Reaction Times

Reaction Times#

Background#

Reaction times are weird: they are slow, are stochastic and their distribution is not a standard one. Still, reaction times are measured extensively by psychophysicists and neuroscientists to study:

  • perception

  • attention

  • decision making

  • motor control

This module tries to give you an understanding of why reaction times are so interesting, and will delve deeper into a model to explain them. We will see that the weirdness of reaction times are a feature, that might underlie optimal decision making in an uncertain world. In this module, you will analyse self-generated reaction times.

Scope of this module#

You will prepare for the lectures by reading a comprehensive tutorial on the LATER model and by skimming a research paper on manual reaction times elicited by changes in sounds. During lectures, you will answer questions related to reaction times and the LATER model. During the application session, you will record your own reaction time data. You will analyze this data by creating reciprobit plots. You will write a brief report during the computer practical or make a presentation.

Learning goals#

*This assignment has been developed to support you to achieve the following learning outcomes: *

  • You understand and describe reaction times

  • You explain the LATER model

  • you gather reaction time data

  • You plot reaction times on a reciprobit scale

  • You write a brief report or present your findings

*These learning outcomes correspond to the following course learning goals. * At the end of this module, by focusing on reaction times, you will be able to:

  • describe psychophysical methods and analyse psychophysical data

  • describe and build elementary neural models

Product#

  • You will prepare for class by reading a tutorial on a model explaining reaction times (deadline a).

  • You will measure and analyse your own reaction times during the practical (deadline b).

  • You will produce a brief report or presentation during the practical (deadline c).

Instructions#

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  • Read up on reaction times. See section RTread.

  • Do your own reaction-time experiment. Depending on time available, you will do an experiment in the computer room, or you will use the data from the sound localization experiment. See section RTanalysis

  • Create a brief report or presentation. The report/presentation should contain all code and all figures made during the practical. The questions in this assignment should all be answered. The product should be a coherent story.

Reading Assignment#

The paper “The LATER model of reaction time and decision” (Noorani and Carpenter, 2016) is a tutorial on reaction times and how they can be accurately described by a simple model. This paper explains why reaction times are highly useful - not despite of their properties, but because of them. Please read Sections Abstract, 1-3, 9-10, and Appendix 8.1.1 of the paper.

After reading these pages you should be able to answer the following questions:

  • What are the properties of reaction times?

  • What are the properties of the LATER model and how can this model reaction times?

(TIP: while you’re reading make a structured summary)

To give you an example on how reaction time data can be used in an auditory task, please skim the paper “Reaction Time Sensitivity to Spectrotemporal Modulations of Sound” (Veugen et al., 2022). Skimming means: browse the Abstract and section Results - Reaction Time Task (including Fig. 2). After skimming this paper, you must be able to answer the following questions:

  • How do the sound parameters affect the (reciprobit plot of) reaction times?

  • If the LATER model holds, what do the findings imply about the model parameters?

If you would have more time to go through this paper, you would see that it also makes use of some concepts that are discussed during other modules in this course: e.g., transfer function, low-pass and bandpass filter, singular value decomposition, spectrum.

Mental chronometry#

The Donders Institute is named after Franciscus Cornelis Donders, who was interested in eye movements and mental chronometry (reaction times). If you are interested in the history of neuroscience, you might want to read this \href{https://www.ru.nl/donders/about-us/biography-donders/}{brief biography of F.C. Donders}.

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