PSY113_Chapter-1.pdf

1 Experimental Psychology and the Scientific Method CHAPTER OBJECTIVES Understand why we rely on scientific methods rather than common sense to explain behavior Learn the principles of the scientific method Learn the basic tools of psychological research Understand how...

1 Experimental Psychology and the Scientific Method CHAPTER OBJECTIVES Understand why we rely on scientific methods rather than common sense to explain behavior Learn the principles of the scientific method Learn the basic tools of psychological research Understand how “cause and effect” is established by experimentation Fundamentals of Psychological Science 1. Definition of Psychology: Psychology is the science of behavior. As psychologists, our understanding of behavior is based on scientific evidence accumulated through research. 2. Scientific Approach in Psychology: Psychological research relies on scientific methods, including: o Specifying conditions under which observations are made. o Observing behavior systematically. o Accepting or rejecting alternative explanations based on observed data. 3. Psychological Science: Research focused on the psychological processes underlying behavior is known as psychological science. 4. Meaning of Science: Origin of the Word: o "Science" comes from the Latin word scientia, meaning knowledge. Two Meanings of Science: o Content: The knowledge acquired, such as facts learned in psychology or chemistry. o Process: The systematic methods used to gather data, identify relationships, and offer explanations. 5. Aim of Psychological Science: The main aim is to understand the process of psychological science, including the methodology used to collect and evaluate psychological data. 6. Research Methods in Psychology: Methodology: The scientific techniques used to collect and evaluate psychological data. Application Across All Areas: o Perception: Data collection through formal laboratory experiments. o Attitudes and Social Behaviors: Data gathered in controlled laboratory conditions or through surveys and natural observations. o Human Development: Observations of children in laboratory or real-world settings. o Clinical Psychology: Data collection via psychological tests or observations during therapy sessions. 7. Evaluation of Data: Regardless of the data source (laboratory experiments, real-world settings, or therapy sessions), psychologists use scientific criteria to evaluate their findings. 2 The Need for Scientific Methodology in Psychology 1. Commonsense Psychology: Definition: The everyday, nonscientific data gathering that influences our expectations, beliefs, and behavior toward others. Examples: o Avoiding asking a favor from a roommate in a bad mood. o Dressing up for a job interview to make a good first impression. o Not inviting people who don’t get along to the same party. 2. Limitations of Commonsense Psychology: Inconsistent Data: o Commonsense psychology often relies on conflicting adages or beliefs (e.g., "absence makes the heart grow fonder" vs. "out of sight, out of mind"). o This can lead to uncertainty and anxiety, as seen in the example of a significant other going to Paris. Constraints on Data Collection: o Sources of Information: ▪ Commonsense beliefs are derived from personal experience and information learned from others, which can be unreliable. o Inferential Strategies: ▪ The conclusions drawn from commonsense data are often based on a small, biased sample of behaviors. Biases and Imperfections: o Commonsense beliefs are subject to biases that limit their accuracy and usefulness. o As a result, predictions and explanations based on commonsense psychology are often imperfect and unreliable. 3. Need for a Scientific Approach: Impartial Data Gathering: o Scientific methodology provides a systematic and unbiased way to collect and evaluate data, overcoming the limitations of commonsense psychology. Improving Predictions: o A scientific approach helps in making more accurate predictions and understanding behavior more reliably. Nonscientific Sources of Data in Psychology 1. Unreliable Sources of Psychological Information: Common Sources: o Friends, relatives, people in authority, media reports, books, and admired individuals often provide psychological information. Acceptance Without Question: o Information from these sources is typically accepted without critical examination, especially when it comes from people we like, respect, or admire. 2. Confirmation Bias: Definition: o The tendency to seek out and remember information that confirms our pre-existing beliefs while ignoring information that contradicts them. Example: 3 o Believing that the full moon causes psychotic behavior (lunacy) and only noticing instances when abnormal behavior coincides with a full moon, while ignoring all the times it doesn’t. 3. Influence of Myths, Superstitions, and Pop Psychology: Common Beliefs: o Belief in the power of crystals, horoscopes, knocking on wood, or fear of Friday the 13th. Scientific Validation: o Among these, only fear of Friday the 13th has some scientific documentation. 4. Influence of Certain Individuals: More Persuasive Sources: o Popular, attractive, high-status, seemingly expert, or highly confident individuals are more powerful sources of information. Influence on Behavior: o We often unknowingly accept information from these sources without realizing the actual reasons behind our persuasion. 5. Unawareness of Influences on Behavior: Example from Research: o Study by North, Hargreaves, and McKendrick (1999): ▪ French or German music played in a supermarket influenced the purchase of French or German wine, yet only 1 out of 44 people mentioned the music as a factor in their choice. ▪ Even when asked directly, only 6 out of 44 considered the music might have influenced their decision. 6. Errors in Commonsense Psychology: Over-Simplification: o The inferential strategies used in commonsense psychology are often too simple, leading to frequent errors in understanding cause and effect. Reliance on Personal Experience: o Relying solely on personal experiences for understanding behavior can lead to incorrect assumptions and predictions. Nonscientific Inference in Psychology 1. Trait Theorist Bias in Commonsense Psychology: Trait Assignation: o We often explain others' behavior by assigning traits (e.g., concluding Stacy is vain because she wears designer clothes). Overlooking Situational Factors: o There's a tendency to ignore situational data (e.g., Stacy's clothes are discounted because her mother designs them) in favor of trait-based explanations. 2. Accuracy of Trait-Based Predictions: Acquaintanceship Impact: o Our ability to accurately predict someone’s behavior based on traits improves with the length of acquaintanceship. Overestimation of Behavioral Consistency: o People tend to overestimate how consistently someone will act according to their traits across various situations, potentially by a factor of 10. 3. Research on Trait and Situational Predictors: Debate on Predictors: 4 o Psychologists have debated whether traits or situations are better predictors of behavior. Evidence suggests that both can be correct, depending on the context (traits for long-term behavior, situations for momentary behavior). 4. Stereotyping and Confirmation Bias: Stereotyping: o We often assign traits based on stereotypes (e.g., assuming Carol, a librarian, is serious because that’s part of the librarian stereotype). Confirmation Bias in Stereotypes: o Once a stereotype is formed, we tend to seek out behavior that confirms it (e.g., noticing Carol always has her nose in a book, reinforcing the stereotype). 5. Inferential Errors and Biases: Gambler’s Fallacy: o Misjudging the likelihood of events (e.g., believing a slot machine is "due" for a win after a long dry spell, despite each spin being independent and random). Overconfidence Bias: o We tend to be more confident in our judgments about behavior than is warranted, especially when we have more (even inaccurate) data. 6. Need for the Scientific Method: Human Information Processing Biases: o Biases are shortcuts the brain uses to manage vast amounts of information. While they often help us function, they are not always accurate. Scientific Method as a Solution: o To rely on conclusions and use them as general principles to predict behavior across various settings, we must proceed systematically and objectively—using the scientific method. Characteristics of Modern Science 1. The Scientific Mentality Assumption of Natural Order: Behavior follows a natural order and can be predicted, forming the basis of scientific inquiry. Determinism: The belief that behavior is caused by specific factors, which can be discovered through research. 2. Gathering Empirical Data Empirical Data: Information that is observable or experienced and can be verified or disproved through investigation. Systematic Observation: The method of collecting data in a structured and organized way, tracing back to Aristotle's work. Verification through Investigation: Systematic observation can lead to correct or incorrect conclusions, as demonstrated by Galileo's findings. 3. Seeking General Principles General Principles: Modern scientists seek to explain observations through theories or laws that apply universally. Laws vs. Theories: o Laws: Universal principles that apply to all situations (e.g., Kepler's laws). o Theories: Interim explanations that unify scientific facts and predict new behaviors. Progress Through Better Theories: According to Sir Karl Popper, science advances by developing theories with greater explanatory power. 4. Good Thinking 5 Systematic and Rational Approach: Data collection and interpretation should be objective and logical. Principle of Parsimony (Occam's Razor): The simplest explanation, requiring the fewest assumptions, is preferred. Example: Crandall's study on bulimia, where social contagion was found to be the most parsimonious explanation. 5. Self-Correction Scientific Uncertainty: Science accepts that conclusions may change with new information, emphasizing the "weight-of-evidence" approach. Example: Transition from social learning theory to cognitive priming theory in explaining the link between media violence and aggressive behavior. 6. Publicizing Results Scientific Communication: Modern science relies on the public exchange of information through conferences and journals. Continuous Exchange: This allows for the incorporation of recent findings and reduces wasted efforts in research. 7. Replication Importance of Replication: Scientific findings should be repeatable under the same conditions by other researchers. Replication in Psychology: Replication builds confidence in research findings and helps validate the results. Example: The case of cold fusion, where worldwide attempts failed to replicate the original findings. The Objectives of Psychological Science This module will introduce the four primary objectives of psychological science: description, prediction, explanation, and control. Understanding these objectives will help you grasp the fundamental purposes of research in psychology and how different research methods contribute to these goals. 1. Description Definition: Description is the systematic and unbiased account of the observed characteristics of behaviors. Purpose: It allows researchers to gain a better understanding of behaviors by providing detailed information on what a behavior is like. Methods: Common descriptive research methods include: o Case Studies: Observations of a single individual to infer the origins of psychological disorders, developmental processes, etc. o Field Studies: Observational studies of groups in real-life settings, often used to study social and cultural experiences. o Surveys and Interviews: Used to gather descriptive information such as attitudes and opinions. 2. Prediction 6 Definition: Prediction refers to the ability to foresee when certain behaviors are likely to occur based on the identification of conditions associated with those behaviors. Purpose: Helps in predicting behaviors ahead of time by understanding their associations with other events or conditions. Methods: o Correlational Designs: Statistical relationships between different events or behaviors (e.g., the link between obesity and type 2 diabetes). o Quasi-Experimental Designs: Comparisons among groups to make predictions (e.g., predicting personality traits based on music preferences). 3. Explanation Definition: Explanation involves understanding the causes of behaviors by identifying the conditions that reliably produce them. Purpose: It allows researchers to infer cause-and-effect relationships by manipulating variables and controlling for other factors. Methods: o Experimental Designs: Systematic manipulation of variables to observe effects on behavior, which allows for inferences about causality. 4. Control Definition: Control is the application of psychological knowledge to effect change or improve behavior. Purpose: Though often not the primary intent of research, control aims to apply findings to real- world problems (e.g., improving therapies, enhancing employee morale). Methods: o Applied Research: Research designed to solve real-world problems (e.g., testing the effectiveness of therapies). o Basic Research: Research aimed at testing theories or explaining psychological phenomena, which may later be applied to practical issues. Case Study: Applied vs. Basic Research Applied Research Example: A clinical study testing whether cognitive-behavioral therapy is more effective than other therapies in reducing grief. Basic Research Example: Research exploring the psychological mechanisms behind childhood violence, with long-term goals of influencing public policy. The Scientific Method: Tools of Psychological Science This module provides an introduction to the key tools of the scientific method in psychological research: observation, measurement, and experimentation. Understanding these tools is essential for conducting rigorous and ethical research in psychology. 1. Observation 7 Definition: Observation is the systematic noting and recording of events. Scope: Only observable events can be studied scientifically. However, internal processes such as thinking and feeling can be studied by developing observable signs (e.g., response times, mood questionnaires). Systematic Approach: Observations must be consistent and objective, using the same system for each observation. Objectivity ensures that different observers can record the same events consistently. Example: In research, mood cannot be directly observed, so researchers use mood questionnaires to gather data on participants’ emotional states. 2. Measurement Definition: Measurement is the assignment of numerical values to objects, events, or their characteristics according to conventional rules. Importance: Standardized measurements are essential for comparing behaviors and ensuring consistency across different conditions in a study. Application in Research: Researchers assign numerical values to behaviors or characteristics to quantify them, allowing for statistical analysis. The consistency of measurements is critical to ensure that comparisons are valid. Example: In a study measuring mood, researchers might use a numbered scale to quantify levels of anger or depression, ensuring the same scale is used consistently across all participants. 3. Experimentation Definition: Experimentation involves systematically manipulating aspects of a setting to test a hypothesis about specific behavioral outcomes. Key Requirements: 1. Manipulation: Researchers must have procedures for manipulating the setting. 2. Observability: The predicted outcomes must be observable. 3. Measurability: The outcomes must be measurable. Objectivity: Experimentation must be objective, avoiding bias or influencing participants to respond in a desired way. Ethical Considerations: Not all experiments are ethically permissible. Researchers must avoid unethical practices, such as causing harm to participants or violating their privacy. Example: A researcher testing the effects of stress on mood might manipulate the environment to create stressful conditions, observe participants' mood changes, and measure the results using standardized tools. Case Study: Application of Tools in Research Observation Example: Researchers observe participants’ moods using a mood questionnaire. Measurement Example: Participants’ responses are quantified using a numbered scale to measure levels of depression or anger. 8 Experimentation Example: The researcher manipulates the environment to induce stress, then measures how mood changes as a result. Understanding Scientific Explanation in Psychological Science 1. Introduction to Scientific Explanation in Psychology Scientific Explanation: In psychology, explaining behavior scientifically means identifying the antecedent conditions (circumstances that precede an event or behavior) that lead to a particular outcome. 2. Identifying Antecedent Conditions Antecedent Conditions: These are the factors that occur before the behavior or event we want to explain. Example: In Baron’s experiment, different concentrations of negative ions (antecedent conditions) were used to explain changes in mood (the behavior). 3. Comparing Treatment Conditions Treatment Conditions: In experiments, specific sets of antecedent conditions are created, called treatments. By comparing different treatment conditions, we can systematically and scientifically test explanations of behavior. o Example: Participants are exposed to high or low concentrations of negative ions to see how these conditions affect their mood. Key Point: The word "treatment" doesn't always mean an active intervention; it can simply mean exposing subjects to different antecedent conditions. 4. The Psychology Experiment Experiment Definition: A psychology experiment is a controlled procedure where at least two different treatment conditions are applied to subjects, and their behaviors are measured and compared to test a hypothesis. o Control: Key to ensuring valid results by controlling for factors other than the treatment conditions. o Random Assignment: Subjects are randomly assigned to different treatment conditions to avoid systematic differences between groups. o Design Types: ▪ Between-Subjects Design: Each subject receives only one treatment condition. ▪ Within-Subjects Design: Each subject receives all treatment conditions, but this can sometimes lead to issues like carryover effects. 5. Establishing Cause and Effect Cause-and-Effect Relationship: Through experiments, psychologists can infer a cause-and-effect relationship between antecedent conditions and behaviors. o Temporal Relationship: The cause (treatment condition) precedes the effect (behavior). This is crucial in establishing causality. o Control: By controlling for other potential explanations, experiments bring us closer to establishing true cause-and-effect relationships. 9 6. Necessary vs. Sufficient Conditions Necessary Condition: Something that must be present for an event to occur. (e.g., Fuel is necessary for a snowmobile to run.) Sufficient Condition: Something that can cause an event but is not the only way the event can occur. (e.g., Being in a good mood is sufficient to increase helpfulness but not necessary.) o Example: Cutting carbohydrates may be sufficient for weight loss, but it’s not necessary—other methods like increasing activity can also lead to weight loss. 7. Conclusion: The Importance of Control in Psychological Experiments Control is Critical: To draw valid conclusions, all other explanations should be controlled or ruled out. This is achieved through random assignment, consistent treatment presentation, and keeping the environment and measurement tools constant. Practical Approach to Causality: In psychological science, researchers often focus on identifying sufficient conditions for behavior rather than seeking the ultimate cause.