Kitten Carousel October 13
Bellringer Define these two terms the best you can: Sensation: Perception:
• Sensation: the five senses detecting stimuli – SEEING – When you touch something, nerves in your hand send a message up your spinal chord and into your brain. – Objective Physical NRG Receptors • Perception: making meaning out of sensory information – BELIEVING – Brain Signals Meaning (This delicious taste I’m sensing is a fruit) – SUBJECTIVE
Background • The debate between nature and nurture is the basis of most research into the development of perception. • There are five ways in which psychologists have attempted to study this debate: – – – by studying human babies, or neonates by studying cataract patients by studying animals by studying different cultures by studying adaptation
Nature and Nurture The degree to which human behaviour is determined by genetics/biology (nature) or learned through interacting with the environment (nurture)
Nurture • An individuals behaviour is determined by the environment- the things people teach them, the things they observe, and because of the different situations they are in. • Also a determinist view- proposes all human behaviour is the result of interactions with the environment.
Nurture • Behaviourist theories are nurture theories: - Behaviour is shaped by interactions with the environment. • Born an empty vessel- waiting to be filled up by experiences gained from environmental interaction. • No limit to what they can achieve: -Depends on quality of external influences and NOT genes. • The quality of the environment is KEY: -You can become anything provided the environment is right.
Background • Those who support the nature view point believe that humans are born with all their perceptual functions ready to be used – Bottom up theories of processing: also known as "small chunk" processing, suggests that we perceive our environment by starting with the smaller, more fine details then building upward until we have a solid representation of it in our minds
• Bottom Up Processing: sensation, starts with STIMULI from the outside world – Begins with your 5 senses and ends with brain activity – You SEE the lines • Travels to brain • Physical energy from the outside world transformed into neural signals • 5 senses pick up stimulus (input)
Background • Those who support the nurture view believe that perceptual abilities have to be learned and adapted to – Top down theories of processing: also known as "large chunk" processing, states that we form perceptions of our environment by starting with the larger concepts and then working our way down to the finer details of that concept
• Top Down Processing: Perception, starts with experience, prior knowledge and expectations – You make MEANING of the lines – Your experience (what you saw before the image) changed your perception 1 2 3 • Experience, expectations and prior knowledge • Interpretation of stimulus • Meaning
For Example • You listen to a song for the first time. You pay careful attention to the song itself, the beat, the instruments, the lyrics and the melody to decide if you like it or not. – BOTTOM UP PROCESSING • You hear the first beat of your favorite song and you instantly feel excited. You hear the whole song playing in your head and it brings back memories of good times. – TOP DOWN PROCESSING
Group Practice • A child eats a strawberry, a raspberry ice pop and a red lollypop, and now thinks that all red things are sweet. 1. 2. 3. 4. 5. What is the sensation? Top down or bottom up? What is the perception? Top down or bottom up? What do his perceptions draw on?
Held & Hein (1963) Movement-produced Stimulation in the Development of Visually Guided Behavior (aka depth perception) Create as many note cards as possible for this study based ONLY on what you read. Held and Hein (1963) -background/aim -method/procedures -sample -results/findings -conclusion -strengths/weaknesses of study (2 EACH)
Research Question Does an individual need to physically move themselves around when they experience visual changes in order to develop their perceptual skills?
Aim To test whether self-produced movements related to changes in stimulation are essential for the development of certain perceptions
Method • Laboratory experiment – IV? DV? – Control? • Yoked control design – In the yoked control procedure, the rate of responding by an experimental subject is compared to that by a control subject, but the two subjects are yoked in some meaningful way – In this study, the passive kitten receives responseindependent feedback while the active kitten receives response-dependent feedback
Subjects • Ten pairs of kittens were used; each pair from a different litter – In each pair there was one ‘active’ (A) and one ‘passive’ (P). - 8 pairs = “Group X” , brought up in darkness until they were 8 -12 weeks old, then they were exposed to the apparatus - 2 pairs = “Group Y”, exposed to patterned interior of laboratory while restrained from 2 – 10 weeks old for 3 hours a day
Procedure Each pair was attached to a ‘carousel’ which was driven by the movements of kitten A. A could move up, down, toward or away from the center, and rotate clockwise or counterclockwise.
Procedure Kitten B was also attached to the ‘carousel’ but was carried in a basket so it could not control its own movements. It moved exactly the way kitten A moved. The ‘carousel’ was housed in a cylinder with black, white, and metal-colored vertical strips on the inside walls (STIMULI) The center of the ‘carousel was also striped and prevented the kittens from seeing one another.
The kittens were receiving the same visual stimulation but the difference was in their movement: one moved actively (self-generated movement) while the other moved passively (no control over movement).
Procedure • None of them received light before the experiment. They were all raised in darkness from birth. • The point of all of this was that both kittens learned to see the world receiving the same visual stimulation. The only difference between the kittens was that the one moved actively, the other was moved passively.
Procedure • The pairs spent 3 hours per day in the apparatus for 6 weeks. • When not in the apparatus all kittens were housed in darkness with their mother and littermates
3 PERCEPTUAL TESTS WERE ADMINISTERED
Procedure & Results PERCEPTION TESTS TEST 1: Visually-guided paw placement: – the kitten was held by the experimenter and was carried down to the edge of the table. – A kitten with normal visual experience extends its paws ready to make contact with the surface.
Procedure & Results PERCEPTION TESTS TEST #2: Avoidance of a visual cliff: • The kitten was placed onto a transparent cliffshaped block. It was placed onto the center. One side looked ‘shallow’ and the other looked ‘deep’. • A kitten with normal visual experience completely avoids the deep-looking side because they have a perception of different depths.
Procedure & Results PERCEPTION TESTS TEST #3 Blink to an approaching object: • the kitten was held still in a standing position and the experimenter brought his hand quickly towards the kitten’s face (stopping just in front of it). • A kitten with normal visual experience blinks in response.
3 SENSORY TESTS WERE ADMINISTERED
Procedure & Results SENSORY TESTS TEST #1: Visual pursuit of a moving object: the kitten was shown the experimenter’s hand moving slowly in front of it. The movement of the kitten’s eyes was recorded. A kitten with normal visual experience follows the movement with its eyes.
Procedure & Results SENSORY TESTS TEST #2: Pupillary reflex to light: • A flashlight beam was moved across the eye and the change in pupil size was noted. • The pupil of a kitten with normal visual experience shrinks in response.
Procedure & Results PERCEPTION TESTS TEST #3: Tactual placing response: • the kitten was held as in the paw placement test but its front paws were put against the vertical surface of the table. • A kitten with normal visual experience responds by moving its paws to the horizontal surface.
RESULTS All the ‘active’ kittens had developed the following: • a normal visually-guided paw placement response • a normal blinking response • a normal level of depth perception • a normal response to following movements
RESULTS The ‘passive’ kittens had not developed any of these perceptual abilities; • they would not blink in response to approaching objects, • they had no sense of depth perception, • they did not adjust their body positions.
Findings – This was reversed! • Following the 48 hours of freedom in a lighted room the passive kittens were retested. – They displayed normal visually-guided pawplacement and performed all descents to the shallow side of the visual cliff.
Conclusions • Self-actuated movement is necessary in order to develop the normal visual perception with depth. • Our movement in the world gives the dimension of depth to mere visual sensations. • Movement is the key to understanding the vision.
Strengths • Control – Experience of the kittens was matched • • • speed of travel direction of travel distance travelled height from the floor contact with the floor the view of the apparatus • This shows that the differences were due to the kittens visual deficits were due to the fact that its movements were not self-actuated
Weaknesses • May have merely distorted inborn abilities rather than proved that the abilities were learned (Ecological validity? ) • Can this generalize to all mammals? Even people? • Ethics of working with animals
Writing Practice 1. Describe one difference and one similarity in the early visual experience of the kittens in group X compared with the kittens in group Y. 2. Evaluate the ecological validity of Held & Hein (1997). 3. Do the findings of this study support the nature or the nurture viewpoint? Explain.