Chapter 4: Sensation, Attention, and Perception

Transduction

-is conversion

-It refers to the process of converting sensory information into neural signals

Psychophysics

The science of establishing quantitative and measurable relationships between physical stimulation and psychological events

Absolute Threshold 

The lowest level of sensory strength necessary for detection

Ex: hearing a watch ticking 20 ft away

Difference Threshold

• The minimum amount of change in a stimulus that an individual can detect

• AKA the “Just noticeable difference.”

-Ex: changing coca cola bottle (new logo)

-Ex: reducing the size of the chocolate bar so that the company can earn more money

Transduction: Selection and Limitation

Data selection system

Which information to code and send to the brain

Lack of specific transducers

total loss of some sensations like color blindness, hearing loss, sense disorders, etc

Restricted range of transducers

damaged or partially functioning of senses

Sensory adaptation

Sensory receptors become less responsive to constant stimuli over time

ex: unaware of how bad your house smells like

ex: ignoring the a/c sound

Feature detection

allows selective detection of edges, shapes, colors, movement, and more

add an ex

Vision- An Overview

The eyes transduce only a tiny fraction of the range of electromagnetic energies, called the visual spectrum

Basic Anatomy of the Eye

Cornea

Frontmost clear window of the eye; bends light inward to help focus

Lens

Located behind the pupil; adjusts curvature to focus light on the retina

Optic Nerve

The cranial nerve that transmits visual information from the eye to the brain

Photoreceptors

-This is where the Transduction occurs:

-convert light energy into electrical signals that the optical nerve can send to the brain 

Cones

Produce color sensations and fine details

Rods

Cannot detect color, but more sensitive to light than cones - dark adaptation

Limitations of Our Sight

• Limited Visual Spectrum

• Eyesight worsens with age

• Eye Conditions

• Reliant on attention and focus

• Pattern-seeking bias

• Vulnerability to deception and misperception (optical illusions)