Chapter 4.1 sensation and perception, Chapter 4.2 signal detection theory, chapter 4.3 gestalt principles

Stimulus

light, sound, smell

sensory receptors

eyes, ears, nose

perception

visual, auditory, olfactory areas

sensation

the process of detecting external events by the sense organs

Transduction

process in which physical or chemical stimulation is converted into a neural impulse that is delayed to the brain

perception

involves attending to, organizing and interpreting stimuli that we sense

absolute threshold

the minimum amount of energy or quantity of a stimulus required for it to be reliably detected at least 50% of the time it is presented

difference threshold

smallest difference between two stimuli that a subject can detect

Signal detection theory

how we make decisions under conditions of uncertainty

• thresholds can vary depending on the individual or context in which decision is made

correct responses

hit - detecting the stimulus when it is present
correct rejection - not detecting the stimulus when it is absent

incorrect responses

miss - failing to detect the stimulus when it is presented
false alarm - detecting the stimulus when it is absent

Subliminal stimuli

presented to a person below their conscious threshold,

• can detect this without conscious awareness (activation in certain brain activity)
• effects are limited: will not make you do anything you wouldn't do.

Perceptual organization

process by which elements are organized to form perceptible objects (grouping and segration)

figure- ground principle:

objects and figures in our environment tend to stand out against its background

Gestalt principles: good continuation

objects that are partially covered by other objects are seen as continuing behind those objects
ex: Olympic rings

gestalt principles: proximity

brains tendency to organize information that is close together

Gestalt: similarity

objects that are similar depending on their shape, size and colour.

gestalt principle: closure

fill in the gaps when we see certain things.