perception final exam *ALL UNITS

What is perception?

A conscious experience resulting from stimulation of the senses.

How does the brain function similarly to a computer?

Both process information and respond to stimuli based on past experiences.

What is the role of sensory receptors in perception?

They depend on the properties of the sensory receptors to detect stimuli.

What is the perceptual process?

The process that begins with environmental stimuli and ends with behavioral responses.

List the steps in the perceptual process.

1. Stimulus in the environment 2. Light reflected and focused 3. Receptor processes 4. Neural processing 5. Perception 6. Recognition 7. Action.

What is the difference between sensation and perception?

Sensation is the detection of elementary properties of a stimulus, while perception is the conscious awareness of those stimuli.

What is a distal stimulus?

A stimulus that is distant and exists in the environment, such as a tree.

What is the principle of transformation?

The process by which stimuli and responses are transformed between the distal stimulus and perception.

What happens during neural processing?

Electrical signals are transmitted through interconnected neurons, changing as they travel to the brain.

What are the primary lobes of the cerebral cortex involved in perception?

Occipital lobe (vision), Temporal lobe (hearing), Parietal lobe (touch), Frontal lobe (coordination of information).

What is visual form agnosia?

An inability to recognize objects despite having intact vision.

What is bottom-up processing?

Processing based on stimuli reaching the receptors.

What is top-down processing?

Processing based on knowledge and experiences.

What is psychophysics?

The branch of perception that studies the quantitative relationships between physical stimulation and perceptual events.

Who is Fechner and what did he contribute to psychophysics?

Fechner proposed that the mind and body are two sides of the same reality and studied the relationship between stimulus magnitude and sensation.

What is an absolute threshold?

The minimum intensity needed to detect a stimulus 50% of the time.

What is a difference threshold (just noticeable difference)?

The smallest detectable difference between two stimuli.

What is Weber's Law?

The principle stating that the just noticeable difference (JND) is a constant fraction of the comparison stimulus.

What is the significance of the Rat Man Demonstration?

It shows how recently acquired knowledge can influence perception.

What is the main problem of perception according to John Locke?

How does our physical world reach our consciousness?

What does the objectivist view of perception suggest?

That our senses accurately reflect the physical world.

What does the subjectivist view of perception suggest?

That perception is influenced by individual interpretation and learned experiences.

What is the synthetic view of perception?

It posits that we perceive within the limits of our nervous system, which has evolved to reflect portions of the world accurately.

What is the role of knowledge in perception?

Knowledge provides context and influences how stimuli are interpreted.

What is the relationship between physical stimulation and perception according to Fechner?

As physical stimulation increases, the perception of the object also increases.

What is the purpose of classical psychophysical methods?

To study perception thresholds and detect mechanisms responsible for experiences.

What is the relationship between stimulus intensity and perceived sensation according to Fechner's interpretation?

The relationship is logarithmic, expressed as S = k log R.

What does JND stand for in psychophysics?

Just Noticeable Difference.

How does the intensity of a stimulus affect the JND?

As the stimulus becomes more intense, a larger change in stimulus is needed to perceive a difference.

What are the three methods Fechner proposed for measuring thresholds?

Methods of Limits, Method of Adjustment, and Method of Constant Stimuli.

What is the advantage of the Method of Limits?

It is quick and simple.

What is a disadvantage of the Method of Limits?

It can be biased by expectations or habituation.

How does the Method of Adjustment work?

The observer adjusts the intensity until the stimulus is just detectable.

What is a disadvantage of the Method of Adjustment?

Results can be subjective and variable.

What is the most accurate method for measuring thresholds according to Fechner?

Method of Constant Stimuli.

What does the term 'discriminability' (d') refer to in Signal Detection Theory?

It refers to the sensitivity to the signal, indicated by the distance between the means of the signal.

What are the four possible outcomes in Signal Detection Theory?

Hit, Miss, False Alarm, Correct Reject.

What does a liberal criterion in Signal Detection Theory imply?

It leads to more hits and more false alarms, indicating a tendency to report a signal that may not be present.

What is the significance of Stevens' Power Law in perception?

It describes how perceived magnitude (P) relates to stimulus intensity (I) as P = kI^n, where n determines the curve shape.

What does it mean if n < 1 in Stevens' Power Law?

The response compresses, indicating a decelerating curve.

What does it mean if n > 1 in Stevens' Power Law?

The response expands, indicating an accelerating curve.

What is the absolute threshold in detection tasks?

It is the smallest intensity of a stimulus that can be perceived.

What does the term 'matching' refer to in psychophysics?

It involves adjusting one of two stimuli so that they appear or sound the same in some respect.

What is the purpose of the Forced Choice method in detection tasks?

Participants must choose between alternatives, even if unsure, to measure detection accuracy.

What is the difference between detection and discrimination in psychophysics?

Detection is about perceiving a stimulus, while discrimination involves determining which of two stimuli has greater intensity.

What does the term 'criterion' refer to in Signal Detection Theory?

It refers to the tendency of a person to say yes or no, determining the threshold for detection.

What does JND stand for in sensory measurement?

Just Noticeable Difference

What are the two types of data researchers measure in sensory perception?

Behavioral and physiological relationships

What theory suggests the nervous system is a continuous network?

Reticular Theory (Camillo Golgi)

What does the Neuron Doctrine state about sensation?

The nature of a sensation depends on which sensory fibers are stimulated.

What is Magnetic Resonance Imaging (MRI)?

A medical imaging technology that forms images using a static magnetic field and radio frequency energy.

What does the ROC Curve represent in signal detection theory?

The relationship between false alarms and hits.

What does a higher d-prime (d') indicate on the ROC Curve?

The curve is closer to the upper left corner, indicating more hits and fewer false alarms.

What are the two criteria used in signal detection theory?

Conservative criterion and liberal criterion.

What is the role of distal stimuli in vision?

Light is reflected and focused to create an image on the retina.

What is the wavelength range of visible light?

400-700 nm

What are the two types of visual receptors in the eye?

Rods and cones.

What is the function of the pupil in the eye?

It allows light to enter the eye.

What does the cornea do?

It focuses stimuli coming from the pupil to form sharp images on the retina.

What is sound defined as?

A pattern of pressure fluctuations in the air that travels as a wave.

What is the speed of sound in air?

~340 m/s

What does amplitude refer to in sound?

Sound pressure level, which corresponds to loudness.

What is frequency in the context of sound?

The rate of modulation, which corresponds to pitch.

What is the decibel scale?

A logarithmic scale used to measure sound intensity.

What is the threshold of hearing?

The minimum sound level that can be heard, which varies by frequency.

What is the function of the outer ear?

To collect sound and aid in localization.

What are the ossicles in the middle ear?

Three small bones (malleus, incus, stapes) that transmit vibrations to the cochlea.

What is the cochlea?

A snail-shaped, fluid-filled structure in the inner ear responsible for hearing.

What is the Organ of Corti?

The structure in the cochlea that contains hair cells and is the site of transduction.

What are binaural cues in sound localization?

Interaural time difference and interaural level difference.

What is the cone of confusion?

An area where sound localization is ambiguous, resolved by head and pinna cues.

What is the Head Related Transfer Function?

It describes how the shape of the pinna and torso filter sound, providing cues for elevation and front-back distinction.

What are the three main cues for Auditory Distance Perception?

Relative intensity, spectral composition, and reverberation.

How does relative intensity contribute to distance perception?

Closer sounds are perceived as louder.

What effect does reverberation have on sound perception?

More reverberation makes a sound source appear further away.

What is Auditory Scene Analysis?

It is the process by which the auditory system groups and segregates sounds.

What is segregation in auditory perception?

The grouping of sounds into distinct perceptual streams.

What is the Continuity Effect?

The perception of continuous sound even when it is interrupted.

What is the Restoration Effect?

The brain fills in missing sounds, such as syllables in interrupted speech.

What is categorical perception in speech?

Gradual changes in acoustic signals are perceived as abrupt category shifts.

What is the McGurk Effect?

Visual information can influence auditory speech perception, leading to a different perceived sound.

What is the role of top-down processing in auditory perception?

Knowledge of language and context influences perception, making speech easier to understand in familiar languages.

What happens when sound arrives at the cochlea?

A traveling wave along the basilar membrane peaks at different locations based on frequency.

What is the difference between place code and temporal code?

Place code indicates frequency by which auditory neurons fire, while temporal code relates to the timing of neuron firing.

What is the firing-rate hypothesis in loudness perception?

A single auditory nerve fiber increases its firing rate as intensity increases.

What is the number-of-neurons hypothesis?

As sound level rises, more neurons are recruited to fire, contributing to the perception of loudness.

What are the main cues for sound localization?

Temporal cues, sound intensity cues, and spectral cues.

What is Interaural Intensity Difference (ILD)?

The difference in sound intensity between the two ears, used to determine the azimuth of a sound source.

What is Interaural Timing Difference (ITD)?

The difference in time it takes for sound to reach each ear, helping to localize sound direction.

How does the pinna contribute to sound localization?

It filters sound, affecting how sound is perceived based on its elevation.

What is the role of the MSO in auditory processing?

The Medial Superior Olive measures timing differences between inputs from the two ears.

What is the function of the Later Nucleus of the Superior Olive?

It measures intensity differences between sounds arriving at each ear.

What is the significance of broadband sounds in auditory perception?

They are colored differently depending on their elevation due to the filtering properties of the pinna.

What is the coincidence detector in auditory processing?

A mechanism that signals when two sounds occur simultaneously.

What is the significance of the cochlear implant's components?

It includes a microphone, frequency analyzer, transmitter, receiver, and electrodes to restore hearing.

What is the relationship between loudness and noise energy?

Loudness perception increases as noise energy spreads across a wider frequency range.

What is the role of auditory nerve fibers in sound perception?

They act like a bank of filters, each sensitive to specific frequencies.

What is the effect of indirect sounds in a concert hall?

Sounds reverberate off different objects, changing how the sound enters the ear.

What is the difference between fundamental frequency and harmonics?

A pure tone combined with harmonics creates a richer sound, perceived as coming from a common source.

What does virtual pitch refer to?

Pitch is not the same as frequency; it involves the separation of harmonics and frequency.