PEBL Blog

Addition Flashcard Game

2012-02-16T10:03:00.000-05:00

Psychologists have used various math tasks as a measure of mental abilities and a manipulation of mental workload for years. This includes various math tasks in the PEBL Test battery, as well as things like backward arithmetic and the operation span task. But this post shows a small little 'flashcard' game I made for my daughter to help her practice adding. The goal was simple:

A Multi-option choice task

2012-01-15T14:41:00.000-05:00

Recently, a user was interested in creating a similarity judgment task where the participant would see one color shade, and then be presented with six color shades--the correct one plus five similar foils, and have to choose the proper target. This basic type of task can probably be considered a "Match to sample" task that goes back at least to Skinner and the behaviorists. It was useful to

PEBL Programming Tutorial VI: Drawing Shapes

2012-01-01T06:00:00.000-05:00

This is Part VI of a series of tutorials on PEBL First | Previous | Next One of the hidden and powerful capabilities of PEBL is its ability to draw shapes. Many times, if you want to create some geometric shape as a stimulus, it is fine to do so in a image editing program such as photoshop, and then import the rasterized image into PEBL. But you can usually save yourself a lot of hassle

PEBL Programming Tutorial V: Iteration

2011-12-18T06:00:00.000-05:00

This is Part V of a series of tutorials on PEBL First | Previous | Next The previous tutorials showed how to do some simple but important things required for an experiment, such as displaying a stimulus or collecting a response. Another important part of almost every experiment is repetition. For example, you may have multiple questions you ask, or multiple trials where you want to do

PEBL Programming Tutorial IV: Redefining Functions

2011-12-04T06:00:00.000-05:00

This is Part IV of a series of Tutorials on PEBL First | Previous | Next The Print() and Print_() functions can be extremely useful in PEBL for debugging. You can print out the state of particular variables at different points during execution of a program, and help track down errors. But when using PEBL on windows, or from the launcher, this well get saved to a file you can examine.

PEBL Programming Tutorial III: collecting responses

2011-11-20T06:00:00.000-05:00

This is Part III of a series of tutorials on PEBL First | Previous | Next The previous tutorial described how to display basic text stimuli on the screen. Most experiments require both a stimulus and a response. The simplest way to collect responses is via the computer keyboard. PEBL offers some simple response collection functions that make this easy to do. So, picking up where we

PEBL Programming Tutorial II

2011-11-06T06:00:00.000-05:00

This is Part II of a series of tutorials on PEBL First | Previous | Next In this PEBL Programming tutorial, we will cover the basics of creating a window and displaying text there. As in the previous post, we will use a single Start function. We start by creating a window, and assigning it to a variable we call 'win'. define Start(p){ win <- MakeWindow("black") #You can set the color

PEBL Programming Tutorial I

2011-10-30T21:25:00.001-04:00

This is Part I of a series of tutorials on PEBL First | Previous | Next After an extended blogging break, during which I moved jobs and states, I've planned a series of posts in which I go through some of the basics of programming in PEBL. This will cover some basic programming tutorials I've used during the Cognitive Science tutorial and another course I'm currently teaching. So, to

Two Experimental Psychologists walk into a bar

2011-04-01T06:00:00.005-04:00

It sounds like the start of a bad joke, but in this case, the researchers were Michael Lyvers and Juliette Tobias-Webb. They recently published a paper in Addictive Behaviors in which they escaped the laboratory and conducted an experiment in a local bar using PEBL's version of the Wisconsin Card Sort. I refer to the test as "Berg's Card Sorting Test", after Esta Berg, who originally developed

Inelegant Hacks

2011-03-15T06:00:00.011-04:00

PEBL often has some limits that people run into, and these can sometimes be overcome with other programs. The SystemCall() function gives some powerful means to extend PEBL functionality. All of these examples work for windows, although they could mostly be adapted to OSX or Linux fairly easily. Some of these will make it into the new version of PEBL, either as shown or with a compiled

Announcing: The PEBL Technical Report Series

2011-03-01T06:00:00.001-05:00

The PEBL Technical Reports series is intended to offer an archival location for technical reports, academic term papers and theses, supplemental data, conference presentations, and descriptions/code for new experiments created with the Psychology Experiment Building Language and of use to the PEBL community. The technical report series is intended to give a means for disseminating basic research

Handling Data

2011-02-14T06:00:00.001-05:00

When you start an experiment using a PEBL task, you should give some thought to how you will eventually save and analyze the data. I frequently get requests for help understanding PEBL output after the data were collected, when it is too late for easy elegant fixes and only difficult ugly things are possible. Importantly, especially for the pre-packaged PEBL tasks, there is no guarantee that it

Dragging and drop objects

2011-02-02T21:35:00.001-05:00

Recently someone asked me whether PEBL supports dragging and dropping images around on the screen. I had never really done this before, but it is pretty simple to do. To show how its done, I made a little demo script that works sort of like magnetic poetry. You can download the script to run on your computer here There are probably a lot of card-sorting-type tasks that could use this,

Reimplementing Bem's Feeling the future

2011-01-16T06:00:00.003-05:00

Photo from yd on flickr Daryl Bem has been making headlines with his series of studies that claim to demonstrate ESP and precognition, or in this case, retrocognition. Two of the studies showed that studying words AFTER you recalled them improved how well you did. That is, study a list of words. Then recall as many as you can. Then, half of them are chosen, and you are asked to study them.

Piper's Pursuit Rotor Norm Study

2010-12-19T06:00:00.006-05:00

Figure from Piper (2010) data on PEBL Pursuit Rotor task. Brian Piper from OHSU has just published a norm study on adolescents performing of the PEBL Pursuit Rotor task, called Age, handedness, and sex contribute to fine motor behavior in children. As I've blogged about before, the Pursuit Rotor task has been used in mechanical form for sixty years, and the PEBL version attempts to be

How to make edits to a PEBL Experiment

2010-12-05T06:00:00.004-05:00

One of the most common questions I get is how you make some change to a test in PEBL. This is one of the real advantages of PEBL over many of the canned experiment batteries out there--you have complete control over the tests, and can adapt them to suit your needs if you so chose. Let's start at the very very basics. PEBL experiments are saved in a text file that can be edited with a text editor

Kanizsa shapes

2010-11-21T06:00:00.004-05:00

Screenshot of Kinesza squares generated with PEBL One remarkable visual illusion is the "Kanizsa square", also known as the Pacman illusion. Apparently, it was originally introduced as a triangle, but it might be just as commonly found in its square form today. On the right, you can see it depicted, and it reveals some interesting things about object recognition. There is a strong perceived

Landolt Rings, Landolt Cs

2010-11-07T06:00:00.007-05:00

A "Landolt Ring" or Landolt C has been used as a visual stimulus in a number of contexts. It is especially useful as a visual of visual acuity for subjects who don't know their letters, or in situations where you can't get verbal responses. They are a ring with a gap, and the gap is at a specific angle. Typically this angle is one of the canonical 4 directions. For the latest in my

The Cognitive Decathlon

2010-10-24T06:00:00.001-04:00

A few years back, I worked on a project for DARPA in which we developed a test specification called "The Cognitive Decathlon". It is essentially a version of the Turing Test which was designed to evaluate the capabilities of biologically-inspired artificially intelligent agents. You can read more about it here, here, and here. Sadly (and perhaps inevitably), the program was canceled before we

Interpreting error output

2010-10-10T06:00:00.005-04:00

When you run a PEBL script, the compiler records a bunch of logging messages (mostly at initialization) that can help you understand different initialization problems when they occur. Also, when an error occurs during execution, messages will usually be displayed that can help you figure out the problems. In windows or OSX, these display messages will appear in the terminal screen. On

Buy the book

2010-09-26T06:00:00.004-04:00

I make the PEBL manual dowloadable free of charge, and it is you are welcome to print it out yourself. But it is also available in the handsome perfect-bound paperback via the LuLu print-on-demand press. http://www.lulu.com/product/paperback/the-pebl-manual/12481502 The cost for the bound edition is just $14.99 + shipping, and if you are the type of person who likes to have a manual

Internationalization and Localization

2010-09-12T06:00:00.001-04:00

With the release of PEBL Version 0.11, support for non-English character sets is greatly improved. This includes better handling of non-english accent characters, and also non-western charecters. Fonts First, for many years, I've included the free Bitstream Font series called Vera. This was used, hard-coded, by default in many of the test battery experiments, and in helper functions like

Different ways to run a PEBL experiment

2010-08-29T06:00:00.002-04:00

I'm going to focus on running a PEBL experiment in Windows here, as that is what most users who would need this advice are using. First, most people who use PEBL are aware of the launcher. This is a little front-end that assembles the right command-line arguments. It looks something like this: The launcher defaults to running in the pebl-exp.XX directory, and will be default have some

PEBL on OSX

2010-08-16T17:12:00.004-04:00

PEBL has always been cross-platform, and I designed it using the http://libsdl.org libraries as its first platform, which enables fairly easily compiling for Windows, Linux, OSX, and probably with some efforts things like Android and iPhone/iPad. Several versions ago, I stopped distributing a version for OSX because I didn't have a Mac anymore. But we recently acquired one, and so the OSX

Attneave shapes

2010-08-15T08:00:00.045-04:00

Fred Attneave and Malcolm Arnoult did some classic studies in the 1950s which used 'nonsense shapes' as stimuli. The term 'nonsense shape' is sort of a silly term, and says a lot about the research of the day, where in order to gain scientific rigor, researchers attempted to get rid of all the idiosyncratic associations between psychological stimuli and an Ss experience (even referring to a "

The PEBL Trail-making test: Results

2010-08-01T08:00:00.002-04:00

A while back, I blogged about the trailmaking test, and some of the algorithms used to do target path layout to hopefully produce better and more consistent results. The test actually contains two conditions: 1. Moving through points 1..25; and 2. Alternating between letters and numbers: 1 A 2 B 3 C .... I ran fifteen rounds of the test on myself. Each point configuration is tested twice: once

PEBL Story on the Sourceforge Blog

2010-07-27T10:09:00.000-04:00

The sourceforge blog has featured PEBL in one of its recent posts. Read more at: http://sourceforge.net/blog/a-pebl-in-the-neuroscience-sea/

PEBL 0.11 Released

2010-07-24T14:55:00.003-04:00

I've released PEBL Version 0.11 and version 0.6 of the PEBL Test battery Version 0.11 contains a lot of under-the-hood fixes to memory management. Previously, PEBL had a number of memory leaks which could end up crashing the system if it ran for too long. Most (all?) are now gone, which should improve performance. Also, a new widget called a 'canvas' is available, which lets you create more

Corsi Block-Tapping Test

2010-07-18T08:00:00.008-04:00

The Corsi Block-Tapping test, sometimes referred to as "Corsi Blocks", is a classic test used as a visuo-spatial version of digit span. Instead of hearing digits, you see blocks attached to a board, and the experimenter points at a sequence of blocks which must be reproduced by the subject. Blocks are used because it allows them to be numbered on their back, hidden from the subject but visible

Gabor Patch

2010-07-04T08:00:00.007-04:00

With the upcoming release of PEBL 0.11, I have implemented a canvas, which allows you to draw on it and set arbitrary pixels, as well as composite objects together. This moves PEBL toward greater capability in a number of visual perception domains, where noisy masks are created or sinusoidal gratings are used. One of the most famous of these types of stimuli is known as the 'Gabor patch': a

Visual Search

2010-06-20T08:00:00.014-04:00

Visual search tasks have a long tradition in understanding the cognitive psychology of vision. Comparing different search conditions reveals some fundamental aspects about our visual system. Anne Treisman is usually given much of the credit for popularizing the tasks, and folks like John Palmer, Jeremy Wolfe and Laurent Itti have developed reactions to/implementations of these ideas in

The Item-order test

2010-06-06T06:00:00.002-04:00

Researchers have been interested in dissociating item and order information in short-term memory since at least Bill Estes and Alice Healy in the early 1970s. A test exists in the Unified Tri-Services Cognitive Performance Assessment Battery (UTCPAB; see Perez, Masline, Ramsey, and Urban, 1987) that explicitly tests item and order information, but in the context of a same-different test. Now

Design and randomization II: the ShuffleCondition function

2010-05-23T08:00:00.003-04:00

A while back, someone emailed me about a particular randomization scheme they wanted. > i am wondering whether it is possible to pseudo-randomize lists, i.e., > to produce "random" sequences with constraints such as that each element > cannot appear more than three times in a row etc. > > i am going to need this in training a discrimination between two > stimuli. the stimuli should appear to the

The Stroop Test

2010-05-09T08:00:00.002-04:00

The Stroop Test is a classic phenomena showing the importance of attentional filtering and interference. I wanted to implement a version in PEBL for the PEBL Test battery. The basic setup is this: It is easy to name colors. It is easy to read colors. But what about naming the color or reading the name of colored words (when they are inconsistent). One would expect these to be harder, but are

The Pursuit Rotor Task

2010-04-24T23:18:00.003-04:00

Recently I had a brief foray into into research on manual dexterity (award-winning BRiMS paper can be downloaded here), and I ran into the Pursuit Rotor task. Originally, the task had a person hold a stylus in one hand and try to follow a disc moving quickly on a turntable. When they were 'on' the disc, a circuit was completed and a timer activated. A measure of dexterity was the proportion of

Testing Fitts's Law

2010-04-11T08:00:00.004-04:00

Paul Fitts was a researcher in psychology who studied skilled performance. One of his most notorious (and misinterpreted) discoveries was named "Fitts's Law" or sometimes "Fitts' Law" or "Fitts Law" or even "Fitt's Law", and it concerns how long it takes to make aimed movements. The finding shows that the time to make prepared aimed movements is a tradeoff between the target size and the

Design and Randomization I

2010-03-21T08:00:00.003-04:00

Proper randomization is critical for the causal inference that experiments provide. This is true across subjects, but also within a subject, in the way he or she is exposed to a set of trials or conditions. Many standard programming languages permit randomization, sampling, and design to be performed, but do not make it easy. In PEBL, I strive to provide flexible functions that make standard

I've been DMCA'ed--Updated

2010-03-16T20:00:00.007-04:00

The screencast of the running PEBL Trails experiment in the last blog post received a DMCA notice on YouTube. The complainant was SpecialtyAutomated. SpecialtyAutomated is also the name of a company that sells a number of different cognitive tests, including an online Trail-making test. I have no way of knowing whether the complainant was a representative of that company. UPDATE: After I

The "Trail-Making" test and 2D layout

2010-03-14T08:00:00.003-04:00

A while back I put together a version of the "Trail-making" test. This is a test that is apparently used for detecting different kinds of brain injury, but has also traditionally been used as a test of eye-hand coordination and probably procedural skill. The most common version is by Reitan, as part of the Halstad-Reitan Battery, but it apparently goes back at least 60 years to tests like the

Using the PEBL Survey Generator

2010-03-06T20:00:00.000-05:00

Version 0.10 of PEBL offers a survey generator, distributed in the Test Battery. It is designed to offer only limited interaction, so that the respondent sees only the survey questions and keys must make responses to continue. And as an experimenter, you can design it simply by editing a .csv file in your favorite spreadsheet or text editor. There are a lot of web-based options for creating

Intellectual Property and Norms in PEBL

2010-02-28T14:10:00.000-05:00

One of the most frequent questions that comes up is about whether PEBL violates intellectual property of others 'standard' tests. There are really four closely-related issues here, which I wanted to lay out here. They include (1) copyright (2) trademark (3) patents and (4) norm relevancy. Copyright Copyright covers things like written material, artwork, source code, possibly instructions,

Tower of London

2010-02-21T08:00:00.003-05:00

The Tower of London test (TOL) is a cognitive planning test akin to the Tower of Hanoi (TOH), initially developed by Tim Shallice (see Shallice, T. (1982). Specific impairments of planning. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 199-209.) Unlike the TOH, it requires relatively less deep thinking, recursion, impasses, and so on, but it can

Inaugural PEBL Blog Post

2010-02-14T21:24:00.001-05:00

In an effort to promote the use of PEBL as a research and testing tool, I've committed myself to creating this blog about various aspect of PEBL (the Psychology Experiment Building Language) and the PEBL Test Battery. My intent is to update roughly every two weeks for about six months, and after that I'll see. Look for updates every other Sunday for about six months, and then maybe a slightly