module 4.1 pysc

sensation

detection of physical energy by sense organs

Ex: vision hearing, touch smelling

perception

Brian’s interpretation of sensory input.

be cautious of naive realism what we see is not 100 percent accurate and our brain fills in missing info

bottom up processing

begins with sensory info coming from the environment.

• Sensory receptors detect features such as light, sound,

  pressure, or temperature.

top down processing

Our brain uses knowledge, expectations, and past experiences to interpret sensory information.

• The same sensory information can therefore be interpreted differently depending on context.

what does sensation allow us to detect

info from our environment

When you expected certain lyrics, you were more likely to hear those words

that’s an example of top down processing

First play =

bottom up

after seeing the lyrics=

top down

transduction stimulus

something happens

physical energy from the enviorment

Ex; light, sound, heat, pressure

transduction sensation

receptors detect it

your sensory receptors detect the stimlus

Ex; eyes detect light

Transduction

convert it

Receptors convert physical energy into neural signals.

Transduction = convert into neural signals

neural signals

travel

Neural signals travel to the central nervous system (CNS).

Perception

• The brain organizes and interprets the information.

• This is when you understand what you're sensing.

transduction easy way to remember

Something happens → receptors detect it → convert it → brain receives it → brain understands it.

sensory adaption

Sensitivity to a constant, unchanging stimulus decreases over time.

When a stimulus first appears, we tend to notice it strongly.

• If it remains unchanged, our sensory system may respond less

strongly.

• Example: After wearing a watch for several minutes, you may stop noticing it against your skin.

• Why useful? It allows us to focus more attention on new or changing information.

psychophysics what is the absolute threshold?

The lowest level of a stimulus detected 50% of the time.

Example: How quiet can a sound become before you can no longer reliably hear it?

Difference threshold

The smallest difference between two stimuli that can be detected.

• Example: How much louder must the TV become before you notice the volume changed?

weber’s law

Weber’s Law says that the smallest noticeable difference between two stimuli depends on the original stimulus.

Ex:

• If you are holding 10 kg, you might notice a small increase.

• If you are holding 100 kg, you need a much larger increase to notice the difference.

signal detection theory

noise can decrease ability to detect signal

signal detection theory

Signal detection theory explains how we distinguish an important signal from background noise.

detection can be affected by: attention, expectations, motivation, fatigue, environmental noise.

what are the 4 possible outcomes of detection theory

hi, miss, false alarm, correct rejection.

key point to remember of detection theory

Sensory detection involves both the strength of the signal and the person detecting it.

cross modal perception

Multisensory perception means the brain combines information from different senses.

Example:
What you see can change what you think you hear.

The McGurk Effect shows that visual information can change what we hear.

For example, seeing someone's mouth make one sound while hearing another can make your brain perceive a different sound.

double duty

some brain areas can process information from more than one sense.

• Auditory cortex → mainly hearing, but can also respond to touch.

• Visual information → can improve touch perception in the somatosensory cortex.

• Blind people reading Braille → can activate the visual cortex, even though they aren't using vision.

Selective attention: Focusing

awareness on particular stimuli while filtering others.

filter theory of attention

you focus on important info and ignore distractions

Ex; you listen to your teacher and ignore other students talking

cocktail party effect

suddenly attend to important info in converstation

Ex: crowd at party says your name

Inattentional blindness

Failure to notice unexpected item Person driving to work does not notice

man lying in the middle of road and accidently hits him.

Change Blindness

failture to notice obvious change.

bill is talking on his cellphone at a red light. he doesn’t notice the light change ti green and stays stopped. Driver behind beeps at them.

Binding problem:

Putting pieces together

how do the parts of perceiving an object come to be perceived as a whole object