I reprise an earlier post that seems appropriate. Follow the link to some guidelines for success as a student (and in life).
I reprise an earlier post that seems appropriate. Follow the link to some guidelines for success as a student (and in life).
I’m a science geek. I love films about science, and am especially fond of old films related to psychology and neuroscience. Today I was reminded of a segment from Zimbardo’s 1990 Discovering Psychology series in which Dick Thompson explains his research. Thompson very nicely explains his discovery of a region of the cerebellum where the memory responsible for eyeblink conditioning resides. In rewatching it, I noticed something — the computer trace illustrating the lack of a conditioned eyeblink after the interpositus nucleus had been lesioned looked oddly familiar. Sure enough, it was the same trace that had been used 40 seconds earlier to represent the absence of a conditioned blink before learning had occurred. Sadly, and for reasons that we can only imagine, the produce of the film chose to reuse the pre-learning trace rather than showing the actual post-lesion trace that Thompson was describing. My conclusion that this was a decision of the producer and not a deception of the part of Thompson is based on two factors: 1) while we hear Thompson’s voice describing the post-lesion trace, we do not see his finger pointing at the features that he describes (something that he had done as he presented the pre-learning and CR traces); and 2) Dick was a friend whom I knew to be totally honest and above-board with regard to his science.
Lesions of the interpositus do, as Thompson described, eliminate the memory of the learning, and prevent future eyeblink conditioning. It is unfortunate that the reuse of the pre-lesion image might raise doubts about this conclusion in the minds of scientifically curious (and especially observant) people who do not know this literature. Science is based on the honest and free exchange of information; film-making is based on entertainment, and honesty sometimes takes a back seat.
I will continue to show this segment to my classes, but will each time be saddened by the thought that, with regard to the post-lesion trace, Thompson was describing an image that we do not see.
Thoughts as a result of the recent SfN Meeting (relevant Abstract Number is in parentheses):
Monarch butterflies use at least three cues for navigation: the sun (coupled with an internal clock), polarization pattern in the sky, and the earth’s magnetic field. This is determined by tethering the butterflies in a flight simulator, manipulating these cues, and watching them fly. (269)
Maybe we should think about habituation in a totally different way. Thanks, Cathie Rankin, for suggesting this. See her abstract for details. (630.10)
Pavlovian-to-Instrumental Transfer… I need to think more about this when I teach Learning, and when I plan my earthworm studies. Vinn Campese triggered these thoughts. (694.10)
Earthworms have sex. To what extent is this behavior dependent on hormones? (Not sure why I started thinking about this. Maybe it was the always-entertaining Neuroendocrine Social.)
Rats solve the Travelling Salesman Problem. (535.22)
Rats can show emotional contagion (one rat acts afraid, and rats that observe the scared rat do, too), but the observers are not learning to be afraid. (Ewelina Knapska 465.03 and the talk that preceded hers)
It’s great to see worthy people receive recognition. My friends Julio Ramirez and Debra Bangasser received awards from Women in Neuroscience—Julio (Davidson College) for his extensive and successful mentoring of women (in fact, he is an equal opportunity mentor) and Debra (Temple U) for her already-proven potential as an excellent scientist.
Albion students and alums rock!
A colleague asked me recently how I explain “degrees of freedom*.” This got me thinking; here’s a story that might help to clarify the concept.
Imagine that you must determine the average number of children to be picked up at each stop along a school bus route. There are 20 stops along the route. This particular bus serves areas of private residences and apartment complexes, so you are pretty sure that there will be variability in the numbers.
In a perfect world where all data are readily available, you would simply count the kids at each stop. This would yield an answer without error. You set out to do this, but at the end of the route you realize that you have only 19 data points—hard to believe, but you must have dozed off at some point and missed a stop. You now have all but one of the data points necessary for an errorless answer; if you use these 19 points to estimate the average, how far off could you be?
The missing point (in fact, each data point) contributes 1/20 of the information that factors into the final True Answer. The missing data point accounts for 5% of the total information, but you have 95% of the information—surely your answer must be close to correct.
The answer is that you don’t really know. The missing data point could have had any value. However, reason and common sense suggest that it is not very likely that the missing number would be lower than the smallest number that you recorded, or larger than the largest number. It might be, of course, but if you were to randomly exclude one of the 20 points (which is essentially what you have done) there is only a 1 in 10 chance that you would exclude either the lowest or highest number—you can be 90% sure that the missing point is not an extreme. If you use the average of the 19 points as your estimate of the True Answer, and if you excluded the lowest number, then your estimate will be too high by (the difference between your estimate and this lowest number)/20, and if you excluded the highest number than your estimate will be too low by (the difference between your estimate and this highest number)/20. The divisor of 20 is there because each of the 20 points contributed 1/20 of the estimate. You are therefore 90% sure that the True Answer lies in the range
[Your Estimate – (Your Estimate – Lowest Number)/20] < True Answer < [Your Estimate + (Your Estimate – Highest Number)/20]
Algebraically this reduces to a 90% chance that the maximum error is YE/10 – (LN + HN)/20**.
This represents the amount that the true answer is free to vary from your estimate when 19 of the 20 values were free to vary. Once you decided to accept the mean of these 19 as the average for the entire group of 20, the data point that you missed could no longer vary – its value was fixed at the mean of the others. This estimate, then reflects a situation with 19 points free to vary: 19 degrees of freedom.
Now repeat this thought experiment, except that this time you collected your data after an especially rough night of little sleep. At the end of the route you realize that you have only 1 of the 20 data points (it was a really hard night!). If you decide to use this single data point as an estimate of the true average for all the stops, how far off will you be? The missing values represent 95% of the information that you need—you have only 5% of the information. Surely your answer must be way off. In this case only one value was free to vary—19 were determined when you decided to use the one recorded measure as the mean for all of them. Here you had only 1 degree of freedom.
Finally, consider an intermediate situation – you miss 10 of the 20 stops. You have 50% of the information, and lack 50%, The average of your 10 data points will be far more likely to be close to the True Answer than would the “average” of the 1 data point following the rough night, but not as accurate as the estimate when you have 19 of the 20 data points. Here there are 10 points that are free to take on any value: 10 degrees of freedom.
Each missing data point allows the estimate to vary from the True Answer. The more missing points, the more the estimate will vary. Each missing point represents a lost degree of freedom: therefore the more missing data points, the fewer degrees of freedom. If there is only one missing or unknown value, there are many degrees of freedom. As the number of missing values increases, the number of degrees of freedom will decrease. With more degrees of freedom, your certainty about the accuracy of your answer increases; another way of saying this is that with more degrees of freedom, the range within which the True Answer could fall decreases.
In more general terms, the extent to which you estimate some of the statistics that enter into your ultimate answer, the fewer degrees of freedom that you have, and the more likely it is that your ultimate answer will deviate from the True Answer.
I appreciate comments. Please email me at firstname.lastname@example.org, especially if you want to point out errors in my logic or my algebra. They likely exist.
* If you don’t know the term just imagine a concept essential to your job but difficult to explain to newbies and poorly understood by most everyone, even you.
** (YE – LN)/20 + (YE – HN)/20 = YE/20 – LN/20 + YE/20 – HN/20 = YE/10 – (LN + HN)/20
Just back from the 2015 meeting of the Pavlovian Society – a scientific society founded 60 years ago and going stronger than ever. Here are some “random” thoughts:
~ Science is cool! Scientific studies of learning theory are among the coolest.
~ There were not enough studies of pure learning at the meeting.
~ The opportunity to interact with old friends is always welcome, and I have many friends in the Society.
~ Meeting new friends is also welcome, and I had the opportunity to do that as well.
~ Dick Thompson had a profound influence on the field. I’m glad to have considered him a friend.
~ Nick Mackintosh’s book is viewed by all of us older members of the Society with the same reverence. Younger students of learning should get a copy.
~ Judging by the vitality of the younger attendees and the quality of their research, the future of learning is secure.
~ Few if any members of the Society view Donald Trump as anything more than a fear-inducing stimulus.
~ Alcohol facilitates scientific discussion.
~ Mt. St. Helens is remarkably close to Portland.
~ I am glad that a few others in attendance work with small crawly things, even if those things aren’t earthworms.
~ I want to come up with the earthworm equivalent of Kim’s robo-raptor.
~ I could easily spend a week and hundreds of dollars in Powell’s.
~ Next year’s meeting can’t come soon enough.
[Reposting this, with slight modifications, from a year ago. I offer useful information for students who want to succeed.]
To all of our returning students, Welcome back!
And to the new faces on campus, Welcome!
It’s time to get serious about learning. Here are links to a few blog posts that I have written over the past few years in which I offer some guidance to students about how to succeed. I tend to think beyond immediate success in a course; these posts address issues related to doing what you need to do now so that you can get on with your life after college.
And to students who haven’t yet figured this out: professors are here to help you learn. Ask us questions, come to our office hours, view us as your allies in the quest for knowledge. If you want to understand something, we will work hard to make that happen. If you want a good grade we can’t do much for you.
A desire to understand will lead to good grades; a desire for good grades will not lead to understanding.
Four principles that will serve you well (from another prior post):
Looking forward to a great semester as we grow together.
(Now – begin to confront your ignorance: if you do not recognize the people I have quoted, get to work. Knowledge is only a Google away.)
Some of you know that I had thought I would write something deep or reflective to mark my 60th birthday. Well, yesterday came and went, and it was good: time spent with family, with data, with photos, and with live music. But I made it to 60; the brother of a friend had his life cut short yesterday at 17. There was no reason for him to die so young, just as there was no reason for me to make it this far. Life is full of small decisions and random occurrences, some of which have no impact and some of which lead to dramatic, unintended, and totally unexpected consequences. The universe truly does not care about us; it was here before us and will be here long after we are gone. But the thing is, as conscious, sapient products of the universe, we have the opportunity, for a fleeting instant of time, to experience it. Revel in that. Absorb all that life throws at you. The vast (no, make that VAST*) majority of all matter that exists has experienced nothing, and never will. You can. Marvel at that fact for a moment, then marvel at the fact that you are capable of marveling, then get back to the joyous task of experiencing all that your sense organs take in, all that your nervous system can process. Some of it is good; some of it is bad. But all of it IS, and through a combination of luck, fortuitous decisions, and a long history of success by our evolutionary predecessors, you and I can recognize that ISness. Appreciate that. I am confident that 17-year-old Troy did so for his all-too-short life, and I will continue to do so for whatever time I have left.
* used in the Dawkinsian sense.
Dear RDA Students:
I write as I contemplate the grades that I should record for each of you for your work this semester. As this is an open letter and people not familiar with me or with the class might read it, I should clarify some things. First, Research Design and Analysis 1 is the first course that psychology majors take on the road to becoming true psychologists. Students learn the one distinguishing skill that characterizes all psychologists: the ability to measure, quantify, and analyze behavior. Second, although I have been doing these things professionally for nearly 40 years, this is the first time I have taught this course. [And to those few students who rose to the challenge of the course, attended class, and put effort into your work, read this knowing that I appreciate your efforts. This does not refer to you.]
At the outset of the semester you each received a syllabus that described the material to be covered and the work that you would be expected to complete. It also indicated the consequence of turning material in late: homework more than two days late would not be accepted; papers would lose 10% per day for each day past the due date. The grading scale was presented clearly: the value of each assignment was stated, with their total summing to the 1600 points possible. Earn 60% of these points and you pass the course, 70% for a grade of C, 80% for B, 90% for an A.
In order to proceed to RDA 2 a grade of at least C (2.0) must be earned in this course. A grade of 2.0 indicates an understanding of the course material that might allow you to succeed in RDA 2; a grade below 2.0 has in the past characterized the student who will struggle in RDA 2, hence the department-mandated restriction on who proceeds to RDA 2.
I had very hard decisions to make. If I assigned course grades according to the scale published in the syllabus, all of you would pass the course, but more than 70% of you would not move on to RDA 2. I do not for a moment believe that the large number of grades < 2.0 reflects a lack of ability–no, what I saw was a lack of motivation, ownership, and caring:
So what am I to do? Rather than assign the grades earned, I decided to give you the benefit of the doubt: perhaps some of you would be capable of doing well with a professor who does a better job than do I of coaxing the work out of you. However, I cannot in good conscience pass you along to RDA 2 if you are not capable of doing the work. So, I decided to assign as your course grade the higher of
This assumes (I think reasonably) that the ability to demonstrate an understanding of the material in exams and papers is important: if you can do that you can succeed in RDA 2. Note that this exam/paper average resulted in NO penalties for those drafts of Paper 2 that were never turned in, as I did not include the grades on drafts in these calculations. However, some of the lowest course grades were earned by people who failed to turn in the draft on time; perhaps the final paper would have been better if it incorporated my feedback on the draft…
Life requires participation; success requires ownership. Own your work; care about your work; treat your work as if it matters. If you can’t be bothered to put effort into an assignment in a class, why should anyone expect that you will put effort into an assignment given to you by an employer, or by a mentor in graduate school? Why should a client expect that you will put effort into helping her get better? Why should a collaborator expect you to do your share on a project? Demonstrate that you are willing to put effort into a project and those around you will give you the benefit of the doubt. You need their trust and support, as the world generally does not care about you.
Your caring and disappointed professor
Recent events at Marshall High School prompt this post. A parent complained to the school administration about a bulletin board urging acceptance of transgenders and the display was removed. [EDIT 4/1/2015: It appears that the removal of the display happened before the parents met with school officials, and might have occurred simply because it was time for another group to mount a display.] Some students feel that their attempt to increase visibility and acceptance of others was stifled, while others are apparently praising the removal of the display. The school rock was painted with a message of acceptance, painted over surreptitiously in the night, and then repainted with another message of acceptance.
I simply want to add a few words about the science of gender—what we know about the origin of gender identity and the extent to which gender or sexual orientation a choice.
Short answer: no choice involved. Gender appears to be as much a part of one’s biological make-up as is handedness. Mammals are born with
penis or clitoris,
scrotum or labia,
vas deferens or uterus,
XY chromosomes or XX chromosomes,
large sexually dimorphic nucleus or small sexually dimorphic nucleus,
few hypothalamic estrogen receptors or many hypothalamic estrogen receptors.
You probably think that everyone possesses all of the first or all of the second items in these pairs. Wrong! Most who think of themselves as male have all of the first elements, and most who consider themselves female have all of the second, but many people are a combination of some from Column A and some from Column B. We have no control over the combination that we are dealt. Instead we are to a great extent controlled by it.
In particular, in the absence of hormonal exposure during fetal development, the brain will become female. Regardless of what the genitals look like, the individual will likely think of herself as female. If testosterone is present in the brain as it develops, the brain will become male, and the individual will think of himself as male, again regardless of the appearance of the genitals. It is the sex of the brain that plays the greatest part in determining gender identity, and this is something that the individual did not choose and cannot change.
There are people who have XY (male) chromosomes who are in every other way female, and people with XX chromosomes who are male. There are people with penises whose brains are female, and people with clitorises whose brains are male. If your brain has developed in a manner that finds males attractive sexually, you will find males attractive sexually, regardless of what your genitals look like. If your brain is a brain that likes females, you will like females, no matter what your genitals look like. There is no (zero, nada, nil) evidence that sexual orientation is chosen.
So, non-accepting people, regardless of what your genitals look like, if you don’t like guys, don’t hit on them; if you don’t like girls, don’t try to hook up with them. Go for the people you like, and let others do the same. Be who you are, and let others do the same. It’s that simple.
Our psychology majors are typically headed for one of two careers: they want to help people as counselors or clinicians, or they want to extend out knowledge by becoming behavioral scientists. Both routes are potentially rewarding options, and both contribute importantly to society. Both also require ethics and integrity.
I’m thinking about this as I sit in a quiet office as our students enjoy Spring Break. The need for integrity does not begin when you enter the the counseling center or the laboratory and end when you leave. It’s a quality that you must possess and display all the time, or your work will not be taken seriously. Years ago a student explained to a a colleague of mine that she had to miss an important in-class exercise on the day before Spring Break (probably an exam, but it could have been anything) for a good reason (maybe an unchangeable doctor’s appointment, or a dead grandparent — the stated reason doesn’t really matter). Then she posted photos of herself and some friends at he beach (or on the ski slopes, or wherever) with a boast about taking off early for Break. Students left behind were none to happy about this, and of course the prof found out. She was thereafter known to us as Spring Break Girl — we doubted her word at every juncture, and I’m sure thought long and hard about offering positive recommendations on her behalf, as she could not be trusted.
I had a similar recent experience. A student indicated that for transportation-scheduling purposes she had to leave early for Break, resulting in her missing a class. Given that Break is scheduled at least a year in advance I am never happy about this kind of thing, but there’s little I can do about it (class is important, material covered is hard to make up, and attendance counts toward the grade, but students have their priorities). So, I acknowledged that leaving early is not a good idea, but wished her a good Break. Then that evening, hours after the class, I attended a local concert and who should be in the audience but… her. I don’t know why she chose to lie about her reason for missing class, but I will remember this incident.
Students: the opinion that others have of you is important. Academic success (doing well on exams, writing good papers, excelling on standardized tests) is important, and makes a difference to your future success. But so too does how people feel about you, and whether people trust you or not. I routinely ask myself one simple question before I write a positive letter of recommendation: “Is this student someone whom I could recommend to a friend?” Obviously if the student cannot write a simple sentence, or routinely fails exams, the answer is “no” and I will not write the letter. Similarly, no matter how academically gifted the student is, if the student has demonstrated that s/he is not to be trusted the answer is also “no.” If you’ll lie about something as trivial as the reason for missing a class, what else might you lie about? Therapy and science both require integrity; if you plan to go into either of these areas don’t squander the trust that others are willing to place in you.