Experimental Psychology Chapter 1 PDF

Experimental Psychology and the Scientific Method Deborah P. Cuyat, RPm, CHRA Topics Covered THE NEED FOR SCIENTIFIC METHODOLOGY THE CHARACTERISTICS OF MODERN SCIENCE THE OBJECTIVES OF PSYCHOLOGICAL SCIENCE THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE SCIENTIFIC EXPLANATION IN PSYCHOL...

Experimental Psychology and the Scientific Method Deborah P. Cuyat, RPm, CHRA Topics Covered THE NEED FOR SCIENTIFIC METHODOLOGY THE CHARACTERISTICS OF MODERN SCIENCE THE OBJECTIVES OF PSYCHOLOGICAL SCIENCE THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE FROM PSEUDOSCIENCE TO PSYCHOLOGICAL SCIENCE 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 Psychology is the science of behavior. As psychologists, we take a scientific approach to understanding behavior, and our knowledge about psychological processes is based on scientific evidence accumulated through research. The word science comes from the Latin word scientia, which simply means knowledge. As the word is used today, however, it has two meanings content and process. The content of science is what we know, such as the facts we learn in our psychology or chemistry courses. But science is also a process—that is, an activity that includes the systematic ways in which we go about gathering data, noting relationships, and offering explanations. THE NEED FOR SCIENTIFIC METHODOLOGY The kind of everyday, nonscientific data gathering that shapes our expectations and beliefs and directs our behavior toward others has been called commonsense psychology Nonscientific Sources of Data Very often, the data we gather as commonsense psychologists come from sources that seem credible and trustworthy—friends and relatives, people in authority, people we admire, reports from the media, books we have read, and so forth—but, actually, these sources are not always very good ones for obtaining valid information about behavior. Once we believe we know something, we tend to overlook instances that might disconfirm our beliefs, and we seek, instead, confirmatory instances of behavior. This has been termed the confirmation bias. Nonscientific Sources of Data If you believe that the full moon brings out psychotic behavior (the word lunacy comes from the Latin word for “moon”), you will notice and remember instances when people acted abnormally while the moon was full, and you will ignore the many, many more instances in which no unusual behavior occurred. Nonscientific Sources of Data Research has shown that we are more likely to believe information if it comes from certain kinds of individuals: People who are popular, attractive, high in status, seemingly expert, or who appear highly confident are more powerful sources of information than others are. But other people are not our sole source of data about psychological processes. The Power of Negative Thinking Friday the 13th has a mythical history of being unlucky, and if Friday falls on the 13th of the month, the superstition often comes to mind (or someone reminds us!). Do you feel a moment of anxiety when you realize it’s Friday the 13th? Have you ever wondered whether it is really unlucky? Apparently it is, but probably not because of any dark and powerful, unseen force that exerts its will upon us. A study conducted in West Sussex in Great Britain and reported in the British Medical Journal (Scanlon, Luben, Scanlon, & Singleton, 1993) found that Friday the 13th did appear to be an unlucky day for drivers. When researchers compared each Friday the 13th with each Friday the 6th since 1989, looking at the number of emergency room visits from automobile accidents, more accident victims (as many as 52% more) were treated on Friday the 13th even though fewer cars were driven that day. According to the researchers, the higher accident rate for Friday the 13th was probably caused by increased trepidation about the date: Anxiety caused reduced attention to driving, and more accidents occurred. Whether their reason is the correct one or not, it makes sense to be extra cautious if you are driving that day because other drivers might be more anxious and accident-prone than usual. An expert source like Einstein would be highly persuasive. Nonscientific Inference One of the first and most important kinds of data we collect about others comes in the form of traits we assign to them. All commonsense psychologists are trait theorists—at least when it comes to explaining the behavior of others. We tend to miss or ignore important information about the situation (for instance, that Stacy’s mother designs for the manufacturer and gets Stacy’s clothes for almost nothing). Our ability to make accurate predictions about someone’s traits increases with the length of acquaintanceship. We are generally more accurate when we know someone well than when we judge a stranger (Colvin & Funder, 1991). But, not always (see Box 1.2). Nonscientific Inference Compounding our inferential shortcomings is a phenomenon known as the overconfidence bias. Our predictions, guesses, and explanations tend to feel much more correct than they actually are, and the more data we have available (accurate or not), the more confidence we have in our judgments about behavior (Dunning, Griffin, Milojkovic, & Ross, 1990). Nonscientific Inference These and many other inferential biases exist in human information processing. They are believed to be the brain’s way of coping with an immense volume of information. They are shortcuts, and most of the time, they allow us to function well enough, but they are not always accurate. The steps scientists take to gather and verify information, answer questions, explain relationships, and communicate this information to others are known as the scientific method. THE CHARACTERISTICS OF MODERN SCIENCE The Scientific Mentality The psychologist’s goal of prediction rests on a simple, but important, assumption: Behavior must follow a natural order; therefore, it can be predicted. This elementary assumption lies at the heart of what Alfred North Whitehead (1861–1947) called the “scientific mentality.” THE CHARACTERISTICS OF MODERN SCIENCE The Scientific Whitehead was a philosopher of scienceMentality who traced the development of science in his now classic book Science and the Modern World (1925). He postulated that faith in an organized universe is essential to science. If no inherent order existed, there would be no point in looking for one and no need to develop methods for doing so. Research psychologists share the belief that there are specifiable (although not necessarily simple or obvious) causes for the way people behave and that these causes can be discovered through research. This belief is called determinism. Gathering Empirical Data Whitehead traced the beginnings of modern science to the works of the Greek philosopher, Aristotle (384–322 BC). Like contemporary scientists, Aristotle assumed that order exists in the universe, and he set about describing that order in a systematic way by collecting empirical data—that is, data that are observable or experienced. Aristotle advocated systematic observation and careful classification of naturally occurring events. From his own systematic observations, Aristotle argued that heavy objects fall faster than light objects because their “natural” place is down. Another important characteristic of empirical data, however, is that they can be verified or disproved through investigation. Gathering Empirical Data Later investigation of falling objects by Galileo (1564–1642) led to the inescapable conclusion that if we set up the proper testing conditions (in this case testing objects in a vacuum), light objects will fall just as fast as heavy ones. Thus, gathering empirical data in a systematic and orderly way, as Aristotle did, is preferable to commonsense data collection, but it still cannot guarantee that the correct conclusions will be reached. Seeking General Modern scientists go beyond cataloging observations to proposing Principles general principles—laws or theories—that will explain them. We could observe endless pieces of data, adding to the content of science, but our observations would be of limited use without general principles to structure them. When these principles have the generality to apply to all situations, they are called laws. For example, astronomer Tycho Brahe (1546–1601) painstakingly gathered observations of the stars for nearly a lifetime. But Johannes Kepler (1571–1630) made these observations useful by explaining them through a system of equations now known as Kepler’s laws. Seeking General Typically, we do not have enough information to state a general law, Principles but we advance understanding by devising and testing an interim explanation, commonly called a theory. Theories pull together, or unify, diverse sets of scientific facts into an organizing scheme, such as a general principle or set of rules, that can be used to predict new examples of behavior. Seeking General Theories can explain many, but not all, instances of a situation or Principles behavior—the more a theory can explain, the better it is. Sir Karl Popper (1902–1994), a modern philosopher of science, wrote that science progresses only through progressively better theories (Popper, 1963). Old theories are replaced by new theories with greater explanatory power. Laws are seldom determined outside the physical sciences, so the behavioral sciences like psychology largely progress by developing better and better theories. Good Thinking A central feature of the scientific method is good thinking. Our approach to the collection and interpretation of data should be systematic, objective, and rational. The scientist avoids letting private beliefs or expectations influence observations or conclusions. Good thinking includes being open to new ideas even when they contradict our prior beliefs or attitudes. Good thinking also follows the rules of logic. Good Thinking The principle of parsimony, sometimes called Occam’s razor. William of Occam was a 14th-century philosopher who cautioned us to stick to a basic premise: Entities should not be multiplied without necessity. What Occam had in mind was simplicity, precision, and clarity of thought. We must avoid making unnecessary assumptions to support an argument or explanation. When two explanations are equally defensible, the simplest explanation is preferred until it is ruled out by conflicting data. Self-Correction Changes in scientific explanations and theories are an extremely important part of scientific progress. Experience favors a “weight-of- evidence” approach: The more evidence that accumulates to support a particular explanation or theory, the more confidence we have that the theory is correct. According to Popper, old explanations often give way simply because the weight of supporting evidence tips the scales in favor of a different scientific explanation. Self-Correction For example, for more than 30 years, the link between media violence and aggressive behavior was explained by social learning theory. This theory asserted that people would perform the same kinds of aggressive behaviors they had observed in films or on television by learning to imitate the aggressive behavior of the media models. At present, cognitive priming theory is more commonly used to explain these effects. The newer theory posits that observing violence trigger cognitive representations of aggressive behavior stored in memory in our own cognitive schemas. Publicizing Results Because of its dynamic nature, modern science has become a highly public activity. Scientists meet frequently through professional and special interest groups and attend professional conferences to exchange information about their current work. The number of scientific papers published each year in scientific journals is growing, and new journals are constantly being added in specialized disciplines. This continuous exchange of information is vital to the scientific process. It would do little good for scientists to work in isolation. The opportunity to incorporate the most recent findings of others would be missed, and there would be a lot of wasted effort as researchers duplicated failures as well as successes. Replication We should be able to repeat our procedures and get the same results again if we have gathered data objectively and if we have followed good thinking. Findings that are obtainable by only one researcher have very limited scientific value. For example, people sometimes report dreams that seem to predict the future. A woman dreams of a stranger and meets him the following day; a man dreams of a car accident and then hears of a friend’s fatal crash. Have these people seen into the future through their dreams? THE OBJECTIVES OF PSYCHOLOGICAL There are four major objectives of research conducted in psychology: SCIENCE description, prediction, explanation, and control. Description The initial step toward understanding any phenomenon, whether it is the path of the stars in the heavens or the complexities of human and animal behaviors. When we define description in psychological science, we are referring to a systematic and unbiased account of the observed characteristics of behaviors. Prediction The second objective, refers to the capacity for knowing in advance when certain behaviors would be expected to occur—to be able to predict them ahead of time—because we have identified other conditions with which the behaviors are linked or associated. We know that the death of a grandparent, for example, is associated with grief, and we can predict that a person will feel grief if a grandparent has died recently. Thus, prediction is useful for psychologists, both researchers and clinicians. Explanation The third objective, goes a step further. When we have explained a behavior, we also understand what causes it to occur. Explanation includes knowledge of the conditions that reliably reproduce the occurrence of a behavior. To explain a behavior, we have to use an experimental research design in which we systematically manipulate aspects of the setting with the intention of producing the specific behavior. Control The fourth objective, refers to the application of what has been learned about behavior. Once a behavior has been explained through experimentation, it may be possible to use that knowledge to effect change or improve behavior. Control is rarely the intent of experimentation, but some research is conducted with the intent of producing behavioral change along with increasing knowledge. Research that is designed to solve real-world problems (like helping patients to deal with grief or improving employee morale) is known as applied research. In contrast, research designed to test theories or to explain psychological phenomena in humans and animals is called basic research. It is often many years before results of basic research are translated into practical applications, but there is growing interest in bringing the two together. THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE The first tool, observation, is the systematic noting and recording of events. Only events that are observable can be studied scientifically. Observation THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE Measurement is the assignment of numerical values to objects or events or their characteristics according to conventional rules. When Measurement we do research, we assign numbers to different sizes, quantities, or qualities of the events under observation. THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE Experimentation is a process undertaken to test a hypothesis that particular behavioral events will occur reliably in certain, specifiable Experimentation situations. When we experiment, we systematically manipulate aspects of a setting to verify our predictions about observable behavior under specific conditions. Experimentation is not always possible. To do an experiment, our predictions must be testable. THE SCIENTIFIC METHOD: TOOLS OF PSYCHOLOGICAL SCIENCE Three minimum requirements must be met: First, we must have procedures for manipulating the setting. Second, the predicted Experimentation outcome must be observable. Third, we must be able to measure the outcome. SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE Identifying Antecedent In a scientific context, explanation means specifying the antecedent conditions of an event or behavior. Antecedent conditions, or Conditions antecedents, are the circumstances that come before the event or behavior that we want to explain. SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE Comparing Treatment In the psychology experiment, we create specific sets of antecedent conditions that we call treatments. We compare different treatment conditions Conditions so that we can test our explanations of behaviors systematically and scientifically. The word treatment, as used in experimentation, does not necessarily mean that we must actively do something to “treat” each subject (although it can mean this). Rather, it means that we are treating subjects differently when we expose them to different sets of antecedents. SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE A psychology experiment is a controlled procedure in which at least two different treatment conditions are applied to subjects. The subjects’ behaviors The Psychology are then measured and compared to test a hypothesis about the effects of Experiment those treatments on behavior. Note that we must have at least two different treatments so that we can compare behavior under varied conditions and observe the way behavior changes as the treatment conditions change. Note also that the procedures in the psychology experiment are carefully controlled so that we can be sure we are measuring what we intend to measure. For this reason, characteristics of subjects receiving different treatments are also controlled by special techniques like random assignment of subjects to different treatment conditions SCIENTIFIC EXPLANATION IN PSYCHOLOGICAL SCIENCE An experimental design in which subjects receive only one kind of treatment is called a between-subjects design. The Psychology Experiment Another way in which systematic differences in subjects might be ruled out is to present all treatments to each subject and measure the effect of each treatment after it is presented. Then, we could ascertain whether different treatments produced different effects. This experimental design is called a within-subjects design. Control is most often achieved by (1) random assignment of subjects to different treatment conditions (or sometimes by using a within-subjects design), (2) presenting a treatment condition in an identical manner to all subjects, and (3) keeping the environment, the procedures, and the measuring instruments constant for all subjects in the experiment so that the treatment conditions are the only things that are allowed to change. In this way can we be reasonably certain that changes in the treatments are the cause of observed differences in behavior. Establishing Cause and The greatest value of the psychology experiment is that, within the Effect experiment, we can infer a cause-and-effect relationship between the antecedent conditions and the subjects’ behaviors. If the XYZ set of antecedents always leads to a particular behavior, whereas other treatments do not, we can infer that XYZ causes the behavior. The type of cause-and-effect relationship we establish through experiments is called a temporal relationship, because a time difference occurs in the relationship. The treatment conditions come before the behavior, or, stated somewhat differently, the cause precedes the effect. FROM PSEUDOSCIENCE TO PSYCHOLOGICAL SCIENCE Psychology as an experimental science did not emerge until the late 1800s. Wilhelm Wundt (1832–1926), is generally credited with being the first experimental psychologist, and the birth of psychological science is usually dated from the opening of his laboratory in Leipzig, Germany, in 1879. There Wundt employed the tools of the scientific method (observation, measurement, and experimentation) to study human sensory experience. He made great gains in the precise measurement of sensory phenomena by using scientific instruments to calculate how long it took individuals to complete different kinds of sensory and perceptual tasks. As Wundt’s fame quickly grew, students from all over the world came to Leipzig to work in his laboratory. One of his first laboratory students was the American psychologist G. Stanley Hall. Hall went on to open the first psychology laboratory in the United States in 1883 at Johns Hopkins University. As in Europe, early academic psychology in the United States found its home in departments of philosophy under the rubric of mental philosophy. Mental philosophy included the study of consciousness and mental processes and was based on the premise that the human mind begins as a blank slate, gaining knowledge of the world through sensory experiences. Mental philosophers were primarily engaged in the study of the five senses through introspection and observation of their own mental processes and observing those of others. Despite their methodological and philosophical differences, the mental philosophers and the experimental psychologists found a common adversary in the “pop psychology” of the time. Pseudoscientific practices were very popular during the 1800s, particularly phrenology, physiognomy, mesmerism, and spiritualism (Benjamin, 2007). (The term pseudoscience—pseudo is Greek for “false”— characterizes any field of study that gives the appearance of being scientific but has no true scientific basis and has not been confirmed using the scientific method. Pseudoscientific Remedies: Phrenology, Physiognomy, Mesmerism, and The practice of phrenology involved assessing traits and dispositions by measuring the size and location of bumps on the skull. Individual traits, called Spiritualism “faculties,” were believed to reside in specific areas in the brain. Overuse of faculties was believed to result in corresponding bumps on the skull, whereas underuse produced cavities or dents. Phrenology clients were counseled to develop underused positive faculties (like benevolence) and to curb overused negative faculties (like destructiveness). Physiognomy involved using facial features, particularly the appearance of the eyes, nose, chin, and forehead, to evaluate traits, mental capacity, and skills. An arch in the upper part of the nose, for example, was believed to indicate fear and voluptuousness. Kindness was indicated in the uppermost part of the middle forehead. Unfortunately, physiognomy also promoted racial stereotypes and, for a time, even influenced criminal profiling and employee selection. The pseudoscience of mesmerism was invented by an Austrian physician, Franz Mesmer (1734–1815). Mesmer believed that fluids in the body ebbed and flowed by magnetic principles and that both physical and mental illness could be cured by realigning these fluids using magnets, electrodes, or his hands passed across the patient’s body. Mesmer later opened a lucrative clinical practice in Paris and produced a few spectacular “cures.” In 1784, King Louis XVI appointed a commission (led by Benjamin Franklin) to investigate Mesmer’s claims. The commission found no evidence for magnetic forces in body fluids, but mesmerism continued and spread to the United States in the 1830’s. In hindsight, it appears that Mesmer and his trainees were most likely inducing a hypnotic state and planting suggestions in the minds of hypnotized patients— and sometimes they worked. Spiritualism involved purported contact with ghosts and spirits of the dead. Acting as mediums, spiritualists held séances in which they claimed to speak with people who had died and provided psychological advice to the relatives of the departed who paid for these services. Even though spiritualism depended on a belief in an afterlife, it was strongly opposed by organized religions. Spiritualism was particularly strong just after the Civil War, when many lives were lost, and enjoyed a brief popularity in 1917–1918 following an influenza epidemic and World War I. Thank “Never discourage anyone…who you! continually makes progress, no matter how slow.” - Plato Resource Page https://drive.google.com/file/d/ 0B6sx2mPARK9EejQyVjlHZTVSMUU/ preview?resourcekey=0-D-- HQ4UUK5YhJsYkVCmSuQ