Complete collection of objects or events that might be measured Sample: Partial collection of objects or events that is measured Deck of cards is the population, cards in your hand the sample Law of large numbers: a statistical law stating that as sample size increases, the attributes of a sample will more closely reflect the attributes of the population from which it was drawn As sample of cards increases, ratio of black to red becomes more accurate Coincidences: people underestimate the chances of them, you can bet hat in any group of 24 or more people that at least 2 of them share the same birthday Frequency distributions: a graphical representation of the measurements of a sample that are arranged by the number of times each measurement was observed Normal distribution (bell curve): a frequency distribution in which most measurements are concentrated around the mean and fall off toward the tails, and the two sides of the distribution are symmetrical Men vs.. Women comparing fine motor skills, on average, women score better than men Descriptive statistics: brief summary statements that capture the essential info from a frequency distribution
Descriptions of central tendency: summary statements about the value of the measurements that lie near the center or midpoint of the distribution Mode: The most frequent measurement Mean: The average of the measurements Median: The middle measurement, half are greater and half are less In normal distributions, these are all equal Descriptions of variability: Statements about the extent to which the measurements in a frequency distribution differ from each other Range: Numerical difference between the smallest and largest measurements Also measures known as variance and standard deviation, but they are complicated Demand characteristics: those aspects of an observational setting that cause people to behave as they think an observer wants or expects them to behave Hinder our attempts to measure behavior as it normally unfolds Naturalistic observation: a method of gathering scientific knowledge by unobtrusively observing people in their natural environments Biggest groups tend to leave the smallest tips in restaurants, hungry shoppers buy the most impulse items at grocery store, golfers cheat the most when they play several opponents at once Problems: 1 . Some of the things we want to observe don’t occur naturally 2.
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Some things we want to observe can only be gathered from direct interaction with a person Allow people to respond privately or anonymously a way to avoid this problem Trick subjects into believing the demand and the behavior aren’t related Keep the participants blind to the observer’s expectations, don’t know what is Use filler items to mask the true purpose of the observation Blind observers: humans tend to see what they expect to see Students asked to measure the speed with which a rat learned to run through a maze, some told their rat had been bred to be “maze dull” and others to be “maze right” Rats actually the same breed, but students marked them according to their thoughts Expectations can influence observations: easy to make errors when the observers have predisposed attitudes Expectations can influence reality: observers unknowingly do things to help their subjects according to their predisposed thoughts Help rats learn quicker, mutter “Oh no” when turn a wrong corner Double-blind: an observation whose true purpose is hidden from the researcher as well as from the participant Conduct same experiment but don’t tell students which rats were smart ND which were dull Discovery of the causal relationships between properties is the ultimate goal of scientific research Stand on street corner and insult or not insult others then ask for the time, direct correlation between response and treatment (cause) By comparing patterns of variation in a series of measurements, we can learn about the relationships between objects and events First you measure a pair of variables: a property whose value can vary or change Insult or not insult, refuse or agree Second you make a series of measurements by conducting study multiple times Then you try to discern a pattern of variation
Correlation: a pattern of co-variation, when variations in the value of one variable are synchronized with variations in the value of the other Positive correlations described as “more-more” (more spinach leads to more longevity) or “less-less” (less spinach leads to less longevity) Negative correlation described as “more-less” (more bacon leads to less longevity) or “less-more” (vice versa) Correlation coefficient: a statistical measure of the direction and strength of a correlation, which is signified by the letter r Always has a range (0-24 if measuring hours of sunshine per day), but most moon to have -1 to 1 Perfect positive correlation: when r = 1 Perfect negative correlation: when r = Uncorrelated: when r = O, no systematic relationship between variables Negative imperfect correlation: when r is between -1 and O Correlation coefficient is a measure of both the direction and strength of the relationship between two variables Minuends: our brains are so eager to connect causes with effects that they often make connections that aren’t really there (playing arcade games when there is no money in the machine) Conversely, our minds fail to detect causal relationships that do exist (washing hands and scalpels before surgery, dads to infection) Natural correlations: a correlation observed between naturally occurring variables They can tell us whether two variables are related, but not what kind of relationship Two people chatting in public All variables that are causally related are correlated, but not all variables that are correlated are causally related Height and weight, neither causes the other but they are related Third variable correlation: the fact that two variables may be correlated only because they are both caused by a third variable X 0 Y: TV violence (X) causes aggressiveness (Y)
Z 0 X and Y: lack of adult supervision (Z) causes TV violence and aggressiveness Possibility of a third variable can never be dismissed Matched samples: an observational technique whereby the participants in two samples are identical in terms off third variable Observe only children who are supervised exactly 87% of the time Matched pairs: an observational technique whereby each participant in one sample is identical to one other participant in another sample in terms of a third variable Observe children who experience different amounts of adult supervision, but make sure that for every child we observe ho watches a lot of television and is supervised 24% of the time, we also observe a child who doesn’t watch television and is supervised 24% of the time, ensuring that both groups have the same amount of supervision on average Neither technique can dismiss the possibility of a third variable correlation though, because they might dismiss a particular third variable but don’t eliminate all potential third variables Third-variable problem: the fact that the causal relationship between two variables can’t be inferred from the correlation between them because of the ever-present usability of third-variable correlation If we care about causality, then natural correlations can never tell us what we really want to know Experiment: a technique for establishing the causal relationship between variables Manipulation: a characteristic of experimentation in which the researcher artificially creates a pattern of variation in an independent variable in order to determine its causal powers, usually results in the creation of an experimental group and a control group Wireless phones interfering with TV reception, test it out by standing in front of the TV with the hone If we manipulate the amount of violent TV a kid watches, we never have to ask if a third variable caused aggressiveness 3 Steps of an experiment Perform a manipulation. Independent variable: variable that is manipulated (amount of TV watched). Experimental group: the group of people who are treated in a particular way. Control group: the group of people who are not treated in this particular way Measure the pattern of variation.
Dependent variable: the variable that is measured (aggressiveness) Check to see whether the patterns of variation in the dependent and independent variables are synchronized Self-selection: the case n which a participant’s inclusion in the experimental or control group is determined by the participant Randomization: procedure that uses random events to ensure that a participant’s assignment to the experimental or control group isn’t determined by any third variable Both groups have roughly equal number of all types of people Paul Brock discovered that people who lose their ability to speak often have damage in a particular spot on the left sides of their brains (Brooch’s area) Transcriptional magnetic stimulation (TM’S): mimics brain damage, can direct TM’S pulses to particular brain egging (turning them of and then measure temporary changes in the way a person moves, sees, acts etc Statistically significant: When the odds that random assignment failed are less than 5% Inferential statistics: tells scientists what kinds of conclusions or inferences they can draw from observed differences between the experimental and control groups Internal validity: the characteristic of an experiment that allows one to draw accurate inferences about the causal relationship between an independent and dependent variable Independent variable effectively manipulated Dependent variable has been measured in unbiased way with valid, powerful and reliable measure Correlation has been observed between the pattern of variation created in the independent variable and dependent variable External validity: a characteristic of an experiment in which the independent and dependent variables are operationally defined in a normal, typical, or realistic way Theory: a hypothetical account of how and why a phenomenon occurs Heat is a result of rapid movement of particles Hypothesis: a testable prediction derived from a theory If objects are slowed, then object should become cooler
Experiments test hypotheses Random sampling: technique for choosing participants that ensures that every member of a population has an equal chance of being included in the sample Rarely done by psychologists though Sometimes generality doesn’t matter: if 1 person does it, it is important Sometimes generality can be determined: use numerous non-random samples to become confident that results would generalize to the population at large Sometimes generality can be assumed: few willing to take experimental drug that could make us smarter or lead to slow painful death Informed consent: written agreement to articulate in a study Freedom from coercion Protect from harm Risk-benefit analysis Debriefing: a verbal description of the true nature and purpose of the study Chapter 5 – Memory Greg had a tumor that damaged his temporal lobe that’s crucial for forming and retaining memories Demeanor changed when his dad died, he became sad even though he couldn’t remember his death Memory: ability to store and retrieve information over time Encoding: the process by which we transform what we perceive, think or feel into an enduring memory Memories are made by combining info we already have in our rains and new info that comes in through our senses Memories are constructed not recorded Elaborative encoding: the process of actively relating new info to knowledge that is already in memory Semantic Judgments required participants to think about the meaning of words Bubbles P. A gambler that thought about numbers meanings Thinking about meaning helps encode memories without thinking Rhyme Judgments required participants to think about the sound of words Semantic Judgments almost always yield better memory than rhyme Judgments Visual Judgments required participants to thin about the appearance of words Associated with left temporal obey and lower left part of frontal lobe Visual imagery encoding: the process of storing new info by converting it into mental pictures Visualizing can substantially improve memory, subjects who visualized words remembered twice as many as those who repeated them Relate incoming info to knowledge already in memory Two different mental placeholders – visual and verbal Organizational encoding: the act of categorizing info by noticing the relationships among a series of items Uses tricks such as grouping or categorizing Waitresses with food orders Points out similarities between items, and relationships help us memorize Upper reface of left frontal lobe Memory Storage: The process of maintaining info in memory over time Sensory memory store: The place in which sensory info is kept for a few seconds or less Remember rows of letters, only could recall half High tone cued to report on top row, medium tone for middle and low tone for bottom, people almost always recalled the entire row Iconic memory: fast-decaying store of visual information (1 sec or less) Echoic memory: fast-decaying store of auditory information (5 sec or less) Short term memory store: A place where nonsense info is kept for more than a few seconds but less than a minute (15-20 seconds) Limited in how long and how much can we can remember 7 meaningful items Chucking: combining small pieces of info into larger clusters or chunks that are more easily held in short-term memory Rehearsal: the process of keeping information in short-term memory by mentally repeating it Remembering a telephone number Working memory: active maintenance of info in short-term storage Includes operations and processes we use to work with info in short-term memory Long-term memory store: a place in which info can be kept for hours, days, weeks or years No known capacity limits
Can recall memories even if they haven’t thought of them in years Recognize 90% of classmates faces 50 years after graduation DIAGRAM ON 177 Hippocratic region of brain is critical for putting new info into the long-term store Acts as an index, no longer needed once memory is integrated Interrogated amnesia: the inability to transfer new info from short term into long term Retrograde amnesia: inability to retrieve info that was acquired before a particular date, usually the date of an injury or operation Act of sending a neurotransmitter strengthens the connection between two neurons, making it easier for them to transmit to each other he next time Plays – sea slug, shocks the tail and remembers quickly the next time but not in an hour, doing it more and more develops an enduring memory Synapses used for short-term storage (enhanced release) and long-term storage (growth of new synapses) Long-term potential (LET): Enhanced neural processing that results from the strengthening of synaptic connections Occurs in several pathways in hippopotamus, induced rapidly, lasts for a long time AMANDA Receptor: a Hippocratic receptor site that influences the flow of info from one neuron to another across the yeans by controlling the initiation of L TAP Retrieval: The process of bringing to mind info that has been previously encoded and stored Retrieval cue: external info that is associated with stored info and helps bring it to mind Info is sometimes available in memory even when it is momentarily inaccessible and that retrieval cues help us bring that inaccessible info to mind Giving hints like furniture’ or fruit’ after memorizing words Encoding specificity principle: idea that a retrieval cue can serve initially encoded Thoughts and feelings we had at the time the event occurred
Drunk studying means being doing better on exam when drunk than sober State- dependent retrieval: tendency for info to be better recalled when the person is in the same state during encoding and retrieval Learning words under water or above water, better recalled where learned Transfer appropriate processing: memory is likely to transfer from one situation to another when we process info in a way that is appropriate to the retrieval cues that will be available later Successful retrieval comes from hippopotamus, trying to retrieve comes from right frontal lobe Explicit Emory: the act of consciously or intentionally retrieving past experiences Recalling last summer vacation Implicit memory: the influence of past experiences on later behavior and performance, even though people aren’t trying to recollect them and aren’t aware that they are remembering them Greg persistent sadness after his father’s death yet no conscious memory Procedural memory: the gradual acquisition of skills as a result of practice, or knowing how to do things Riding a bike, shifting gears in a car Priming: an enhanced ability to think of a stimulus, such as a word or object, as a exult of a recent exposure to the stimulus Told the word moon, named Tide as favorite detergent Amnesia patients show priming effects (implicit memory), write down a word that comes to mind after tab _ Semantic memory: a network of associated facts and concepts that make up our general knowledge of the world Use of hippopotamus not required Episodic memory: the collection of past personal experiences that occurred at a particular time and place Mental time travel Seven sins: transience, absentmindedness, blocking, memory misinformation, suggestibility, bias, and persistence Transience: forgetting what occurs with the usage of time Occurs during storage phase Rapid drop-off in retention during first 20 miss, then slow after that Quality of memories also changes (Clinton) Retroactive interference: Situations in which later learning impairs memory for info acquired earlier Do same thing in work everyday, on Friday you forget what you did on Monday Proactive interference: earlier learning impairs memory for info acquired later Use same parking lot everyday, confuse your spot with earlier ones Absentmindedness: lapse in attention that results in memory failure Get out of cab and forget to grab your luggage in the trunk
Results from divided attention, low levels of left frontal activity Prospective memory: remembering to do things in the future Remember times and places that your classes meet Blocking: failure to retrieve info that’s available in memory even though you are trying to produce it Full-blown retrieval failure Tip-of-the-tongue experience: the temporary inability to retrieve info that is stored in memory, accompanied by the feeling that you are on the verge of recovering the info Common with names of people and places Eyewitness misidentification – watching TV before getting raped, associate rape with he face on TV Misidentification can land people in Jail Source memory: recall of when, where and how info was acquired Forget when or where they saw the face, but remember seeing it False recognition: a feeling of familiarity about something that hasn’t yet been encountered before Lists of words associated with sweets and sewing Auditory cortex and visual cortex Suggestibility: the tendency to incorporate misleading info from external sources into personal recollections No television film of the moment when the plane crashed yet people say they saw it and tell the speed and angle that it hit Being lost as a child
First memories between 3 to 5 years of age Psychotherapy patients for depression emerged with recovered memories of forgotten childhood sexual abuse, but not necessarily accurate Bias: the distorting influences of present knowledge, beliefs, and feelings on recollection of previous experiences Consistency bias: people reconstruct the past to fit what they presently know or believe Coupes whose relationships sour over time recalled initial evaluations were more negative Change bias: exaggerate difference between what we feel or believe now and what we felt or believed in the past Report that love has increased over time, subjective memory Self-enhancing or egocentric bias: exaggerate the change between present and past in order to make ourselves look good in retrospect Persistence: the intrusive recollection of events that we wish we could forget Occurs after traumatic incidents, such as house burning down Flashbulb memories: detailed recollections of when and where we heard about shocking events Such as 9/1 1, not always entirely accurate Magical Are sins virtues or vices? Can be either depending on situation Childhood amnesia: lack of memory for our early years Usually around 3 years