Cryptography

Why "cortical cryptography"? A fundamental question of Cognitive Neuroscience is the question of how information is represented in the neurons and synapses of the human brain. In cognitive psychology studies of learning and memory, we attempt to identify and control the type of information being acquired and we then observe the behavioral consequences that follow to verify the learning.

What is happening in-between the presentation of controlled information to the participant and the observation of their subsequent responses is essentially the encryption of information into the brain of the participant. So we can say that trying to understand the representation of information in neural systems is analogous to attempting to determine the encryption/decryption algorithm that the brain uses.

In basic research that we've been doing for awhile in the lab, I frequently find myself describing one of the goals of the research as identifying the operating characteristics of specific memory systems that we believe we can isolate. We attempt to find boundary conditions on the rate of learning, the applicability of the information (flexibility), the limitations on complexity of information to be acquired, the effect of passage of time (memory decay, forgetting).

Internally, I think of this as being something like a timing channel attack on this mysterious encryption algorithm.

From Wikipedia, http://en.wikipedia.org/wiki/Timing_attack

In cryptography, a timing attack is a side channel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms. Every logical operation in a computer takes time to execute, and the time can differ based on the input; with precise measurements of the time for each operation, an attacker can work backwards to the input.

I think I'd state the last bit a little differently -- I want to try to work out the characteristics (including time) of the encryption algorithm not to identify the input (we control the input), but to figure out the algorithm itself.

We are currently looking at perceptual-motor sequence learning, which we believe is largely supported by cortico-striatal circuit loops (from the basal ganglia to the cortex and back). There are a fair number of neurons in the circuit, but I have this hunch that if we can get some basic characteristics of the learning ability of the system, e.g., the bandwidth of the learning rate, that will rule out some possible encoding algorithms and constrain the set of plausible encryption algorithms.

Knowing versus Understanding

They aren't the same thing. As a while male, I know racism is wrong and I know constraining a woman's right to choose is wrong. But I cannot truly understand all the implications of these. Two examples from this week:

1. Amanda Marcotte at Pandagon talks briefly about a bill being considered in the Ohio legislature that would require women to get the permission of the sperm donor before getting an abortion. I know immediately this is a horrifying law and also that these types of laws generally do not get passed (except in South Dakota). But in writing about the practicalities, she points out that women will just get a male friend to vouch for being the father and:

Every woman reading this is taking a quick mental inventory of what man they could trust to do this without gloating about his power over you.

Yes. She's right and I didn't think of that right away. That's the difference between knowing and understanding. I know the proposed law is wrong, but I don't live with the knowledge that the people around me might democratically vote to take away my basic freedoms at any time, so I don't have this type of reflexive thinking. Althought I'd like to think I'd be the kind of person my female friends would think of as absolutely reliable in this spot. I wonder if they do.

2. Ta-Nehisi Coates has been mulling over the Gates' arrest in his own house in Cambridge. And also the death of Shem Walker in NYC. Two black men who were disrespectful to cops, but did nothing obviously wrong. One arrested, the other shot dead. I know being a cop is hard, they are almost always meaning well and I know it's best to always be respectful.

But I do not know what it's like to be a responsible, successful black person (man in particular, I suspect) and have to live one's whole life knowing this could be around the corner for you. One day you are part of the priviledged class -- you're successful, social responsible and doing it right. And the next day you're persecuted for your race. I feel like Dave Chappelle and Wanda Sykes have both done comedy on this theme. I find their routines funny and I feel like I "know" what they're talking about. But when TNC says he doesn't feel good with a cop like that holstering a gun around his kids, I realize I don't really understand.


Not understanding doesn't mean I can't be part of the conversation, nor that my opinion is totally invalid. Or even that I can't be right in an argument over policy even with somebody who really does understand. But as a priviledged white male, I have to remember that I don't really feel it the same way they do and that does matter sometimes.

Nativism, fiction, fantasy and politics.

There are two novels that can change a bookish fourteen-year old's life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs.
-- Kung Fu Monkey

A very common theme in fantasy is based around a world where some lucky fraction of the population has an innate ability to control magic. The same concept occurs in SF and comic book worlds with other kinds of special powers (especially mental powers like the Force). Usually the story begins with the protagonist discovering something that indicates that they are special and often then being contacted by a secret or semi-secret society for training and the story's adventures.

It's all fine and fun and the are a million ways to tell the story of growth and self-discovery from there. The meme's popularity suggests there's something pretty fundamental (adolescent?) about the idea of suddenly discovering that you are special and life isn't as ordinary and mundane as it seems.

But hiding under the concept is a very strong theory of nativism -- some people are born special. Those endowed with special powers can do things other cannot. This enables the story to be constructed as: something bad is going to happen and only the protagonist (you) can prevent it! If it didn't require specialness, then anybody could do it.

If the author needs to flesh out the world with other characters who share the specialness, then it will be necessary to figure out how to place the super-powered (magical) in the world. A question to face is then: why don't the super-powered run everything? What stops them from taking over the world and enslaving the non-powered? Often, this is set up as the thing the villian will do with their super-powers and the task of the protagonist is to stop them.

So you seem to find the super-powered ending up in certain kinds of roles. They might be hidden for fear of persecution (e.g., early X-men or Harry Potter) or perhaps they take on hidden, specialized advisory or problem-solving roles (Jedi in Star Wars, wizards in LoTR, most comic books). Some sense of duty or empathy towards the unpowered keeps them from exerting their dominance over everybody else. But it's also worth noting that the fiction worlds based on this idea are virtually never really democratic. At best they are democratic until trouble comes and then control is turned over to the super-powered elite to save everybody.

But even without evidence of magical superpowers, theories of nativist differences among people are everywhere as explanations of real-world phenomena. Given how much inequality exists in society, there's going to be a temptation to hypothesize that some fraction of the reason that some people end up at the high end is based on nativist differences (better IQ genes is the most popular version). Note that this is a lot like saying you're born with superpowers -- superpowers of intellect or related success-increasing traits.

I suspect this idea is what makes Randianism, objectivism and related forms of libertarian thinking so attractive to adolescents (and some never get over it). It's like discovering that you are Harry Potter, only instead of being a particularly powerful wizard, your power is in your ability to generally be on the winning side in our capitalist society. And if you want to push on that idea, well, why shouldn't the best and brightest own and run everything? Do you want imbeciles making policy decisions?

If you accept the logic of strong innate/nativist differences in ability, it's a tough logic to fight. One way is the "smart technocrat" concept, which is a lot like taking the best and brightest and making them the Jedi (wizards) of real society. Perhaps operating as stealthy bureaucrats who quiety solve problems and run things from behind the scenes (e.g., the Fed Reserve Chair).

This seems to map onto political approaches. In general, the Republican version says let competition work itself out and let the best and brightest have what they need to run the world the best. I would guess why they end up being the natural party of racists -- anybody who believes they are genetically superior to others wants the benefit of that superiority.

On the Democratic side, I think there's a number of different approaches to opposing the idea. The empathic "smart technocrat" (i.e., neoliberal) approach is one. A harder approach is to attack the underlying nativism directly.

In a generally laissez-faire society, competition (markets) will spread people out along a success continuum. The more successful will tend to have more resources and frequently as a result also have greater control over the political structure. If you are both strongly nativist and believe that success is well-predicted by innate differences, you should be ok with this since the better, smarter, more innately successful people will tend to be in charge.

But this fails if either innate differences are relatively small or success is strongly affected by non-innate factors (the phenotype does not always follow from the genotype). In either case, there is less reason to believe the set of genes among the successful is any more likely to predict future success than the sets of genes among the unsuccessful. From there, it is easy to argue in favor of democracy and for more equitable distribution of resources.

PGG

A recent letter to Nature looking at communal activities and whether/how/if they emerge from individual dynamics clued me in to some of the ideas in current research on this topic.

The model these authors use (and appears to be standard) is the Public Goods Game (PGG). In this, a group of actors each chooses to cooperate at some cost 'c' and the benefit of the cooperation is distributed across the whole group, both cooperators and defectors. Defecting is still the dominant strategy because you gain the benefit without paying the cost. The question is, how do you get a group to cooperate under these conditions?

One idea is that there are 'punishers' who identify and punish the defectors, making defecting no longer a viable strategy. The authors are tackling the question of how you get punishers into a community and come up with some conditions under which the most common stable equilibrium is a mix of cooperators and punishers.

Some points of basic difference in thinking:
* The PGG game is a nice extension to communal activities. And my idea of having enforced social norms seems to imply the existence of some sort of enforcer (punisher). How social norm enforcers get into the system seems more basic than my thinking.
* But it doesn't seem to consider the idea of competing communities. Those would seem to enforce a certain kind of punishment as well. If your community doesn't cooperate and gain the benefits, a neighboring community (tribe) will out-compete you.
* The PGG game also implicitly leaves the D-D cell as a very bad thing. I think this is the typical assessment, but it points out to me that maybe it's not that simple. In these games Defect is the opposite of Cooperate. But Compete is also the opposite the Cooperate. It's not synonymous with Defect, but it overlaps a lot. And groups who compete get global social benefits as well under certain conditions.
* Which leads me to think that Symmetry is maybe the key idea for me. You don't just need C-C outcomes, but the idea is that you want C-C and D-D outcomes and avoid the C-D cells. If you can make the case for this, then homogeniety of decision processes becomes high utility.
* The PGG model (and maybe most game theory) doesn't really dig into the idea of the individual decision arising from a series of cognitive operations. Nor is there any learning. I suppose you could say that learning to become a cooperator from being a defector is identical to replacement in their models. But if there are environmental context effects on learning, these might affect that process (i.e., change the replacement function). Both the idea of homogenizing cognition across individuals and the effect of reinforcement learning in symmetry-dominated groups (which will lead to C being rewarded over D and increase altruism) require doing some cognitive psychology on the actors.
* The issue of the virtuous D-D conditions may be complex. It seems to me to be the place where capitalism occurs -- competition for ideas, information, valuation seems to emerge from D-D interactions. I have a strong intuition that a high percentage of dyadic capitalist interactions are D-D. E.g., prices set on supply/demand rather than value to the purchaser, any "trading" that is based on estimates of future value (the transaction should only occur when the seller and buyer have different estimates). Is this an unusual idea? How common or useful are virtuous D-D interactions versus C-C interactions in capitalist interactions (buy-and-hold long from an IPO or bond is a C-C, you cooperate in providing capital, there's a communal gain from the investment growth and the rewards benefit all participators).
* The the communal action model of the PGG, D-D can be better than C-D if the group action has some non-linearity to it, e.g., it requires a certain number of C actors to gain the benefit. Then if some Cooperate but not enough to gain the benefit, it's a communal loss. This is a very minor version of the "virtuous D-D" where D-D > C-D.


The abstract from the Nature paper:

Social diversity promotes the emergence of cooperation in public goods games

Francisco C. Santos¹, Marta D. Santos² & Jorge M. Pacheco²

1. Institut de Recherches Interdisciplinaires et de Développements en Intelligence Artificielle (IRIDIA), Computer and Decision Engineering Department, Université Libre de Bruxelles, B-1050 Brussels, Belgium
2. ATP-group, Centro de Fisica Teórica e Computacional (CFTC) and Departamento de Física da Universidade de Lisboa, Complexo Interdisciplinar, Av. Prof. Gama Pinto 2, 1649-003 Lisboa, Portugal

Correspondence to: Jorge M. Pacheco² Correspondence and requests for materials should be addressed to J.M.P. (Email: pacheco@cii.fc.ul.pt).

Top of page

Abstract

Humans often cooperate in public goods games^{1, 2, 3} and situations ranging from family issues to global warming^{4, 5}. However, evolutionary game theory predicts^{4, 6} that the temptation to forgo the public good mostly wins over collective cooperative action, and this is often also seen in economic experiments⁷. Here we show how social diversity provides an escape from this apparent paradox. Up to now, individuals have been treated as equivalent in all respects^{4, 8}, in sharp contrast with real-life situations, where diversity is ubiquitous. We introduce social diversity by means of heterogeneous graphs and show that cooperation is promoted by the diversity associated with the number and size of the public goods game in which each individual participates and with the individual contribution to each such game. When social ties follow a scale-free distribution⁹, cooperation is enhanced whenever all individuals are expected to contribute a fixed amount irrespective of the plethora of public goods games in which they engage. Our results may help to explain the emergence of cooperation in the absence of mechanisms based on individual reputation and punishment^{10, 11, 12}. Combining social diversity with reputation and punishment will provide instrumental clues on the self-organization of social communities and their economical implications.

IPDG

In a standard "prisoner's dilemma" game, the payoff matrix is set up to make Defection the dominant strategy. The concept captures a lot of situations where you could choose to do something helpful to others (= Cooperate, in the IPDG) and if everybody cooperates, everybody wins. But in many of these situations, if everybody else is cooperating, you can personally maximize by Defecting. You gain the benefits of everybody else cooperating, but you don't bear the cost of cooperating.

Example: picking up litter. If everybody does it, the environment gets clean. But if everybody else is doing it, you can stop doing it and get the benefit of the clean environment (somebody else will pick it up) without doing the work. But, if everybody starts to Defect and you still Cooperate, now you get all the cost and no real benefit.

An interesting payoff matrix looks something like:
Coop/Coop: +1/+1
Defect/Coop: +2/-5 (and vice versa)
Defect/Defect: -1/-1

In these kinds of games, the math is pretty clear that absent external knowledge of what the other actor will do, you are best served to Defect. In iterated games where you have some knowledge over time of what the other actor does, the tit-for-tat strategy is optimal (do to the other person whatever they did to you last, but cooperate on the first trial).

The math implies a puzzle about why people engage in altruism -- why cooperate at all? Are people not rational? Or do they expect some return from their reputation -- if you cooperate and re-engage the same person later and they remember you, perhaps they'll cooperate back and you'll get a return on your invested cost. The math seems to depend on the probability of reciprocation.

Douglas Hofstadter, however, points out another reason to cooperate which he calls Superrationality. The idea is that if you know your opponent/partner is extremely insightful, you might both be able to reason in a way that leads to similar conclusions. E.g., you both realize the game is Defect dominant, so you'll both initially think to defect. But you both also realize that given that you will both choose the same option, you could safely cooperate knowing the other person will also find the reason to cooperate and you'll get to the C-C outcome.

Whether people actually think that way is one thing, but it does point out the value of symmetry in the game. Any time 2 actors choose the same action, the result is "fair" to both of them and optimal for them combined if they both cooperate. The payoff matrix described above is also designed to maximize the joint outcome in the C-C cell.

If we extend the IPDG beyond two-person interactions to think of the welfare of a collection of individuals (who each interact in pairs), it's clear that maximizing the community welfare is done by maximizing the number of C-C interactions. This is a situation where you personally maximize your utility by Defecting, but your community is maximized by Cooperating.

If we imagine a large number of competing communities out in the world, what is the optimal way for a community to out-compete other communities?

Two things that will help a lot are: (1) social norms defined in the community that encourage/require cooperation as much as possible and (2) in-group/out-group biases.

On (1), communities with strong social norms that require people to set aside personal gain and cooperate for communal benefit will out-compete more individualistic communities. In fact, for the specific payoff matrix above, you don't strictly need a cooperation/altruism directive, you can actually get the communal benefit mainly through symmetry. If you have a very homogeneous set of actors (who all think alike), they should tend to come to cooperate/defect decisions the same way and tend to end up in the C-C or D-D cells (which are community maximizing). Also, if there's any learning in the actors, experience with only C-C or D-D interactions will tend to reinforce Cooperating over Defection and the community will move towards general altruism.

On (2), it's obvious that if you want your community to out-compete other communities, you want to maximize Cooperation (altruism) within your community, but personally maximize utility outside and Defect (or at best tit-for-tat).

Curiously, this seems to imply that if you have many communities competing over a long period of time and success is related to how well your community structure maximizes outcomes, communities that construct very strong social norms, homogeneous thinking and strong out-group biases should tend to win. Does this provide insight into the prevalance of groups that organize around religions that are particularly controlling, nationalism (and strong cultural expectations) and even racism?

Thoughts on gender differences in math

Reminded by this link:
http://blogs.discovermagazine.com/80beats/2009/06/02/more-evidence-that-girls-kick-ass-at-math-just-like-boys/

To copy the following older post off the lab blog (from 10/4/2007):

I vented about this at lab meeting the other day. I now think it's time to actually organize some information on it because the idea seems more pernicious than I initially realized.

I think of this as the "Larry Summers" hypothesis, although this is actually a bit inaccurate (although people would probably recognize it by that name). The core idea is that a reason women are underrepresented at the highest levels of success in math and science (e.g., faculty positions at top universities) is that the distributions of inherent ability betwen men and women are different. The mean inherent ability may be identical, but greater variance in the male distribution puts more men in the extremes of high and low ability. Thus at the highest levels of success, you would expect to find less women because there are fewer women at the very upper end of the distribution.

This seems like a question of science and statistics, but there's a significant danger here. If the core hypothesis is believed, it argues against gender-based affirmative action at top universities. If the existing difference in representation of men and women in top universities is based on a genetic difference, increasing representation women will actually make those departments stupider on average.

The alternate hypothesis is that the existing differential representation is due to cultural (social, environmental) factors that can be ameliorated by affirmitive action policies aimed at overcoming a historical cultural bias against women in these fields.

So we have a particularly difficult situation: a scientific question that is very hard to assess that has a direct and immediate policy impact. My personal opinion is that in these cases, it is important to weigh the costs of error. If we have to make a binary policy decision (affirmative action, yes or no) that will be based on an evaluation of the balance of unclear evidence, which error is more costly? Is more damage done by in appropriately implementing or eliminating affirmative action? I will note that this kind of consideration is broadly unpopular with scientists who see themselves as pure seekers of truth. But I'm not going to argue that philosophical point here since this particular theory can just be evaluated on a balance of evidence basis and there doesn't seem to be much to it.

Some background
The original Summers situation is described evenhandedly on Wikipedia.

An excerpt:

Controversy

Another study performed by the American Psychological Association in response to the book The Bell Curve, which investigated the difference in intelligence between different social classes (strongly correlated with race in the U.S.), determined (as did the authors of the book) that the studies available in 1995 showed no major difference between males and females in regard to IQ scores.[24]

In January 2005, Lawrence Summers, president of Harvard University, unintentionally provoked a public controversy when MIT biologist Nancy Hopkins leaked comments he made at a closed economics conference at the National Bureau of Economic Research.[25] [26] [27] In analyzing the disproportionate numbers of men over women in high-end science and engineering jobs, he suggested that, after the conflict between employers' demands for high time commitments and women's disproportionate role in the raising of children, the next most important factor might be the above-mentioned greater variance in intelligence among men than women, and that this difference in variance might be intrinsic,[28], adding that he "would like nothing better than to be proved wrong". The controversy generated a great deal of media attention, forced Summers to make a number of apologies, and led Harvard to commit $50 million to the recruitment and hiring of women faculty.[29]

In May 2005, Harvard University psychology professors Steven Pinker and Elizabeth Spelke debated "The Science of Gender and Science".[30]

In July 2006, Stanford University neurobiologist Ben Barres, a transsexual man, wrote a provocative piece in Nature on his own experiences as both a male and female scientist.[31] Barres argued that prior to transition, he had succeeded as a female despite pervasive sexism. Barres wrote that numerous studies show female scientists are consistently rated lower than their male counterparts with the same levels of productivity and credentials.

In 2006, Danish psychologist Helmuth Nyborg was asked to vacate his position at Aarhus University after publishing a paper in Personality and Individual Differences that showed an 8 point IQ difference in favour of men.Nyborg, Helmuth (2005). "Sex-related differences in general intelligence g, brain size, and social status". Personality and Individual Differences 39: 497-509.

Summers in an economist. Where did he get this idea about variability? I'm not sure, but apparently this idea has some "mainstream" support in Psychology.

Baumeister's 2007 APA address
Stephen Pinker taking this position in a debate with Liz Spelke

There's a lot of interesting stuff here. But I was really captured by the similarities of the Pinker/Baumeister argument because they have the same flaws that seemed pretty obvious to me. I actually do hesitate when it seems like a smart person is arguing something transparently stupid. A plausible alternate hypothesis is that I'm wrong or misunderstanding something important. So pointing out the core problems here may help us evaluate which hypothesis is more plausible (they're being stupid or I am).

The variance hypothesis
I included the links so that you could check my account of the hypothesis, but it's not really complicated. There are plenty of data that say men are overrpresentated at both tails of the distribution. You could probably argue about the data, or tackle the question of what is being distributed, IQ? intelligence? success? ability? Success is probably the best description (although all those constructs co-load) and I'm happy to stipulate the data are what they are for the purpose of evaluating the rest of the argument.

The problem is the inference that the differential variability is inherent, i.e., it's based on a significant genetic contribution. The obvious alternate hypothesis is that the differential representation in the tails is predominantly cultural or societal based on differential treatment of men/women (boys/girls).

In case you're wondering, a simple way you get differential representation in the tails is via feedback loops. Let's say individuals vary in ability and some small percentage have the ability to become geniuses if provided with effective teaching/instruction/training (note this is a fairly nativist argument itself and not the only one). E.g., exhibiting ability -> attention & more teaching -> greater ability -> more specialized teaching... etc. until you push somebody out into the very upper tail of ability/success. If this trait was equally distributed across genders, but there was even a slightly lower chance that the feedback loop gets started for women then men, you'll end up with women underrepresented in the tail due to cultural differences.

Is that plausible? Maybe. There is an abundant evidence that men and woman (boys and girls) are treated differently at least. What's the evidence that the overrepresentation in the tails is genetically based (inherent)?

There isn't any actually. Baumeister references greater variability in height among men, but not only can I not find any source for that (I looked up average height charts and the distributions look roughly identical) but you might even expect SD to go up with mean (men are taller).

Very weirdly, both Baumeister and Pinker argue that men have been selected for greater risk taking historically as if that was related. Baumeister also argues that men are under greater selection pressure to pass their genes along (fewer men have passed their genes through time than women apparently). But neither argument is remotely relevant to producing greater variability in success. In fact, greater selection should produce less variability (as any remotely clueful evolutionary psychology should know) not more. You could use either of these to argue why you think men should be smarter on average (they aren't) but neither is related to increased variability.

Pinker gives us one pseudo-shred of data: "And biologists since Darwin have noted that for many traits and many species, males are the more variable gender."

So there's your alternative hypotheses to consider: men are the more variable gender or social/cultural affects influence the degree to which women acheive upper-tail success.

Pinker's talk is the far less egregious of the two, but the absence of consideration of social or cultural effects is still staggering. He spends a considerable amount of time documenting existing differences between genders to prove that there are some. I don't believe there are reasonable people who disagree with that, but it still doesn't mean success/ability is genetically determined. It doesn't even mean all those differences are genetic/inherent.

There are a whole lot of examples of this in his talk, but here's my current favorite as a parent of a 13yo girl who is in an accelerated math track in high school:

Fifth, mathematical reasoning. Girls and women get better school grades in mathematics and pretty much everything else these days. And women are better at mathematical calculation. But consistently, men score better on mathematical word problems and on tests of mathematical reasoning, at least statistically. Again, here is a meta analysis, with 254 data sets and 3 million subjects. It shows no significant difference in childhood; this is a difference that emerges around puberty, like many secondary sexual characteristics. But there are sizable differences in adolescence and adulthood, especially in high-end samples. Here is an example of the average SAT mathematical scores, showing a 40-point difference in favor of men that's pretty much consistent from 1972 to 1997. In the Study of Mathematically Precocious Youth (in which 7th graders were given the SAT, which of course ordinarily is administered only to older, college-bound kids), the ratio of those scoring over 700 is 2.8 to 1 male to female. (Admittedly, and interestingly, that's down from 25 years ago, when the ratio was 13-to1, and perhaps we can discuss some of the reasons.) At the 760 cutoff, the ratio nowadays is 7 males to 1 female.

"...this is a difference that emerges around puberty, like many secondary sexual characteristics." Can Dr. Pinker seriously not consider the possibility that the development of secondary sexual characteristics would increase the differential social/cultural treatment of young girls? Does he think the only thing that changes for girls at puberty is the concentration of hormones in the body? wtf?

And in his own data here, he admits the number of girls in the upper tail has changed dramatically over the recent period of greater concern about gender issues and more gender-based affirmative action.

So re-consider the binary policy question of "gender-based affirmitive action, yes or no?" as it is impacted by this very difficult scientific question, "is the observed increased variability in success/ability of men relative to women based on inherent genetic factors or environmental/cultural factors?" And you'll see why I'm so thorougly annoyed about this.

Larry Summers was President of Harvard at the time he suggested this was a major cause of differential representation of men and women on the faculty. Is it still safe to ignore the policy implications of weak science?

P.S. There is one claim in the midst of Pinker's laundry list aimed at proving men and women are inherently different that I should probably go find better data on.

Seventh, a lack of differential treatment by parents and teachers. These conclusions come as a shock to many people. One comes from Lytton and Romney's meta-analysis of sex-specific socialization involving 172 studies and 28,000 children, in which they looked both at parents' reports and at direct observations of how parents treat their sons and daughters — and found few or no differences among contemporary Americans. In particular, there was no difference in the categories "Encouraging Achievement" and "Encouraging Achievement in Mathematics."

There is a widespread myth that teachers (who of course are disproportionately female) are dupes who perpetuate gender inequities by failing to call on girls in class, and who otherwise having low expectations of girls' performance. In fact Jussim and Eccles, in a study of 100 teachers and 1,800 students, concluded that teachers seemed to be basing their perceptions of students on those students' actual performances and motivation.

A few basic points of reality: First, math and science teachers at the middle and high school level aren't predominantly female (elementary school teachers are and they aren't dupes, but they are influenced by cultural expectations). Second, he's apparently never heard of the Implicit Attitudes Test which shows marked discrepancies between intentions and actual bias. People regularly report doing their best to be non-biased, but are not able to consistently hold to it. The fact that parents report they mean to be as encouragng to girls in school does not guarantee that they are. And the fact that teachers believe they are responding to their perceptions of student interest does not mean their perceptions aren't influenced by a bias to see women/girls as less interested in math/science material (which, incidentally, is a feedback loop that would push women away from the tails and back towards the mean of the distribution).

BTW, the best way to see the patently obvious difference in treatment of girls/boys in school is to look at how they treat each other. You get a better picture of the cultural bias bleeding through because they don't have the frontal lobes to effectively inhibit the implicit attitudes they pick up from the world. But I should get some actual data on this.

Research Methods

I teach Research Methods in Psychology. The class is structured to be a lot of work for the undergraduates at NU. It is often viewed with dread by the students. There's a lot of writing and the material seems like it might be pretty dry.

So I was jealous when I see Brad DeLong and Paul Krugman occasionally post their class syllabi online to their blogs. Their classes look interesting, but I wouldn't post a Research Methods syllabus online. Who'd want to read that on purpose?

Reflecting on this, I think maybe I'm doing it wrong. People actually like science. There are science columns in all sorts of weeklies, in newspapers, on the "most emailed" list at Yahoo or other news aggregators. And a lot of that science is not so good. People should be better at distinguishing the good stuff from the weak stuff and in theory, Research Methods is the class where they would learn to do this.

I haven't figured out how to do it right yet, though. I'm not posting the syllabus. Mythbusters on the Discovery Channel seems to manage to teach some science and get people to watch on purpose. I can't think of a way to blow stuff up in Research Methods, though.

Newspapers and colleges

Title copied from DeLong:
http://delong.typepad.com/sdj/2009/03/newspapers-and-colleges.html

Who linked the key idea from Kevin Carey:
http://chronicle.com/weekly/v55/i30/30a02101.htm

Question: Are colleges in trouble the way newspapers are in trouble? Will digital access to content wreck their business model?

My answer: No.

First, if you are teaching such that the YouTube or iTunes videos of your lectures are equivalent to taking the class, something seems to be going wrong. This is especially true if you have a reasonably small class size. Students know how to read. If the written material is sufficiently unclear that you need to then come to class and explain it, maybe you need a better text. The lecturer should be adding value over a good text one way or another.

In big classes where interaction is limited, the lecturer can add value by shaping the information from the text (emphasis/paraphrasing). Because of writing/printing lags, we can assume the text isn't necessarily up to date in every way. Maybe places where the lecturer challenges a claim of the text signals areas of interesting debate. But what about fields where the basic information doesn't change much year to year (e.g. calculus, but not psychology)? And what happens when students get their textbooks from a Kindle that can update more rapidly?

There's a learning and memory question in there: is it better to read, hear or read+hear for long-term memory of the content. The last of these implies multiple repetitions which is better. But is podcast+text < lecture+text? If not, maybe intro classes do end up changing a lot with technology.

Second, there are definitely classes and probably also extracurricular activities that depend entirely on discussion and face-to-face interactions. These become more available and potentially more important as the big intro classes become easier. One good example from the Psych department at NU is that a lot of our Psych majors get to participate directly in psychological research via an independent study. Neither Psychology nor scientific methods are as generally well understood as they could be and hands-on work in a lab is not only fun, but very valuable in both of those domains.

Third, there is a lot more to being at a college than just sitting in lectures. I'm not entirely convinced that the social networking being done outside the classroom isn't occasionally as valuable (or more) than the facts being absorbed from the courses taken. I think some professors/lectures forget this on occasion. We're a small piece of undergraduate education even beyond the fact that each of our classes is just one in the midst of many that students take.

Teaching and technology

Comments on other people's blogs feel like they disappear too quickly. I can keep better track of my thoughts and maybe even share them here. FWIW, the name comes from something else altogether but I like the phrase.

The motivation to set this up is to describe some ideas I've recently had about teaching. The idea and new things I'm trying in teaching were really all inspired by Brad DeLong's blog. Although our fields are different (economics for him, cognitive neuroscience and psychology for me), we share a certain technophilia and interest in how technological change influences information transmission and the consequences of those changes.

The current teaching experiment is using podcasts as part of my teaching of Research Methods in Psychology. When I first mentioned my idea to the academic technology staff here at Northwestern University, they assumed I wanted to record my lectures. No, that's not the idea. My idea is that as video is easy and cheap, why are we lecturing to students? In my own teaching, I spend part of the time talking at the students (lecturing) and part in more interactive discussions and exercises. The latter part of that seems to be where face-to-face interaction is actually useful.

So the idea is to pre-record a podcast of the 10-15m I used to spend at the beginning of the class lecturing based on the text. The lecture was to emphasize parts, de-emphasize other parts, paraphrase and review content they were supposed to have already read. This was followed by analysis and discussion of good and bad research examples. If they pre-watch the lecture part, I can spend the whole class on the interactive parts. In theory, this may enhance education, but in practice - ?

The seed for the core idea comes from DeLong's economic history note on Universities:
http://delong.typepad.com/sdj/2008/08/why-are-we-here.html
Excerpted:

The Pre-Gutenberg University:

• Universities have their origins in the medieval need of the powerful to train theologians (for the church) and to train judges (for the emperor and the kings of France, England, Castile, and other kingdoms.
• A manuscript hand-copied book back in 1000 cost roughly the same share of average annual income as $50,000 is today.
• Hence if you have a "normal" college--eight semesters, four courses a semester--and demand that people buy and read one book a course, you are talking the equivalent of $1.6M in book outlay. Can't be done.
• Hence you assemble the hundred or so people who want to read Boethius's The Consolation of Philosophy in a room, and have the professor read to them--hence lecture, lecturer, from the Latin lector, reader--while they frantically take notes because they are likely to never see a copy of that book again once they are out in the world administering justice in Wuerzburg or wherever...

Once the printing press arrives, book prices drop and yet, universities and lecturing persists.

In theory, classroom lecturing persists because the professor is adding something not immediately available just from the written text. Some of that comes from the ability for students and professors to interact in the classroom. Some of it may come from the immediacy of having somebody standing in front of you telling you the information -- maybe that's better for learning and memory than reading in some cases? Maybe the lecturer can re-phrase, re-act to the audience and provide better emphasis?

The podcast+more interaction theory is based on the idea that hearing it is a good supplement to reading it and interaction is useful and worth spending as much time as possible on.