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Tuesday, November 10, 2020

Is it possible to write an honest psycholinguistics paper?

I'm teaching a new course this semester: Case Studies in Statistical and Computational Modeling. The idea is to revisit published papers and the associated data and code from the paper, and p-hack the paper creatively to get whatever result you like. Yesterday  I demonstrated that we could conclude whatever we liked from a recent paper that we had published; all conclusions (effect present, effect absent) were valid under different assumptions! The broader goal is to demonstrate how researcher degrees of freedom play out in real life.

Then someone asked me this question in the class:

Is it possible to write an honest psycholinguistics paper? 

The short answer is: yes, but you have to accept that some editors will reject your paper. If you can live with that, it's possible to be completely honest. 

Usually, the  only way to get a paper into a major journal is to make totally overblown claims that are completely unsupported or only very weakly supported by the data. If your p-value is 0.06 but  you want to claim it is significant, you have several options: mess around with the data till you push it below 0.05. Or claim "marginal significance". Or you can bury that result and keep redoing the experiment till it works. Or run the experiment till you get significance. There are plenty of tricks out there.

 If you got super-duper low p-values, you are on a good path to a top publication; in fact, if you have any  significant p-values (relevant to the question or not) you are on a good path to publication, because reviewers are impressed with p<0.05 somewhere, anywhere, in a table. That's why you will see huge tables in psychology articles, with tons and tons of p-values; the sheer force of low p-values spread out   over a gigantic table can convince the  reviewer to accept the paper, even though  only a single cell among dozens or hundreds in that table is actually testing the hypothesis. You can rely on the fact that nobody will think to ask whether power was low (the answer is usually yes), and how many comparisons were done.

Here are some examples of successes and failures, i.e., situations where we honestly reported what we found and were either summarily rejected or (perhaps surprisingly) accepted.

For example, in the following paper, 

Shravan Vasishth, Daniela Mertzen, Lena A. Jäger, and Andrew Gelman. The statistical significance filter leads to overoptimistic expectations of replicabilityJournal of Memory and Language, 103:151-175, 2018.

I wrote the following conclusion:

"In conclusion, in this 100-participant study we dont see any grounds for claiming an interaction between Load and Distance. The most that we can conclude is that the data are consistent with memory-based accounts such as the Dependency Locality Theory (Gibson, 2000), which predict increased processing difficulty when subject-verb distance is increased. However, this Distance effect yields estimates that are also consistent with our posited null region; so the evidence for the Distance effect cannot be considered convincing." 

Normally, such a tentative statement would lead to a rejection. E.g., here  is a statement  in another paper that led to a desk rejection (same editor) in the same journal where the above paper was published:

"In sum, taken together, Experiment 1 and 2 furnish some weak evidence for an interference effect, and only at the embedded auxiliary verb."

We published the above (rejected) paper in Cognitive Science instead.

In another example, both the key effects discussed in this paper would   have technically been  non-significant had we done a frequentist analysis.  The fact that we interpreted the Bayesian credible intervals with reference to a model's quantitative predictions doesn't change that detail. However, the paper was accepted:

Lena A. Jäger, Daniela Mertzen, Julie A. Van Dyke, and Shravan Vasishth. Interference patterns in subject-verb agreement and reflexives revisited: A large-sample studyJournal of Memory and Language, 111, 2020.

In the above paper, we were pretty clear about the fact that we didn't manage to achieve high enough power even in our large-sample study: Table A1 shows that for the critical effect we were studying, we probably had power between 25 and 69 percent, which is not dramatically high.

There are many other such examples from my lab, of papers accepted despite tentative claims, and papers rejected because of tentative claims. In spite of the  rejections, my plan is to continue telling the story like it is, with a limitations section. My hope is that editors will eventually understand the following point:

Almost no paper in psycholinguistics is going to give you a decisive result (it doesn't matter what the p-values are). So, rejecting a paper on the grounds that it isn't reporting a conclusive result is based on a misunderstanding about what we learnt from that paper. We almost never have conclusive results, even when  we claim we do. Once people realize that, they will become more comfortable accepting more realistic conclusions from data. 

Wednesday, September 16, 2020

Zoom link for my talk: Twenty years of retrieval models

Here is the zoom registration link to my talk at UMass on Sept 25, 21:30 CEST (15:30 UMass time).
Title: Twenty years of retrieval models
Abstract:
After Newell wrote his 1973 article, "You can't play twenty questions with nature and win", several important cognitive architectures emerged for modeling human cognitive processes across a wide range of phenomena. One of these, ACT-R, has played an important role in the study of memory processes in sentence processing. In this talk, I will talk about some important lessons I have learnt over the last 20 years while trying to evaluate ACT-R based computational models of sentence comprehension. In this connection, I will present some new results from a recent set of sentence processing studies on Eastern Armenian.
Reference: Shravan Vasishth and Felix Engelmann. Sentence comprehension as a cognitive process: A computational approach. 2021. Cambridge University Press. https://vasishth.github.io/RetrievalModels/ Zoom registration link:
You are invited to a Zoom webinar. When: Sep 25, 2020 09:30 PM Amsterdam, Berlin, Rome, Stockholm, Vienna Topic: UMass talk Vasishth
Register in advance for this webinar: https://zoom.us/webinar/register/WN_89F7BObjSwmxnK6DRC9fuQ
After registering, you will receive a confirmation email containing information about joining the webinar.

Tuesday, September 15, 2020

Twenty years of retrieval models: A talk at UMass Linguistics (25 Sept 2020)

I'll be giving a talk at UMass' Linguistics department on 25 September, 2020, over zoom naturally. Talk title and abstract below:
Twenty years of retrieval models
Shravan Vasishth (vasishth.github.io)
After Newell wrote his 1973 article, "You can't play twenty questions with nature and win", several important cognitive architectures emerged for modeling human cognitive processes across a wide range of phenomena. One of these, ACT-R, has played an important role in the study of memory processes in sentence processing. In this talk, I will talk about some important lessons I have learnt over the last 20 years while trying to evaluate ACT-R based computational models of sentence comprehension. In this connection, I will present some new results from a recent set of sentence processing studies on Eastern Armenian.
Reference: Shravan Vasishth and Felix Engelmann. Sentence comprehension as a cognitive process: A computational approach. 2021. Cambridge University Press. https://vasishth.github.io/RetrievalModels/

Monday, September 07, 2020

Registration open for two statistics-related webinars: SMLP Wed 9 Sept, and Fri 11 Sept 2020

As part of the summer school in Statistical Methods for Linguistics and Psychology, we have organized two webinars that anyone can attend. However, registration is required. Details below

Keynote speakers

  • Wed 9 Sept, 5-6PM:Christina Bergmann (Title: The "new" science: transparent, cumulative, and collaborative)
    Register for webinar: here
    Abstract: Transparency, cumulative thinking, and a collaborative mindset are key ingredients for a more robust foundation for experimental studies and theorizing. Empirical sciences have long faced criticism for some of the statistical tools they use and the overall approach to experimentation; a debate that has in the last decade gained momentum in the context of the "replicability crisis." Culprits were quickly identified: False incentives led to "questionable research practices" such as HARKing and p-hacking and single, "exciting" results are over-emphasized. Many solutions are gaining importance, from open data, code, and materials - rewarded with badges - over preregistration to a shift away from focusing on p values. There are a host of options to choose from; but how can we pick the right existing and emerging tools and techniques to improve transparency, aggregate evidence, and work together? I will discuss answers fitting my own work spanning empirical (including large-scale), computational, and meta-scientific studies, with a focus on strategies to see each study for what it is: A single brushstroke of a larger picture.
  • Fri 11 Sept, 5-6PM: Jeff Rouder Title: Robust cognitive modeling
    Register for webinar: here
    Abstract: In the past decade, there has been increased emphasis on the replicability and robustness of effects in psychological science. And more recently, the emphasis has been extended to cognitive process modeling of behavioral data under the rubric of “robust models." Making analyses open and replicable is fairly straightforward; more difficult is understanding what robust models are and how to specify and analyze them. Of particular concern is whether subjectivity is part of robust modeling, and if so, what can be done to guard against undue influence of subjective elements. Indeed, it seems the concept of "researchers' degrees of freedom" plays writ large in modeling. I take the challenge of subjectivity in robust modeling head on. I discuss what modeling does in science, how to specify models that capture theoretical positions, how to add value in analysis, and how to understand the role of subjective specification in drawing substantive inferences. I will extend the notion of robustness to mixed designs and hierarchical models as these are common in real-world experimental settings.

Jeff Rouder's keynote address at AMLaP 2020: Qualitative vs. Quantitative Individual Differences: Implications for Cognitive Control

 For various reasons, Jeff Rouder could not present his keynote address live. 

Here it is as a recording

Qualitative vs. Quantitative Individual Differences: Implications for Cognitive Control

Jeff Rouder (University of Missouri) rouderj@missouri.edu

Consider a task with a well-established effect such as the Stroop effect. In such tasks, there is often a canonical direction of the effect—responses to congruent items are faster than incongruent ones. And with this direction, there are three qualitatively different regions of performance: (a) a canonical effect, (b) no effect, or (c) an opposite or negative effect (for Stroop, responses to incongruent stimuli are faster than responses to congruent ones). Individual differences can be qualitative in that different people may truly occupy different regions; that is, some may have canonical effects while others may have the opposite effect. Or, alternatively, it may only be quantitative in that all people are truly in one region (all people have a true canonical effect). Which of these descriptions holds has two critical implications. The first is theoretical: Those tasks that admit qualitative differences may be more complex and subject to multiple processing pathways or strategies. Those tasks that do not admit qualitative differences may be explained more universally. The second is practical: it may be very difficult to document individual differences in a task or correlate individual differences across task if these tasks do not admit qualitative individual differences. In this talk, I develop trial-level hierarchical models of quantitative and qualitative individual differences and apply these models to cognitive control tasks. Not only is there no evidence for qualitative individual differences, the quantitative individual differences are so small that there is little hope of localizing correlations in true performance among these tasks.