behaviour (perception, recognition, action; steps 5-7)

  • oblique effect

    • people see vertical or horizontal lines better than lines oriented obliquely

The Stimulus-Behaviour Relationship (A)

  • relates stimuli to behavioural responses, such as perception, recognition, and action

  • psychophysics

    • measures the relationships between the physical (the stimulus) and the psychology (behavioral response)

  • grating acuity

    • the narrowest spacing of a grooved surface on the skin for which orientation can be accurately judged

The Stimulus-Physiology Relationship (B)

  • the relationship between stimuli (steps 1-2) and physiological responses, like neurons firing (3-4)

  • often studied by measuring brain activity

The Physiology-Behaviour Relationship (C)

  • relates physiological responses (steps 3-4) and behavioural responses (steps 5-7)

Measuring Perception

  • absolute threshold

    • the smallest stimulus level that can just be detected

  • thresholds

    • measure the limits of sensory systems

    • measures of minimums - the smallest line-width that can be detected, the smallest concentration of a chemical we can taste or smell, the smallest amount of sound energy we can hear

Measuring Thresholds

  • classical psychophysical methods

    • the methods of limits, adjustment, and constant stimuli, described by Fechner, that are used for measuring thresholds

  • method of constant stimuli

    • similar to the method of limits in that different stimulus intensities are presented one at a time, and the participant must respond whether they perceive it on each trial

    • difference is that the stimulus intensities are presented in random order, rather than in descending or ascending order

  • method of adjustment

    • adjusts the stimulus intensity continuously until he or she can just barely detect the stimulus

  • difference threshold

    • the minimum difference that must exist between two stimuli before we can tell the difference between them

Measuring Perception Above Threshold

5 questions about the perceptual world and the techniques used to answer these questions

question 1: what is the perceptual magnitude of a stimulus

  • technique: magnitude estimation

    • a psychophysical method in which the subject assigns numbers to a stimulus that are proportional to the subjective magnitude of the stimulus

  1. Perceptual Magnitude of a Stimulus:

    • Technique: Magnitude Estimation

    • Description: Participants assign numerical values to stimuli based on perceived intensity compared to a standard stimulus.

  2. What is the Identity of the Stimulus:

    • Technique: Recognition Testing

    • Description: Participants categorize and name objects or stimuli, used to assess recognition abilities, especially in individuals with brain damage.

  3. how quickly can i react too it:

    • Technique: Reaction Time Measurement

    • Description: Measures the time between stimulus presentation and the participant's response, indicating how quickly they can react.

  4. how can i describe what is out there:

    • Technique: Phenomenological Report

    • Description: method of determining the relationship between stimuli and perception in which the observer describes what he or she perceives

  5. how can i interact with it:

    • Technique: Physical Tasks and Judgments

    • Description: Participants perform tasks or make judgments involving perception and action, such as reaching for objects or navigating spaces.

why is the difference between physical and perceptual important?

chapter 2

chapter 3

chapter 4

chapter 5

chapter 6

chapter 7

chapter 8

chapter 9

chapter 10

chapter 11

chapter 12

chapter 14

chapter 15