Unit 1: How Are Behaviour and Mental Processes Shaped?
The developing brain and nervous system
Unit 1 frames psychology as a biological and developmental science. You must be able to describe the neuron (dendrites, soma, axon, myelin, axon terminals, synapse) and explain how neurotransmitters cross the synaptic gap, then distinguish excitatory from inhibitory effects. Know the divisions of the nervous system: central (brain, spinal cord) versus peripheral, with the peripheral split into somatic and autonomic, and the autonomic into sympathetic (arousal, fight-or-flight) and parasympathetic (calming, homeostasis). Be able to trace a simple reflex arc.
Brain development includes synaptogenesis, synaptic pruning, and myelination, and the idea that experience shapes neural pathways (plasticity). Link this to sensitive periods and to Piaget's stages of cognitive development: sensorimotor, preoperational, concrete operational, formal operational, with key features such as object permanence, egocentrism, and conservation. Understand classical conditioning (Pavlov: neutral stimulus becomes conditioned stimulus; acquisition, extinction, spontaneous recovery) and operant conditioning (reinforcement and punishment, positive and negative).
Traps to watch
- Negative reinforcement is not punishment. Negative means a stimulus is removed; reinforcement means the behaviour increases.
- Sympathetic and parasympathetic are both autonomic; neither is under conscious control in the way skeletal muscle is.
- Pruning is not loss of function; it increases efficiency.
- Egocentrism is difficulty taking another's perspective, not selfishness.
Rule of thumb
For any conditioning scenario, ask two questions in order: (1) Did the behaviour increase or decrease? (2) Was something added or removed? Increase + added = positive reinforcement; increase + removed = negative reinforcement; decrease + added = positive punishment; decrease + removed = negative punishment.
Worked example
A student studies to avoid being grounded. Grounding is removed when study occurs and studying increases, so this is negative reinforcement, not punishment.