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Chapter 2

Chapter 2 PSYA01 TEXTBOOK NOTES.docx

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Steve Joordens

Chapter 2 – PSYA01 TEXTBOOK NOTES - Methods of psychology are meant to answer two basic questions : What do people do and why do they do it? - The first question is answered by observing and measuring and the second question is answered by looking for relationships between the things they measure Empiricism: How to Know Stuff: - When ancient Greeks got sick they would either go to a dogmatist or a empiricist - A dogmatist thought the best way to understand illness was to develop theories about the body’s function - A empiricist thought that the best way to understand illness was to observe sick people - Today we use dogmatism  to describe the tendency for people to cling to their assumptions - We use the word empiricism  to describe the belief that accurate knowledge can be acquired through observation The Scientific Method: - Empiricism is the essential element of the scientific method  which is a set of principles about the appropriate relationship b/w ideas and evidence - Scientific method suggests that when we have an idea about the world (ex. where the moon came from) we should gather empirical evidence relevant to that idea and then modify the idea to fit with the evidence - An idea of this kind is referred to as a theory  hypothetical explanation of a natural phenomenon - Ex. the moon was formed when a small planet collided with the Earth (explanation of how some things in the natural world works) - When scientists set out to develop a theory they start with the simplest one and refer to this as the rule of parsimony  start with the simplest theory possible and thennn make the theory more complicated only if we must Theories: - Theories are ideas about how and why things work the way they do - Most theories make predictions about what we should and should not be able to observe in the world - Ex. if bats really do navigate by making sounds and listening for echoes, then we should observe that deaf bats cant navigate (hypothesizing) - Hypothesis  falsifiable prediction made by a theory - Some theories such as “god created the universe” do not specify what we should or should no observe if they are true and thus no observation can falsify them - If theories cannot give rise to a hypothesis then they cannot be the subject of scientific investigation Why can’t evidence ever prove a theory right? - Two men argued about whether horses ever lift all four hooves at the same time - Eventually one man (Muybridge) took pictures and found that they do but why couldn’t they tell before then just by watching the horses gallop? - As wonderful as eyes may be there are a lot of things they cannot see and a lot of things they see incorrectly - We cant see germs but they are very real. The Earth looks flat but it is very round - We have to do more than just look if we want to know the truth about the world - Empiricism is the right approach but to do it properly required an empirical method  which is a set of rules that techniquies for observation What three things make people difficult to study? - in many sciences, the word method  refers primarily to technologies that enhance the powers of the senses (ex. biologists use telescopes to see what the naked eye cannot) - human behavior is easy to observe but the psychological methods used are amongst the most sophisticated in all of modern science - it’s difficult to study people: 1) COMPLEXITY: scientists can barely begin to say how the 500 million interconnected neurons that constitute the brain give rise to the thoughts, feelings and actions that are psychology’s core concerns 2) VARIABILITY: people are as varied as their fingerprints. No two individuals ever do, say, think or feel exactly the same thing under exactly the saem circumstances which means that when you’ve seen one, you’ve most definitely not seen them all 3) REACTIVITY: people often think, feel and act one way when they are being observed and a different way when they are not. When people know they are being studied, they don’t always behave as they otherwise would - complexity, variability and reactivity presents a major challenge to the scientific study of their behavior but psychologists have developed two kinds of methods that are designed to meet these challenged: 1) methods of observation  allows them to determine what people do 2) methods of explanation  allows them to determine why people do it Observation: Discovering What People Do: - Observe  means to use ones senses to learn about the properties of an event or an object - Informal observation such as observing a red able as round, red, etc is fine for buying fruit but not for doing science - Casual observations are notoriously unstable and cant tell us about all the properties that might interest us (you will never be able to tell how crunchy the apple is just by looking) Measurement What two things does measurement require? 1) define the property we wish to measure 2) find a way to detect it Defining and Detecting: - every unit of time has an operational definition  a description of a property in concrete measureable terms - a measure  is a device that can detect the condition to which an operational definition refers - ex. if we wanted to measure a persons happiness we would have to start by developing an operational definition of that property by specifying some concrete measureable even that indicates it (frequency with which a person smiles and then detect those smiles with an electromyograph) - electromyograph (EMG)  a device that measures muscle contractions under the surface of a persons skin TWO KEYS TO SCIENTIFIC MEASUREMENT: 1) having an operational definition that specifies a measurable event 2) having a device that measures that event Validity Reliability and Power: - good measures have three properties: 1) Validity  refers to the extent to which a measurement and a property are conceptually related - ex. frequency of smiling is a valid way to define happiness because people all over the world tend to smile more often when they feel happy but the number of friends a person has is not a valid way to define happiness (happiness and smiles more related than happiness and friends) 2) Reliability  the tendency for a measure to produce the same measurement whenever it is used to measure the same thing - ex. if a persons facial muscles produced precisely the same electrical activity on two different occasions then an EMG should produce precisely the same readings on those two occasions. If it produced different readings (detected differences that didn’t exist) then it would be unreliable. - good measures also have 3) power  ability of a measure to detect the concrete conditions specified in the operational definition - ex. if persons facial muscles produced different electrical activity on two different occasions and the EMG measured no difference on those two occasions even though a difference did exist then it would be powerless - validity, reliability and powerful measures consistently detect concrete conditions that are conceptually related to the property of interest when and only when those conditions actually exist. Demand Characteristics: - once you have a valid, powerful and reliable measure you can go measure something but its not that easy as people are reactive - if we try to measure how people behave, they may be trying to behave as they think we want them to or expect them to - Demand characteristics  aspects of an observational setting that cause people to behave as they think they should - Ex. when someone you love asks do these jeans make me look fat, the right answer is no (experiencing demand) - demand characteristics make it hard to measure behavior as it normally unfolds How can demand characteristics be avoided? - observing people without their knowledge - Naturalistic observation  a technique for gathering information by unobtrusively observing people in their natural environments - ex. naturalistic observations show that the biggest groups leave the smallest tips in restaurants - unfortunately naturalistic characteristics isn’t always a viable solution to the problem of demand characteristics - 1) some of the things psychologists want to know don’t occur naturally - 2) some of the things that psychologists want to observe can only be gathered from direct interaction with a person ex. survey, tests, interviews if we wanted to know how much someone worried about dying simply watching them from a bush wont do - Although there are other ways to avoid demand characteristics: - 1) people are less likely to be influenced by demand characteristics when they cannot be identified as the originators of their actions (they can respond privately/anonymously) - 2) measure behaviors that are not susceptible to demand ex. a persons behavior cant be influenced by demand characteristics if that behavior isn’t under the persons voluntary control (you may not want the psychologists to know that you are sexually aroused but you cant prevent your pupils from dilating) - 3) Behaviors are also unlikely to be influenced by demand characteristics when people don’t know that the demand and the behavior are related. ex. you may want a psychologist to believe that you are concentrating on a task but you probably don’t know that your blink rate slows when you are concentrating Why is it important for subjects to be “blind”? - one of the best ways to avoid demand characteristics is to keep the people who are being observed from knowing the true purpose of the observation - when people are blind to the purpose of the observation they cant behave the way they think they should behave b/c they don’t know how they should behave - although when psychologists try to hide the purpose of the observation, people get curious and figure out for themselves that’s why psychologists use cover stories or misleading explanations - ex. they tell you that the study is for some other reason when it actually is not - they also use pointless measures or filler items to mislead you such as asking an irrelevant question to the study Observer Bias: Why is it important for experimenters to be “blind”? - students is psych class were told to measure the speed at which a rat can run through a maze - some students were told that they were given maze-dull bred rats (rats that were slow) and some were given maze-bright bred rats even though none of this was true - the students who thought they were measuring the speed of the maze-dull rats reported that their rats took longer to learn the maze and the students who thought they were measuring the maze bright rats reported that their rats learned the maze faster - the measurements revealed precisely what the students expected them to reveal - expectations can influence observations - the students who timed the rats probably tried to be honest, vigilant fail and objectibe but their expectations influenced their observations in subtle ways that they could neither detect nor control - expectations can influence reality - students who expected their rats to learn quickly may have unknowingly done things to help that learning along ex. muttering “oh no” when the bright rat looked the wrong direction - observers expectations can have a powerful influence on both their observations and on the behavior of those whom they observe - one of the techniques psychologists use to avoid these influences is double blind observation  observation whose true purpose is hidden from both the observer and the person being observed -ex. if the students had not been told which rats were bright and which were dull then they wouldn’t have had any expectations about their rats thus their expectations couldn’t have influenced their measurements - common practice in psych is to keep the observers as blind as the participants - ex. measurements are often made by research assistants who do not know what is being studied or why and who thus don’t have any expectations about what the people being observed will or should do - worlds blindest experimenter : the computer (can present info to people and measure their responses w/o having any expectations whatsoever. Descriptions: - Two techniques used to deal with big pages full of numbers (data collected) : graphic representations and descriptive statistics Graphic Representations: What is a frequency distribution? - vision is our most sophisticated sense and human beings typically find it easier to understand things when they are represented visually than numerically or verbally - psychologists often create graphic representations of the measurements they collect - frequency distribution  graphic representation of measurements arranged by the number of times each measurement was made - gaussian distribution/normal distribution  mathematically defined frequency distribution in which most measurements are concentrated around the middle - the normal distribution is symmetrical, has a peak in the middle and trails off at both ends (bell curve) Descriptive Statistics: What are the two major kinds of descriptive statistics? - brief summary statements that capture the essential information from a frequency distribution are called descriptive statistics - the two important types of descriptive statistics are: 1) those that describe the central tendency of a frequency distribution 2) those that describe the variability in a frequency distribution - Descriptions of central tendency are statements about the value of measurements that tend to lie near the center or midpoint of the frequency distribution - The three most common descriptions of central tendency are: 1) mode  value of the most frequently observed measurement 2) mean  the average values of all the measurements 3) median  the value that is “in the middle” ex. greater than or equal to half the measurements and less than or equal to half the measurements - In a normal distribution, the mean median and mode all have the same value but when the distribution is not normal these three descriptive statistics can differ What are the two measures of variability? - range  the value of the largest measurement in a frequency distribution minus the value of the smallest measurement - when the range is small, the measurements don’t vary as much as when the range is large - standard deviation  a statistic that describes the average difference b/w the measurements in a frequency distribution and the mean of that distribution (on average, how far are the measurements from the center of the distribution?) Explanation: Discovering Why People Do What They Do: - Scientific research always begins with the measurement of its properties but its ultimate goal is typically to discover the casual relationships between properties - Ex. we know happy people tend to be healthier but what we really wanna know is if its the happieness that is the cause of them being healthy - Measurements tell us what happened but not why - Correlation to examine whether two things are related - Causation to examine whether the relationship b/w two things is casual - Drawing conclusions to determine what kind of conclusions these techniques do and do not allow us to drw Correlation: - if you went up to people and insulted them and then proceeded to ask for the time of day they probably wouldn’t give it to you - you may be convinced that being insulted causes people to refuse requests from the people who insulted them - you may conclude that being insulted by someone and refusing to do that person a favor have a casual relationship - question is how did we manage to measure how much insulting and refusing occurred but also find the relationship b/w insulting and refusing Patterns of Variation: How can we tell if two variables are correlated? - measurements can only tell us about properties of objects and events but we can learn about the relationships b/w objects and events by comparing the patterns of variation in a series of measurements - for study of insults and requests three things were done 1) a pair of variables (properties whose values can vary across individuals over time) were measured - the value of one variable can vary from not insulted to insulted and the second variable can vary from refused or agreed 2) then you did this again and again (asked more than one person)(made a series of measurements rather than just one) 3) tried to discern a pattern in your series of measurements - you notice that every time someone is insulted they refuse and every time theyre not insulted the agree - this is a particular pattern of variation - this synchrony is known as a pattern of co variation or correlation  variations in the value of one variable are synchronized with variations in the value of the other Treatment Response Insulted Refused Not insulted Agreed This table is an example of correlation/pattern of covariation - by looking for synchronized patterns of variation we can use measurement to discover the relationships b/w variables - ex. adults are taller than children --> just shorthand way of saying as age varies from young to old, the value of height varies from short to tall - correlations are the fundamental building blocks of knowledge - correlations allow us to predict the future - ex. given the correlation b/w age and height, can you predict how tall Bob will be on his next birthday --> yes, probably taller if he is turning 21 than if he is turning 2 - when two variables are correlated knowledge of the value of one variable allows us to make predictions about the value of the other variable Whats the difference b/w a positive and negative correlation: - positive correlation  relationship b/w two variables in more-more or less-less terms (ex. when we say less spinach is associated with less longevity and more spinach is associated with more longevity) - negative co
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