Posts

  • Local Biases for Mental Model Updating

    Recently Isabella Sewell tackled the details of getting a study on line. This month the fruits of that effort were shared as a poster at the Neuroxchange 2021 undergraduate neuroscience on-line conference. Isabella was doing her undergraduate thesis with co-supervision by James Danckert and myself. James and I are interested in how we revise our models of the world in light of new information. We call this mental model updating, and we know that brain damage in either hemisphere can impair this skill. We have wondered if the two hemispheres might play different roles in this process. One classical division between the roles of the left and right hemispheres is for local and global processing. Isabella took this idea and developed a tool that we might use to probe hemispheric specializations. In her experiment a triangle points either up or down and the participant’s task is to predict the direction of the next triangle to be shown. For this task there is a global influence: a long time frame, repeating pattern of up-pointing more likely, alternating with down-pointing more likely. There is also a local bias in which the probability of the direction of the triangle is more likely to repeat. Experimentally you can mix these two biases in whatever proportion you propose. For this first assessment Isabella mixed these two distributions: the repetition probability and the global bias, in equal proportions. She found that participants were influenced by these biases, but in this cohort at least (healthy undergraduates) the local bias was all that we needed to predict partipants’ choices. Of course, we have only begun to explore some of the variations possible with this procedure. If you have ideas please feel free to share them with us (or Isabella). And if you want to know what comes next “watch this space.”

  • A Beginner's Guide to Writing Online Psychology Experiments

    A lot of the last term has been spent developing methods and procedures for moving behavioral studies on line. A lot of the responsibility for this transition has fallen on the shoulders of the graduate and undergraduate students and in the process we have experienced a lack of tutorial, step-by-step material. An undergraduate honors student working with James Danckert and myself, Isabella Sewell, was caught in this bind, and did yeoman’s work to get her study up and running this term. Then she decided to compound her efforts by being generous and recording detailed notes on the steps and tools she undertook so that others might have an easier time following her. While much of this will be specific to UWaterloo, and especially our lab group, there is still a lot of good general advice here and therefore we are sharing it here. If you just want to read her advice take a look the pdf. If you think it is something you would like to adapt to your own purposes you can also grab a docx version for editing. Please though remember to credit Isabella if you adapt her work. She put a lot of time and effort into this and deserves the acknowledgement. Thank you Isabella.

  • Cerebellum and Attention Work Accepted in Cortex

    Earlier I shared a pre-print of some work I had been involved in that was led by Chris Striemer at MacEwan University showing that cerebelllar lesions affect particular types of attentional tasks. This work has just been accepted in Cortex. Congratulations to Chris and his student Brandon. You can find the current pretty version at: paper web page

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