The Psychology Notes Headquarters

A null hypothesis is the default claim that nothing interesting is happening: no difference between groups, no relationship between variables, no effect of a treatment. Researchers do not set out to prove it. They set it up specifically so their data can argue against it. Working through actual null hypothesis examples from published psychology research makes this logic click...

Self handicapping psychology explains why people sometimes create their own obstacles before a big test, presentation, or performance, using those obstacles as a built-in excuse if things go wrong. It sounds counterproductive, and it is, but it also protects something people value even more than success: their sense of competence. Instead of risking a clear verdict on their a...

Psychological changes in adolescence are the shifts in emotion, cognition, identity, and social behavior that occur as the brain and body mature between roughly ages 10 and 19. These changes are driven by a mix of hormonal surges, brain restructuring, and new social pressures, and they show up as mood swings, a stronger drive for independence, more abstract thinking, and...

The frustration-aggression hypothesis, introduced by John Dollard, Neal Miller, and their colleagues at Yale in 1939, proposes that frustration — defined as the blocking of a goal-directed behavior — always leads to some form of aggression, and that aggression is always caused by frustration. Few ideas in social psychology sparked as much debate, inspired as much follow-up re...