Professor Paul Bloom: What we've been talking about so far inthe course are human universals, what everybody shares. So, we've beentalking about language, about rationality, about perception, about theemotions, about universals of development, and we've been talking aboutwhat people share. But honestly, what a lot of us are very interestedin is why we're different and the nature of these differences and theexplanation for them. And that's what we'll turn to today.
;W J%HL'\,wZ0So first, we'll discuss how are people different, different theoriesabout what makes you different in a psychological way from the personsitting next to you, and then we'll review different theories about whypeople are different. And this is the class which is going to botherthe most people. It's not dualism. It's not evolution. It's thisbecause the scientific findings on human psychological differences are,to many of us, shocking and unbelievable. And I will just try topersuade you to take them seriously.心理学空间r,@:TM5AAu
Okay. So, how are people different? Well, there's all sorts of ways.Your sexual identity--It is at the core of your being for almost all ofus whether you're male or female. How we refer to you in language, whatpronoun we use, is indexed on how we--on your--on how--whether you'remale or female and related to that though imperfectly is your sexualorientation, who you're attracted to. The question of why some of usthink of ourselves as males and others as females, and the question ofwhy some of us would ideally want to have sex with males, others withfemales, others with both, and then a few others who have harder todefine desires, is such a good question that we're going to talk aboutit after spring break while all the sexual desire has been spent andyou could focus on [laughter] on a scientific discussion of this--notthat I recommend you do that on spring break.
z4f'i's ]xv0How happy are you? This is also such a good topic it's going to getits own class. The very last class of the semester is devoted tohappiness and the question of what makes people happy, what makespeople unhappy, and what makes people differ in their happiness. If Iasked you to rank how happy you are from a scale of 1 to 10, thenumbers would differ across this room. And there's different theoriesas to why. Your success and failure in life--This is somewhatinteresting because you could study this in more or less objectiveways. We don't have to ask people. We could look at your relationships,how they begin, how they end, your job satisfaction. We could look atyour criminal records. Some of you are going to see time. Most willnot. Some of you will get into little troubles all through your life.Some of you already have seen the inside of a police station, possiblya lineup. Others couldn't go near such a thing. What determinesthat?心理学空间U!Q[&RD
4YcL"L~4F0And at the root of all human differences are two main factors. Andso, I want to talk about the two main interesting factors. One ispersonality. The other is intelligence. And this is what--These are thedifferences I'll talk about today first from the standpoint of how dowe characterize them, how do we explain them, and then from thestandpoint of why these differences exist in the first place.
One way to characterize personality is in terms of people's stylewith dealing with--in dealing with the world and particularly theirstyle with dealing--in dealing with other people. So, you take a simplecharacter you know of and you could talk about that person'spersonality. You could talk about it in terms of being impulsive,irresponsible, sometimes lazy, good-hearted. You could compare thatperson's personality with other people's personalities such as mycolleague who gave a talk last class. He's wonderful. He's responsibleand reliable and very kind [laughter] and different from Homer. And so,this difference is a difference in personality.心理学空间$@B.@4zCI9Y
E?D0s$K[0Now, when we talk about personality we're talking about somethingelse as well. We're talking about a stable trait across situations andtime. So, if all of a sudden the person next to you kind of smacks youin the head, you might be angry but we wouldn't call that "personality"because that's something that's a result of a situation. We'd all feelthat way in that situation. It's "personality" if you walk around allthe time angry. That'd be a stable trait. That'd be something you carryaround with you and that's what we mean by personality.
Now, how do we scientifically characterize differences inpersonality? And it's a deep question. There's been a lot of attemptsto do so. Any assessment has--Any good assessment has to satisfy twoconditions. And these are terms which are going to show up all overpsychological research but it's particularly relevant for this sort ofmeasure. One is "reliability." Reliability means there is notmeasurement error. And one crude way to think about reliability is, atest is reliable if you test the same person at different times and youget the same result. My bathroom scale is reliable if whenever I standon it, it gives me more or less the same number. It's not reliable ifit's off by ten pounds in the course of a day. Similarly, if I give youa personality test now and it says that you're anxious and defensive,well--and then give it to you tomorrow and it says you're calm and openminded, it's not a reliable test. So, reliable is something you couldtrust over time.
"Validity" is something different. Validity is that your testmeasures what it's supposed to measure. So, validity means it's sort ofa good test. Forget about how reliable it is. Does it tap what you'reinterested in? So, for example, suppose I determine your intelligenceby the date of your birth. I figure out what day you were born and Ihave a theory that, from that, predicts how smart you are. That's myintelligence test, the date of your birth. Maybe people born in Januaryare the dumbest, people born in December are the smartest. Is that--Iwas born on Christmas Eve. [laughter] Is that a reliable test? Yes,it's a wonderfully reliable test. I'll test you today; I'll test youtomorrow; I'll test you next year; I'll test you the day you die; I'llget the same IQ score. Is it a valid test? It's a joke. It's absolutelynot a valid test. It has nothing to do with intelligence. But younoticed these are two different things. Something can be reliable butnot valid and something can be valid and not reliable.
Now, there are no shortage of personality tests. You could get themall over the place including on the web. So, I took one recently. Itook "which super hero are you?" [laughter] And it's a series ofquestions determining what super hero you are. You could take thisyourself if you want to. The same web page, by the way, offers you atest in whether you're "hot" or not. We'll discuss that later. And whenI did this [laughter] it told me I was Batman [laughter] and "you aredark, love gadgets, and have vowed to help the innocent not suffer thepain you have endured." Now, the honest-- [laughter] Now, to be honestthough, it's neither reliable nor valid. When I first did the test Icame up as "The Incredible Hulk." I then changed my answers a bit andwas "Wonder Woman." [laughter] And finally, out of frustration, Icarefully tailored my answers so I would be Batman. But the fact that Ican do that, well, raises questions about both the reliability of thismeasure and its validity.
g@H0]6z Y0Here is an example – a real world example. This is, in black andwhite form, a version of the Rorschach test, the Rorschach inkblottest. How many people have heard of the Rorschach test? Okay. Is thereanybody here who has actually, in any sort of situation, taken aRorschach test? Some people scattered in the room have taken them. Itwas originally used only for psychiatric cases but then becameextremely common. About eighty percent of clinical psychologists claimto use it and most graduate programs in the American PsychologicalAssociation who are accredited teach it. Catholic seminaries use it forpeople who want to join the seminary.
B/c fPPR*xN,h#w0It was invented by a guy named Herman Rorschach. He devoted hisentire life to the inkblot test. His nickname when he was a teenager –I am not kidding you – was "Inkblot." [laughter] And the idea is bylooking at these inkblots and then seeing what somebody says you getgreat insights into the nature of their personality, into what theyare. Anybody want to try it? Come on. Yes. What do you see?心理学空间8n1Y8Y)NN#KW;G
%_F*ANH(Ls$y0Student: I see two people holding hands pressed together.
L:~&N/~$IW0Professor Paul Bloom: Two people holding hands pressedtogether. Very good. Anybody have a different reading? Yes, in back.Yes. Yes.
M8J1h7[vV0E WkD:|0Student: Dancing bears.
\S7b6U?:P] XJ0Professor Paul Bloom: Dancing bears. Okay. Good.[laughter]Good. Okay. I got to write your name down-- [laughs][laughter] reportyou to health-- No. Dancing bears, very good. Anybody else? One other.Yes.心理学空间\'or]? D/wA
.Od@ fY"NU0Student: A man in a ski mask.心理学空间5Zo%[6uI8V CR#O|z+v
Professor Paul Bloom: A man in a ski mask. Well, it turns outthat there are right answers and wrong answers to the Rorschach test.According to the test, and this is from a real Rorschach test, "it isimportant to see the blot as two human figures, usually females orclowns." Good work over there. "If you don't, it's seen as a sign youhave problems relating to people." [laughter] If you want to go for "acave entrance" or "butterfly" or "vagina," that's also okay.[laughter]
TaY4s g%NX0Now, the Rorschach test is transcendently useless. It has beenstudied and explored and it is as useless as throwing dice. It is asuseless as tea leaves. Nonetheless, people love it and it's used allover the place. It is used for example in child custody cases. If youhave broken up with your partner and you guys are quarreling over whogets to keep the kids, you might find yourself in a shrink's officelooking at this. And in fact, this is why they end up on the web. Thereare services. There are people who have been kind enough to put on theweb these inkblots, including the right answers to them. But they areworthless as psychological measures.心理学空间W.t$Q7q c
Can we do better? Well, we probably can. Gordon Allport did a studywhere he went through the dictionary and took all of the traits that hebelieved to be related to personality and he got eighteen thousand ofthem. But what was interesting was they weren't necessarily independenttraits. So, the traits like "friendly, sociable, welcoming,warm-hearted" seemed to all tap the same thing. So, Cattell and manyothers tried to narrow it down, tried to ask the question, "In how manyways are people's personalities different from one another?" How manyparameters of difference do you need? How many numbers can I give youthat would narrow you in and say what personality you are?
-Ag-PAb]CU0One approach was from Eysenck, who claimed there were just two. Youcould be somewhere on the scale of introverted-extroverted, andsomewhere on the scale of neurotic and stable. And since there'sbasically two types of traits with two settings for each, there arebasically four types of people. Later on he added another trait whichhe described as "psychoticism versus non-psychoticism" that crudelymeant whether you're aggressive or empathetic. And then you have threetraits with two settings each giving you eight types of people. Lateron Cattell dropped it down into sixteen factors. So, these sixteenpersonality factors are sixteen ways people would differ. And so, if Iasked you to describe your roommate along these sixteen dimensions, youshould be able to do so.
8F3TJZc|2q^vX s#bH0More recently, people have come to the conclusion that two or threeis too few, but sixteen might be too many. And there's a psychologicalconsensus on what's been known as "The Big Five." And "The Big Five"personality factors are these, and what this means is when we talkabout each other and use adjectives, the claim is we could do so inthousands of different ways, but deep down we're talking about one ofthese five dimensions. This means that when a psychological testmeasures something about somebody, about their personality, if it's agood test it's measuring one of these five things. And it means that,as people interacting with one another in the world, these are the fivethings that we're interested in. So, one of them is "neurotic versusstable." Is somebody sort of nutty and worrying or are they calm?"Extrovert versus introvert." "Open to experience versus closed toexperience." "Agreeable," which is courteous, friendly versus nonagreeable, rude, selfish. And "conscientious versus not conscientious,"careful versus careless, reliable versus undependable. A good way tothink about these things is in terms of the word "ocean," o-c-e-a-n.The first letter captures openness, conscientiousness, extroversion,agreeableness, and neuroticism. And the claim is those are thefour--the five fundamental ways in which people differ from oneanother.
4j8sQ(PQ;]p0Well, why should we believe this? Why should we take this theoryseriously? Well, there's actually some evidence for it. It seems tohave some reliability in that it's stable over time. So, if you testpeople over years--If I test your personality now on the five traitsand test you five years from now, it will not have changed much. Andonce you pass the age of thirty, it's very stable indeed. If you thinkabout your parents and then give Mom and Dad a mental test on wherethey stand on each of the five traits, ten years from now Mom and Dadwill still be there. It also seems to get agreement across multipleobservers. So, if I ask for each of their five traits--If I ask yourroommate what he or she thinks of you, then I ask your professor whathe or she thinks of you and your mom what he or--what she thinks ofyou, [laughter] how would--back to gender--How would they match up?They tend to overlap a lot. You walk around and you leave--and yourpersonality leaves a trail in the minds of people around you. And thistrail is characterized in terms of these five dimensions.心理学空间;s_R7Rs@y
]7Aq v"J)Yk0Finally, it seems to be--predict real-world behavior. If this didn'thave anything to do with the real world, you wouldn't be very happycalling it valid, you wouldn't take it seriously as a test, but itdoes. So, conscientiousness--how you score on a conscientious scale,relates to how faithful you are to your spouse. How openness--open youare on a psychological personality test relates to how likely you areto change your job. "Extroverts" look people in the eye more and havemore sexual partners because they're extroverts. So, these are realscales. The "Batman, Hulk, Wonder Woman" doesn't correspond to anythingin the real world, but where you stand on each of these five dimensionsdoes seem to capture it.
y;r@&{4S#[ Xr0As an example of the agreement, by the way, somebody did a study ofseveral of the characters on the television show "The Simpsons" becausethey wanted to find characters which everybody knew. And they hadthirteen subjects judge these Simpson characters on each of the fivedimensions. These is "openness, neuroticism, conscientiousness, andextroversion" and they found considerable agreement. And this isn'tactually--What I've covered up [on the slide] is the "agreeableness."So, for those of you who have never seen the television show, this isall going to be confusing, but those of you who have, can you guesswhich characters would be particularly agreeable? Anybody guess.Yeah.