The need for Psychological Science • Common sense can not be relied on • Hindsight bias: Influenced by results in the past makes us poor predictors of what will happen • Overconfidence: The bias we believe we are right because it’s what we believe, 80% confidence with 40% accuracy • Perceiving Order in Random Events: We attempt to find sequence or pattern in events that are in random sequences. We construct order from them that is often untrue. Post-Truth World • 2017 the word of the year was: post-truth • Post-truth: People’s personal emotions and personal beliefs often override their acceptance of objective facts Truth Decay • Belief: The crime rate is rising. Every recent year, 7 in 10 adults told Gallup that there is more crime “than there was a year ago” (Swift, 2016). • Fact: For several decades, both violent and property crime rates have been falling. In 2015, the violent crime rate was less than half the 1990 rate (BJS, 2017; Statista, 2017). Influences for Post-Truth • False news • In 2016 US Election cycle, 6% of Twitter-enabled news consumption was not accurate (Grinberg et al., 2019) • Repetition • Powerful examples: “if it bleeds it leads” • Group identify and like-minded What can we do? The Scientific Method The Scientific Method • Theory • Hypotheses: Good theories leading to predictions • Operational Definitions: Precise and measurable The Scientific Method • Description: Objective and systematic measurement of behavior • Naturalistic observation • Survey: asking people to report their own behavior • Wording effects, Random sampling The Scientific Method • Correlation: How closely two variables are related The Scientific Method • Correlation: How closely two variables are related • Illusory correlation: If the relation is not clear, we may attempt to confirm that relation based on our own beliefs • Confirmation bias • Regression toward the mean: After an extreme result, things tend to return to their average level • Need steady state behavior for conclusions Correlation ≠ Causation • Two events may correlate, but does not mean that one event caused another Experimentation • Experiment: Identify cause and effect • Experimental group: Treatment group (IV -> DV) • Control group: No treatment group (no IV -> DV) • Relies on random assignment to either group Independent and Dependent Variables • Variable: anything that can vary • Independent variable: the variable is that manipulated, controlled, and applied • Dependent variable: the outcome variable, depends on exospore and effect of independent variable • Confounding variable: factors that influence a study’s results that are uncontrolled • Research design: most appropriate method to evaluate the question Placebo Effect • Treatment effect without receiving treatment simply because participants believed they were receiving treatment • Well documented but not necessarily well understood (Dollfus et al., 2016; Kirsch, 2010) • Double-blind procedure mitigates this effect Ethical factors within the Research Process • Study and protecting animals • Institutional animal care and use committee (IACUC) • Assent • Study and protecting humans • Institutional review board (IRB) • Informed consent and debrief • Scientific Integrity • Accurately reporting data (recall the necessity for humility) • E.g., 1998, Andrew Wakefield falsified data in the Lancet that the MMR vaccine caused autism A note about Statistics • Measures of central tendency • Mean: Arithmetic average • Median: Middle point • Mode: Most frequently observed score A note about Statistics • Measures of variation • Range: Gap between lowest and highest • Standard deviation: Standard for measuring how much scores differ from one another • Normal curve (Bell curve) Significant Differences • Null hypothesis: We first assume that there is no effect or differences • Statistical significance: When results are obtained that are as or more extreme if the null hypothesis is true