Biopsych + sensation/perception

Biopsychology

• Evolution/Natural Selection: Darwin — traits aiding survival are passed on.

• Genetics/Inheritance: Genes (DNA segments) influence traits and behavior.

Nature vs. Nurture:

• Debate: Are we shaped more by biology (nature) or environment (nurture)?

Neurons:

• Parts:
  

  • Dendrites: Receive signals.

  • Soma: Cell body.

  • Axon: Sends signal.

  • Myelin sheath: Speeds impulses.

  • Axon terminals: Send signal to next neuron.

• Types: Sensory, motor, interneurons.

• Neurotransmitters (NTs):
  

  • Dopamine: Movement, pleasure.

  • Serotonin: Mood.

  • Acetylcholine (ACh): Muscle action, memory.

  • Norepinephrine: Alertness.

  • GABA: Inhibitory.

  • Glutamate: Excitatory.

  • Endorphins: Pain relief.

Nervous System:

• CNS: Brain + spinal cord.

• PNS: Everything else.
  

  • Somatic: Voluntary movement.

  • Autonomic: Involuntary functions.
    

    • Sympathetic: “Fight or flight.”

    • Parasympathetic: “Rest and digest.”

Three Brain Layers:

• Brainstem: Basic life functions (medulla, pons).

• Limbic System: Emotions, memory (amygdala, hippocampus, hypothalamus).

• Cerebral Cortex: Complex thought.

Lobes of the Cortex:

• Frontal: Planning, decisions, motor cortex.

• Parietal: Touch, sensory cortex.

• Temporal: Hearing, language.

• Occipital: Vision.

Cerebral Dominance:

• Left: Language, logic.

• Right: Spatial, creative tasks.

• Split Brain: Corpus callosum cut; hemispheres can’t communicate.

Sensation and Perception

Transduction: Conversion of physical stimulus to neural signal.

Sensory Adaptation: Decreased sensitivity after constant stimulation.

Thresholds:

• Absolute Threshold: Minimum stimulation to detect.

• JND (Difference Threshold): Smallest detectable difference.

Signal Detection Theory: Detecting a stimulus depends on expectations, fatigue, etc.

Vision:

• Retina: Contains rods (dim light) and cones (color).

• Fovea: Focus point of retina, high cone concentration.

• Optic nerve: Sends info to brain.

Hearing:

• Cochlea: Transduction of sound waves.

• Hair cells: Receptors in cochlea.

• Place Theory: Pitch = location of hair cells.

• Frequency Theory: Pitch = rate of impulses.

Perceptual Processing:

• Bottom-Up: Start with sensory input.

• Top-Down: Use prior knowledge.

• Binding Problem: How brain combines features into a whole.

Perceptual Constancy: Objects look the same even when conditions change (shape, size, color).

Figure & Ground: Focused object = figure, background = ground.

Closure: Brain fills in gaps to perceive a whole.

Gestalt Laws:

• Similarity: Group similar things.

• Proximity: Group close things.

• Common Fate: Group things moving together.

Depth Cues:

• Binocular: Two eyes (retinal disparity, convergence).

• Monocular: One eye (linear perspective, texture gradient, interposition, etc.).

Perceptual Set: Expectations influence perception.