Unit 4: Sensation and Perception

What is a Sense???

A sense is a system that translates information from outside the body into neural activity that can then be perceived by the brain

Sensations are the messages from the senses that make up the raw information sent to the nervous system

Flowchart for our Senses:

Sense of Hearing

The ear is our main sensory organ for hearingWhat we sense with our ear are called sound

-A repetitive fluctuation in the pressure of a medium, such as air.

-A sound is determined by its Amplitude, Wavelength, and Frequency

Amplitude/Loudness:

Amplitude is the difference between the peak and baseline of a waveform. (in this case sound)\

The higher the Amplitude, the louder the sound will be

Wavelength/Frequency:

Wavelength is the distance between one peak to the next in a waveform

The shorter the wavelength, the higher the frequency

Frequency is measured in hertz (Hz)

Frequency/Pitch:

Frequency us the number of complete waveforms, or cycles that pass by a given point in space every second

The Higher the frequency, the higher pitch of the sound, the lower the frequency of the sound

Timbre:

Timbre represents the quality of the sound that we hear

The better the sound quality, the better we can hear and identify the sound

Parts of our Sense of Hearing: Pinna

The Pinna (outer ear) is our accessory structure of our sense of hearing

It collects sound from the world around us

Parts of our Sense of Hearing: Ear Canal

The Ear Canal directs the sensations deeper into our ear and towards our eardrum (Tympanic Membrane)

Parts of our Sense of Hearing: Tympanic Membrane

The Tympanic Membrane (Ear Drum) creates vibrations that match the sound waves matching the waves striking it.

Parts of our Sense of Hearing: Cochlea

The spiral shaped, fluid filled part of our ear that transduces what we hear

Transduction: converting physical signals from the environment into encoded neural signals sent to the central nervous system.

Place Theory

Place Theory allows us to locate where a sound is coming from without actually seeing the sound being made

Light: What We Sense When We See

• We can see visible light• Light gives depth and color to all we see• Without light, we cannot see (duh!!!)

The Eyes: Accessory Parts

• Light enters the eye through the Cornea

• This is a convex and semitransparent protective layer of the eye

• Its job is to begin to focus the light entering the eye

The Eyes: Accessory Parts

• As light passes through the pupil, which is right behind the cornea, it becomes more focused

• Next, the light passes through the Iris which gives our eyes their color and adjusts the size of the pupil to let in more or less light

• The Lens is the last accessory part of the eye

The Eyes: Parts of Transduction

• The main part of transduction is the retina

• This complex organ is tasked with taking the light that has been focused and turned into an image in the back of the eye

• To do this, there are many specific structures within the retina

In the Retina: Photoreceptors

• Photoreceptors are specialized cells in the retina

• Within these photoreceptors are photopigments which are sensitive to light

• There are two types of photoreceptors

-Cones -Rods

In the Retina: Rods

• Rods, called such due to their shape, detect amounts of light

• When it is darker, and we cannot discriminate color well, we are using our rods to see

In the Retina: Cones

• Cones, called such due to their shape, interpret color

• Cones are located within the fovea

• Depending on the photopigment within the cone, it will pick up one of three colors

-Red, Green, Blue• To interpret other colors,

multiple cones must work together

Colorblindness

Some people are born with faulty cones and can only see 2 of the 3 colors

We call this colorblindness

Sense of Smell and Taste:

Olfaction: The sense of smellGustation: The sense of tasteThese senses are linked and rely on each other

Pheromones:

Chemicals that are released by one animal that are sensed by another animal which affect that animal’s behavior

Vemeronasal Organ:

An organ within our olfactory system that is sensitive to pheromones

Papillae:

Structures on the tongue that contain taste receptors or taste buds

These help us distinguish what we are eating

Sense of Touch

Every inch of our skin is covered by touch receptors

Our sense of touch, temperature, pain and kinesthesia are called our somatic senses

Gate Control Theory

The theory that a special part (gate) within the spinal cord allows pain to travel to the brain or stops its advance.

To pass the gate, the pain must be strong enough to be registered

Analgesia

In rare cases, people can have an absence of pain in a situation where they would normally feel pain

This could be caused by adrenalin or their senses being overloaded.

Vestibular Sense: Our 6th Sense

Every inch of our skin is covered by touch receptors

Our sense of touch, temperature, pain and kinesthesia are called our somatic senses

Kinesthesia:

Every inch of our skin is covered by touch receptors

Our sense of touch, temperature, pain and kinesthesia are called our somatic senses

Synesthesia: The Blending of our Senses

In some people, at certain times, our senses can be blended.

Some people can “taste” different colors, or “see” different smells

From 2011 AP Exam:

2. Savannah is a junior in high school and is preparing for an exam in her beginning Japanese course. The exam will consist of both written and spoken portions. Although it is her first course in Japanese, Savannah is confident that she will do very well on the exam.

A. Describe how each of the following relates to Savannah’s successful learning and performance. • Broca’s area • Use of phonemes • Modeling • Chunking

B. Describe how each of the following may hinder Savannah as she prepares for and takes the exam. • Encoding failure • Age and language acquisition

C. After the exam, Savannah tells her family and friends that she believes that she spoke fluently and did extremely well on the exam. Describe how each of the following concepts may have influenced her opinion. • Self-efficacy • Confirmation bias