PSYC 213 Lecture 5 – Visual Perception- Context and Theories.docx

Lecture 5 – Visual Perception: Context and Theories
Last Class: Sensation versus Perception
 Sensation –
o Occurs in the sensory organs.
o Energy from a physical stimulus in the environment that is picked up by sense
organs.
 Light, sound, smell, etc.
 Translates this into some sort of neural impulse or signal.
 Perception –
o Follows sensation.
o When the brain organizes sensed information (organizes those impulses), and
translates it/interprets it as something meaningful.
 Perception – understanding what is around us.
McGurk Effect and the Brain
We talked about how different senses might interact…
People perceive speech as what they see…
 Compared brain activity for people who experienced the McGurk effect and those people
who did not experience this effect.
 The left superior temporal sulcus is important for audiovisual integration during speech
perception.
o More active for people who experienced the McGurk effect.
 Region is important for integrating senses – so if it is activated more,
coupling audiovisual information more tightly that someone who is less
susceptible – more influenced by the McGurk effect.
 Underlying neuromechanisms for this effect.
o Individual differences are seen in the brain!
 How we take in information is represented in the brain.
From the Eyes…
 Early visual system –
o Step 1 – Light waves enter the eye and are focused on the retina, a thin layer of
tissue at the back of the eye.
o Step 2 – Photoreceptors in the retina (rods and cones) convert light to electrical
activity.
 Rods – dim light visions.
 Cones – colour and detail.
o Step 3 – This electrical signal is sent to bipolar cells then onto ganglion cells.