Exam 3 Study Guide

This guide covers two chapters. First, you will follow energy from the world into your senses, and see how the brain builds what you perceive. Then you will learn how experience changes behavior. Work one chapter at a time. Read the "what to know" part. Then cover the right side of each table and rebuild it from memory. Say the sequences out loud, in order. Finish each chapter with its ten self-test items. The cram sheet at the end puts it all on one page.

Chapter 5Sensation & Perception

What to know

Start with the two big words. Sensation is your senses picking up energy from the world and turning it into nerve signals. Perception is your brain sorting those signals and giving them meaning. The same light can reach two people in the same way. Yet they can perceive it very differently.

Information flows two ways. Bottom-up processing builds from the raw signal. You use it most with something new. Top-down processing uses what you know and expect. It helps you read messy handwriting. Almost all perception mixes both.

Every sense starts with transduction. That means changing one kind of energy into nerve signals. Photoreceptors do it in the eye. Hair cells do it in the ear. Receptors in the skin do it for touch.

Now the limits. Psychophysics studies how physical energy relates to what we sense. Gustav Fechner founded it. The absolute threshold is the weakest stimulus you can detect half the time. The difference threshold, or JND, is the smallest change you can detect half the time. Weber's law says the JND is a set fraction of the start, not a set amount. A stimulus below the absolute threshold is subliminal. When a stimulus stays the same, you slowly stop noticing it. That is sensory adaptation.

Signal detection theory adds a second dial. Catching a faint signal depends on how keen your senses are. It also depends on your decision criterion, or how ready you are to say yes. Every answer falls into one of four boxes: a hit, a miss, a false alarm, or a correct rejection.

Vision begins with light. Its wavelength sets the color, and its strength sets the brightness. Light passes the cornea, which does most of the focusing. Then it goes through the pupil, sized by the iris. The lens fine-tunes the focus by changing shape, which is called accommodation. The image lands on the retina. There, rods and cones do transduction. Signals pass to bipolar cells, then ganglion cells, then out the optic nerve. Where the nerve leaves, there is a blind spot. The fovea gives the sharpest vision.

Color has two theories, and both are right. The trichromatic theory of Young and Helmholtz says three cone types respond to short, medium, and long wavelengths. Hering's opponent-process theory says color is handled later in pairs: red and green, blue and yellow, black and white. Afterimages come from those pairs.

Sound is waves of pressure. Frequency is heard as pitch, and amplitude is heard as loudness. The outer ear gathers sound to the eardrum. Three middle-ear bones make it stronger. The cochlea carries the wave along the basilar membrane, where hair cells bend. That bending is transduction. Place theory explains high pitches. Frequency theory explains low pitches. The volley principle covers the middle.

Taste has five basics: sweet, sour, salty, bitter, and umami. Smell skips the thalamus and reaches the limbic system fast, which ties scent to memory. Flavor is mostly smell. Pain is not a simple measure of damage. The gate-control theory of Melzack and Wall says a spinal gate can block pain or let it through. Kinesthesia tracks your limbs. The vestibular sense tracks balance through the semicircular canals.

Last comes organization. Gestalt psychologists said we see organized wholes. We split figure from ground. We group by proximity, similarity, continuity, closure, and common fate. Depth comes from binocular cues, like retinal disparity and convergence, and monocular cues, like relative size and motion parallax. Perceptual constancy keeps objects stable as their images change. A perceptual set lets what you expect shape what you see. Illusions show these rules at work.

The four outcomes of signal detection

The two dials, drawn

Rods and cones

The eye, drawn

Theories of pitch

The cochlea, uncoiled

The other senses

Gestalt rules and depth cues

Sequences, in order

The path of light through the eye.

1. Cornea · bends the light the most.
2. Pupil · lets light in; the iris sets its size.
3. Lens · fine-tunes the focus by accommodation.
4. Retina · rods and cones do transduction.
5. Bipolar cells, then ganglion cells · pass the signal on.
6. Optic nerve · carries it to the brain.

The path of sound through the ear.

1. Pinna and ear canal · gather sound.
2. Eardrum · vibrates.
3. Malleus, incus, stapes · make the vibration stronger.
4. Oval window and cochlea · a wave rolls through the fluid.
5. Hair cells on the basilar membrane · bend, which is transduction.
6. Auditory nerve · carries the signal to the brain.

How to reason through the question types

Chapter 6Learning

What to know

Learning is a fairly lasting change in behavior or knowledge that comes from experience. Both parts matter. Changes from maturation, from reflexes and instincts, or from fatigue and drugs do not count.

The simplest kind is non-associative learning. It has just one stimulus that repeats. In habituation, the response gets smaller. In sensitization, the response gets bigger after a strong or scary stimulus.

Associative learning links two events. It has two big forms. Classical conditioning links two stimuli. Operant conditioning links a behavior to its consequence.

Ivan Pavlov found classical conditioning while studying digestion in dogs. Food is the unconditioned stimulus (US). Drooling at food is the unconditioned response (UR). A metronome starts as a neutral stimulus. After pairing, it becomes a conditioned stimulus (CS). Drooling at it is the conditioned response (CR).

Five processes shape a conditioned response. Acquisition builds the link, best when the CS comes just before the US. Extinction fades it when the CS comes alone. Spontaneous recovery brings it back after a rest. Generalization spreads it to similar stimuli. Discrimination narrows it to the exact CS. Robert Rescorla showed the CS must truly predict the US. Watson and Rayner's 1920 Little Albert study showed fear conditioning and generalization in one baby. It had serious flaws and would not be allowed today.

Edward Thorndike watched cats escape puzzle boxes and stated the law of effect. Behaviors with pleasing results get stronger. B. F. Skinner built this into operant conditioning, using the operant chamber. Classical conditioning works on automatic responses. Operant conditioning works on voluntary behaviors.

Every consequence has two features. Reinforcement makes a behavior more likely. Punishment makes it less likely. Positive means something is added. Negative means something is taken away. So negative reinforcement is taking away something unpleasant to make a behavior grow. It is not punishment. Primary reinforcers meet body needs. Secondary reinforcers, like money and praise, work by being linked with them. Punishment shows what not to do, but not what to do instead.

Shaping builds a new behavior by rewarding successive approximations, or steps closer and closer to the goal. Continuous reinforcement rewards every response. It is learned fast but quits fast. Partial reinforcement rewards only some responses, and it lasts longer. That is the partial reinforcement effect.

There are four partial schedules. Ratio schedules count responses. Interval schedules count time. Each can be fixed or variable. Variable-ratio gives the highest, most stubborn responding. Fixed-interval gives a scallop that speeds up near the deadline.

Albert Bandura showed observational learning, or modeling. In his 1961 Bobo doll study, children copied an adult who attacked a doll, with no reward of their own. Seeing a model punished cut copying. Seeing a model rewarded added little. When every child was offered a reward, all groups did the acts well. So consequences change performance, not learning. Modeling needs attention, retention, reproduction, and motivation.

The four parts of classical conditioning

Classical conditioning, drawn

The four consequences

The four schedules

Cumulative records, drawn

Sequences, in order

Classical conditioning over time.

1. Acquisition · pair the CS just before the US until the CS alone causes the CR.
2. Extinction · give the CS alone, again and again, and the CR fades.
3. Spontaneous recovery · after a rest, the CR comes back for a while.

Shaping a lever press.

1. Reward the rat for turning toward the lever.
2. Then only for walking up to it.
3. Then only for touching it.
4. Then only for a full press.

Bandura's four steps of modeling.

1. Attention · notice the model.
2. Retention · remember what they did.
3. Reproduction · be able to do it.
4. Motivation · want to do it.

How to reason through the question types

One pageCram sheet