I CHAPTER 2 STUDY GUIDE METHODS IN PSYCHOLOGY Empiricism How to Know Stuff A Originally there were two kinds of Greek doctors Dogmatists and Empiricists 1 Dogmatists attempted to treat illnesses by developing theories about the body s functions a Dogmatism the tendency for people to cling to their assumptions 2 Empiricists attempted to treat illnesses by understanding the illness through the observation of sick people a Empiricism the belief that accurate knowledge of the world requires observation 3 Only in the last 300 years have people trusted observation over elders laying the foundation for modern science B The Scientific Method 1 The Scientific Method is a set of principles about the appropriate 2 Empiricism is at the heart of the scientific method relationship between ideas and evidence a Theory a hypothetical explanation of a natural phenomenon i Begins with the simplest theory referred to as the rule of parsimony b Hypothesis a falsifiable prediction made by a theory 3 Results of these tests can disprove theories but cannot prove them C The Art of Looking 1 Empirical method a set of rules and techniques for observation on a Method in science typically refers to technologies that enhance the powers of the senses i Biologists use microscopes astronomers use telescopes and so Psychology s empirical methods are among the most sophisticated in modern science because people are especially difficult to study due to their i Complexity ii Variability iii Reactivity b II Observation Discovering What People Do A To observe means to use one s senses to learn about the properties of an event 1 Observing something means using your senses to learn about the thing s properties a Casual observations are notoriously unstable they can t tell you about many of the properties of something you might be interested in 2 To know and understand the properties you must measure them B Measurement 1 Must first define the property to measure then find a way to detect it 2 Defining and Detecting concrete condition that can be measured a Operational Definition description of property in terms of a Example The operational definition of a second the duration of 9 192 631 770 cycles of microwave light absorbed or emitted by the hyperfine transition of cesium 133 atoms in their ground state undisturbed by external fields roughly takes six seconds just to say i b Measure device that can detect the events to which an operational definition refers i ii Electromyograph EMG a device that measures muscle Cesium clock can actually count a second contractions under the surface of a person s skin 3 Validity Reliability and Power conceptually related a Validity the extent to which a measurement and a property are b Reliability the tendency for a measure to produce the same measurement whenever it is used to measure the same thing c Power the ability of a measure to detect the concrete conditions specified in the operational definition 4 Demand Characteristics ii a People are often trying to behave as they think they should behave i Demand Characteristics those aspects of an observational setting that cause people to behave as they think they should a Example Do you think these jeans make me look fat Naturalistic Observation a technique for gathering scientific knowledge by unobtrusively observing people in their natural environments a Example Biggest groups leave smallest tips in restaurants b Two reasons why naturalistic observation doesn t solve 1 Some of the things that psychologists want to observe do not occur naturally 2 Some of the things that psychologists want to observe can only be gathered from direct interaction with a person demand characteristic problems iii Techniques for avoiding demand characteristics a Allow subjects to respond anonymously b Measure behaviors that are not susceptible to demand characteristics 1 Example Pupil dilation in response to excitement c Retain lack of relationship information between demand and behavior i e keep the participant blind to the purpose of the study 1 Sometimes requires a cover story or misleading explanation 2 Might also require filler items or pointless measures that are meant to mask the true purpose of the observation 5 Observer Bias a Expectations can influence observations i Even well intentioned observers may make adjustments in favor of an expectation b Expectations can influence reality i Reactions to an expectation can have an impact on the participant in real time c Double Blind an observation whose true purpose is hidden from the researcher as well as from the participant i Scoring responses without knowing what is supposed to happen removes potential for bias and is easy to do if a computer can do the scoring C Descriptions way to make sense of large page of numbers 1 Graphic Representations a Frequency Distributions graphic representations of the measurements of a sample that are arranged by the number of times each measurement was observed b Normal Distribution a frequency distribution in which most 2 Descriptive Statistics brief summary statements that capture the measurements are concentrated around the middle essential information from a frequency distribution a Descriptions of Central Tendency summary statements about the value of the measurements that lie near the center or midpoint of a frequency distribution 1 Mode the most frequent measurement in a frequency 2 Mean the average of the measurements in a frequency distribution distribution Median the middle measurement in a frequency distribution or the value that is greater than or equal to the values of half the measurements and less than or equal to half of the values of the measurements 3 b Descriptions of Variability 1 Range the numerical difference between the smallest and largest measurements in a frequency distribution Standard Deviation a statistic that describes the average difference between the measurements in a frequency distribution and the mean of that distribution 2 a In other words how far are the measurements from the center of the distribution III Explanation Discovering Why People Do What They Do A Although the careful measurement of properties is important the ultimate goal of scientific research is to discover the causal relationships between properties 1 Measurement can tell how much of a property exists but cannot tell whether two properties are related or whether relationship is causal B Correlation the co relationship or pattern of covariation between two variables