Sensation and Perception

Sensation and Perception

Icebreaker?

What is one thing you are grateful today?

Lets Review

1. If a toy car rolls on different surfaces, then the distance it travels will change.

2. If someone watches a motivational video before a test, then their performance will improve.

3. Trait: Widow’s peak (W = widow’s peak, w = straight hairline)
   One parent is Ww (heterozygous), and the other is ww (homozygous recessive).

4. Trait: Freckles (F = freckles, f = no freckles)
   Two heterozygous parents (Ff x Ff) have a child.

Sensation vs. Perception

Sensation occurs when sensory receptors detect sensory stimuli.

Perception involves the organization, interpretation, and conscious experience of those sensations.

Sensation vs Perception

Sensation

Definition: The process of detecting physical energy (stimuli) from the environment and converting it into neural signals.

What It Involves: Your sense organs (eyes, ears, skin, nose, tongue) picking up information.

Example: Light hits your eyes, and your retina senses brightness and color.

It's about: Receiving raw data from the environment.

Perception

Definition: The process of organizing, interpreting, and giving meaning to the sensory information.

What It Involves: Your brain making sense of what your senses detect.

Example: You recognize that the colors and shapes you see form an image of a tree.

It's about: Understanding what the data means.

Sensation

Transduction: the conversion from sensory stimulus energy to action potential.

Stimulus: Light enters the eye and hits the retina.

Transduction: Specialized cells in the retina called photoreceptors (rods and cones) convert light energy into electrical signals.

Then: These signals are sent via the optic nerve to the brain for processing.

Absolute threshold: refers to the minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time.
-e.g. how dim a light can be, how low a sound (50% of the time)

Just noticeable difference (difference threshold): difference in stimuli required to detect a difference between the stimuli

Perception

Perception involves both bottom-up and top-down processing. 

Top Down vs Bottom Up Processing

Bottom up begins with the external stimulus — such as a tree or the smell of cookies — and then that sensory information moves to the brain for analysis.

For instance, if you suddenly detect a sweet chocolaty smell wafting through the house, you might then determine that someone in your home is baking chocolate chip cookies.

To determine this, you didn’t need any other context or information — you simply used the sweet smell (the stimulus or raw data) to make your analysis. Your perception didn’t require prior knowledge that anyone was baking cookies.

Top-down processing is when our thinking influences how we see (understand/perceive) the environment.

Top-Down vs Bottom-Up Activities

Can you read this:
"Aoccdrnig to rscheearch at Cmabrigde Uinervtisy..."


Sensory Deprivation Activity

Attention

Attention plays a significant role in determining what is sensed versus what is perceived.

Daniel Simons and Christopher Chabris (1999) https://www.youtube.com/watch?v=vJG698U2Mvo

Inattentional blindness is the failure to notice something that is completely visible because the person was actively attending to something else and did not pay attention to other things.

What can affect attention?

Motivation to detect a meaningful stimulus can shift our ability to discriminate between a true sensory stimulus and background noise. e.g. waiting for an important phone call.

Our perceptions can also be affected by our beliefs, values, prejudices, expectations, and life experiences.
https://www.youtube.com/watch?v=OCs_Ja4Xj8o

Children described as thrill seekers are more likely to show taste preferences for intense sour flavors (Liem, Westerbeek, Wolterink, Kok, & de Graaf, 2004), which suggests that basic aspects of personality might affect perception.

Vision

The visual system constructs a mental representation of the world around us.

​https://www.youtube.com/watch?v=TY1giZgddAs

Auditory System

Our auditory system converts pressure waves into meaningful sounds.

​https://www.youtube.com/watch?v=LkGOGzpbrCk

The Chemical Senses

Taste (gustation) and smell (olfaction) are called chemical senses because both have sensory receptors that respond to molecules in the food we eat or in the air we breathe.

https://www.youtube.com/watch?v=mFm3yA1nslE&list=PLnn8Ibw--Uwsik3LMI5eZHidk6ITKT680

Touch

A number of receptors are distributed throughout the skin to respond to various touch-related stimuli.

​https://www.youtube.com/watch?v=udzhuFz3HKw

The Vestibular Sense

The vestibular sense contributes to our ability to maintain balance and body posture.

​https://www.youtube.com/watch?v=P3aYqxGesqs

Activity

1. Bottom-up processing is when the environment (stimuli) influence our thinking
2. Top-down processing is when our thinking influences how we see (understand/perceive) the environment.

Give and example of top-down and bottom-up processing occur with each sense.