Monday, October 18 th, 2010 Objective: Develop an understanding of our senses review of where we are going this unit review of where we are going this unit What is Sensation and Perception What is Sensation and Perception View a movie to review where we are going View a movie to review where we are going  Do Now:  Write down our senses and each one’s purpose  What do you think sensation and perception mean?  Hand in your Project!

 Sensation – what occurs when a stimulus activates a receptor  Perception – the organization of sensory information into meaningful experiences

 Sensation and Perception Sensation and Perception Sensation and Perception Sensory processing and adaptationSensory processing and adaptation VisionVision The Other Senses:The Other Senses: Hearing Hearing Touch Touch Taste Taste Smell Smell PerceptionPerception Subliminal MessagesSubliminal Messages What is real?What is real?

Tuesday, October 19 th Today’s Goals discussion of our senses discussion of our senses discuss terms used in discussing our sensations discuss terms used in discussing our sensations Experiment to understand absolute threshold Experiment to understand absolute threshold  Do Now What are our 6 senses?What are our 6 senses?  Homework Evaluating our sensesEvaluating our senses

How many senses do we have?  The five we always remember, but we really do have a 6th sense….not seeing dead people, but our sense of balance.

What is the difference? SensationPerception

Absolute Threshold   The weakest amount of a stimulus necessary to produce a sensation 50% of the time. sight Candle flame 30 miles away hearing Ticking 20 feet away taste Tsp sugar in 2 gallons water smell 1 drop of perfume in a house touch Bees wing falling a distance of one centimeter

Difference Threshold   The smallest change in a physical stimulus that can be noticed half the time.   Do you notice another book in your bag if you already have 5 in it?

Signal detection theory  Study of people’s tendencies to make correct judgments in detecting the presence of stimuli. Combines concept of ability to detect with one’s own judgments. ?????????????????

EXAMPLES OF THE SIGNAL DETECTION THEORY The Classic Radar Operator Example The Shower/Phone Example The Eye Exam Signal: Are there actually enemy aircraft indicated on the radar screen? YesNo Decision: are they enemy Aircraft? YesHitFalse Alarm NoMissCorrect Rejection

Weber’s Law  The larger or stronger a stimulus, the larger the change required for a person to notice that anything has happened to it.  This increase in a stimulus need to produce a just-noticable difference is constant: dR = C * R  "equal relative increments of stimuli are proportional to equal increments of sensation."

Is the Room too Dark? Well, to see the SAME level of improvement…  1 candle x 10 = 10 candles  10 candles x 10 = 100 candles  And for the same improvement again,  100 candles x 10 = 1000 candles!

EXPERIMENT TIME! Also, handout homework – rank your senses

Why are we doing this?  Rationale – Psychology is often considered a “hard” (versus “easy” science) because of the complexity of measuring concept of interest. Although one would think that physical stimuli would be easily measured, psychological reaction to a stimuli is not so easily measured. Today, we will evaluate the concept of absolute threshold in order to understand why this is so hard to precisely determine, as well as to further understand how one studies sensation and perception.  To determine absolute threshold of the sugar water using two different methods Method of limits – using ascending on descending order Method of limits – using ascending on descending order Method of Constant Stimuli – using Method of Constant Stimuli – using

Procedure  Break into groups of four subject (blindfolded) subject (blindfolded) Experimenter (hands water to subject) Experimenter (hands water to subject) Recorder (Puts results on the worksheet) Recorder (Puts results on the worksheet) Math wiz (averages a chart) Math wiz (averages a chart)  Supplies blindfold blindfold 10 small cups (labeled 1-10) 10 small cups (labeled 1-10) Fill each small cup with samples from the larger cups. Fill each small cup with samples from the larger cups. calculator calculator

 Procedure 1 (method of limits) – give subject sips in ascending and descending 4 times; average and report mean. Record response of subject.  Procedure 2 – Give sips according to preset random order. Record responses  Finish any final calculations and report results

Period 1 Group 1Group 2Group 3Group 4Group 5 Limits threshold (mean) Constant Stimuli threshold

Period 9 Group 1Group 2Group 3Group 4Group 5 Limits threshold (mean) Constant Stimuli threshold