TOK: Ways of Knowing Sense Perception

We perceive the world through our 5 senses. Our 5 senses are: Sight Hearing Touch Smell Taste

Sense Perception is an important dimension of our understanding of the World The channel of communication between ourselves and the outside world Its function and scope should be examined and critically evaluated

Common Sense Realism The way we perceive the world mirrors the way the world is

Perception can be thought of consisting of two distinct parts Sensation: The part provided by the world around us Interpretation: The part provided by our minds

Our experience of the world is affected not only by what is ‘out there’ but also by our sense organs AND our minds

Questions to Discuss To what extent do our senses give us knowledge of the world as it really is? What role does what we expect to see, or are used to seeing, play in what we observe? What is meant by the saying ‘knowledge is the true organ of sight, not the eyes’? Do you think perception is a more important source of knowledge in some subjects rather than others?

"INNOCENT EYE?" Perception influenced (at the very least) by: Attention (we cannot process everything that reaches our senses) Convention & cultural aspects (e.g. right angles, perspective) Belief / Language (to what extent do we perceive what is incongruent to our past experiences?) Expectations (familiar sights, ET's) To organize sense perceptions in our brains, we require, at the very least, the following learned factors: Context • Inference • Concepts • Experience • Interpretation

What's wrong with this figure?                                      What's wrong with this figure? 

So what's Happening?      The is a physical model of an impossible staircase designed by genetist Lionel Penrose. It is the first impossible object ever made and served as an inspiration for M. C. Escher's famous print that incorporates this staircase, "Ascending and Descending." The actual model is separated at the right stair, but you can't see the split, because your visual system assumes that it is seeing this model from a non-accidental point of view; hence, it assumes that the stairs are joined.       Although the staircase is conceptually impossible, it does not interfere with your perception of it. In fact, the paradox is not even apparent to many people.                                                                                                                                                    

Synesthesia Synesthesia is the extraordinary sensory condition in which stimulation of one modality leads to a perceptual experience in another. Literally, the term means “to perceive together.” What does this mean?

Neurologist Richard Cytowic describes the case of Michael Watson, who feels shapes when he tastes or smells food. After tasting a sauce he was making for chicken, he complained, “there aren’t enough points on the chicken.” When Cytowic asked him what he meant, Watson explained that all flavors had a shape to him: “I wanted the taste of this chicken to be a pointed shape, but it came out all round. Well, I mean it’s spherical. I can’t serve this if it doesn’t have points.”

A A Synesthesia Perceived stimulus Associated Experience (inducer) (concurrent) A A Synaesthetic experiences are both consistent and automatic

Sensation refers to how we detect physical energy from the environment and encode it as neural signals. Perception refers to how we select, organize and interpret this information. Sensation provides the raw information and perception constructs into our experiences.

According to psychologist Douglas Bloomquist, in viewing puzzle pictures, we readily come to appreciate that perception is an active process. We struggle to impose some organization upon the meaningless array we are sensing. We may even generate hypotheses about the figures, then test them by searching the picture for features that are congruent with our hypotheses. After a few minutes of unsuccessful inspection, we are likely to experience some degree of frustration

The subject in the picture is a Dalmatian dog The subject in the picture is a Dalmatian dog. Why is it difficult to see? First, it is not a complete picture. Psychologist K.M. Dallenback suggests that even when asked to see a dog, we may adopt a set to perceive an entire figure, not a partial one. A related explanation is that the contours are insufficient to differentiate figure from ground. Both figure and ground are made up of irregular spots of black and white.

Want More fun with illusions? Well….Ok 

Variability of the Absolute Threshold An absolute threshold is defined as the minimum amount of stimulation a person needs for a particular stimulus to be detected 50 percent of the time.

The Absolute Thresholds for the “5” senses in humans are the following: 1. Vision: Seeing a candle flame 30 miles away on a clear night. 2. Hearing: Hearing a watch ticking 20 feet away. 3. Taste: Tasting 1 teaspoon of sugar dissolved into 2 gallons of water. 4. Smell: Smelling one drop of perfume in a 3 room house. 5. Touch: Feeling a bee’s wing falling a distance of one centimeter onto your cheek.