psychophysical methods

What are psychophysical methods?

Techniques used to measure the relationship between physical stimuli and subjective psychological experience

What does psychophysics investigate?

How physical stimulus properties relate to perception

What is the main goal of psychophysics?

To quantify perception and sensory experience

Which areas can psychophysical methods investigate?

Perception, attention, fatigue, and decision-making biases

Why are psychophysical methods important in cognitive psychology?

They allow objective measurement of subjective experience

What is perception in psychophysics?

The interpretation of sensory information

What is a physical stimulus?

An objectively measurable property in the environment

What is subjective experience?

An individual’s personal perception of a stimulus

What is the Stroop effect?

Interference caused when the colour of a word conflicts with the word meaning

Example of the Stroop effect

The word “RED” written in blue ink

What does the Stroop effect demonstrate?

The automaticity of language processing

What does automaticity mean in cognition?

A process occurs rapidly and involuntarily with little conscious effort

Why is the Stroop task difficult?

Automatic reading interferes with colour naming

What cognitive process is measured by the Stroop task?

Inhibitory control and selective attention

What is the Point of Subjective Equality (PSE)?

The point at which two stimuli are perceived as equal

What does the Point of Subjective Equality measure?

Perceptual bias

What is perceptual bias?

A systematic distortion in perception

What is the Just Noticeable Difference (JND)?

The minimum detectable difference between two stimuli

What does the JND measure?

Sensitivity to stimulus differences

Who proposed the concept of the JND?

Weber

What is Weber’s Law?

The JND is proportional to the original stimulus intensity

What is the Weber fraction?

The ratio between the JND and the original stimulus intensity

According to Weber’s Law, what happens as stimulus intensity increases?

A larger change is required to notice a difference

Why is a difference of 10 dots easy to detect when starting from 10 dots?

The proportional change is large

Why is a difference of 10 dots difficult to detect when starting from 110 dots?

The proportional change is small

What does Weber’s Law suggest about perception?

Perception depends on proportional rather than absolute differences

What is the Ponzo illusion?

A visual illusion where identical lines appear different sizes due to depth cues

What causes the Ponzo illusion?

Perspective cues influence size perception

What does the Ponzo illusion demonstrate about perception?

Perception is influenced by context and assumptions about depth

Why is the upper line in the Ponzo illusion often perceived as larger?

It appears farther away, so the brain scales it as larger

What does the Ponzo illusion reveal about visual processing?

The brain interprets size using environmental cues

Did all participants necessarily experience the Ponzo illusion equally?

No, perceptual effects vary across individuals

What factors besides perception may influence performance in psychophysical tasks?

Attention, fatigue, motivation, and decision-making strategies

Why may laboratory psychophysical tasks feel unrealistic?

They simplify perception compared to real-world experiences

What is ecological validity?

The extent to which findings generalise to real-world situations

What can psychophysical tasks tell us about cognition?

How sensory systems process and interpret stimuli

What can psychophysical tasks NOT fully explain?

Complex real-world cognition and behaviour

What is the Müller-Lyer illusion?

A visual illusion where lines of equal length appear different due to arrow-like endings

What does the Müller-Lyer illusion demonstrate?

Context influences size and length perception

What is the overall aim of psychophysical research?

To measure the limits and mechanisms of perception

How can psychophysics be applied in everyday life?

Understanding perception in activities such as driving

Why is perception considered constructive rather than passive?

The brain actively interprets sensory input using context and expectations