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# Chelsea

### Emory University

Active since 2014

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Question

How to ensure equal probability of stim appearing on L or R of screen without hard-coding? Description inside.
Hi, I am working on a task in Psychtoolbox where I'd like to display a stimulus 50% of the time on the left side of the scree...

7 years ago | 1 answer | 0

### 1

Question

Trim a dataset based on array of subject IDs that correspond to rows to keep in matrix
Hi, I have a large matrix, where the first column is subject IDs (around 2000 people). For a particular analysis, I'd only l...

7 years ago | 1 answer | 0

### 1

Question

How to loop through matrices, pull the nth row of each, and append to new matrix?
Hello, I am trying to create a for loop that will go through a list of matrices, pull the nth row (e.g., 3rd) from each, and...

8 years ago | 0 answers | 0

### 0

Question

If I have a 2100 x 16 matrix, how can I specify for a certain value to go in to rows 1:84, then another into 85:169, and repeat this 25 times in some kind of loop?
Hi, Sorry for the random question. I'm trying to simulate data to follow a certain format of output file. I already have a s...

8 years ago | 1 answer | 0

### 1

Question

Using for loop to output modified tables - how can I loop through names of tables I'm calling to be modified?
Hi, I'm using a for loop to take a list of tables (x001, x002, x003, etc.), and then modify each one to include only certain...

8 years ago | 1 answer | 0

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Question

Capture reaction time - code not working
Hi, I'm trying to capture simple reaction time, but the code I have isn't working (i.e., gives me RT of 0.00000008, etc.). ...

8 years ago | 0 answers | 0

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Question

Merge tables with different dimensions?
Hi, I'm trying to use vertcat to add together a sequence of tables. The problem is, some are 24x22, some are 24x19, etc. ...

8 years ago | 3 answers | 0

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Question

Is it possible to rename columns in a table?
Hi, I'm hoping there's a simple way to rename columns in a table. I don't need anything complicated, I'd just like to rename, fo...

8 years ago | 7 answers | 5

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Question

Generate new file w/ each iteration of for loop. Problem of same output in each new file?
Hi, I'm trying to design a for loop that takes 100 random rows from a sample data set, and saves that into a new output file...

8 years ago | 1 answer | 0

### 1

Question

KbWait() - Wait for response for x # seconds or time out?
Hi, I'm trying to create code where I wait for a user's key response for 5 seconds. If there's no response in 5 seconds, the...

8 years ago | 0 answers | 0

### 0

Question

Trying to change name of image file in for loop - use %s?
Hi, I'm trying to create a for loop, where I gather screen shots and save them (trial 1, trial 2..., etc.). I tried to use t...

8 years ago | 2 answers | 1

### 2

Question

How can I set KbWait to wait 5 seconds for an input, and if none, move on in Psychtoolbox?
Hi, I'm trying to use KbWait in an experiment. The subject must make a key press within 5 seconds, or the experiment will mo...

8 years ago | 0 answers | 0

### 0

Question

How can I make sound randomly occur during 10 second presentation of other stimulus?
Hi there, I'm using Psychtoolbox to create an experiment. I have the code for sound, presentation of images, etc. I'm trying...

8 years ago | 2 answers | 0

### 2

Question

Determine and present result based on set probabilities?
Hi, I'm making a simple experiment where a person gains or loses several dollars based on what item on the screen they choos...

8 years ago | 0 answers | 0

### 0

Question

How do I get two images to display top and bottom of screen in Matlab/Psychtoolbox? I can already do left and right sides.
Hi, I'm trying to display two images, one on the top, and one at the bottom of the screen in Psychtoolbox. I know how to do that...

8 years ago | 1 answer | 1

### 1

Question

Display numerical output with sprintf?
Hi, I am creating a Psychtoolbox script where a subject completes button presses. The number of button presses he or she com...

8 years ago | 1 answer | 0

### 1

Question

How can I get one image-of a pair-to display depending on condition chosen?
Hi. I'm trying to create a task using Psychtoolbox. Basically, I'll have two images displayed, under them will be two questions/...

8 years ago | 0 answers | 0

### 0

Question

Collect data from button response
Hi, I'm trying to collect keyboard input, to save to a file (either "s" or "l" key...). Here is the code I have now. I had previ...

8 years ago | 1 answer | 0

### 1

Question

How can I play a sound for last second of displaying an image?
Hi, I have a for loop that displays pairs of images. For some of the image pairs, I want to play a one second white noise cl...

8 years ago | 0 answers | 0

### 0

Question

How can I control the timing of playing a sound?
Hi, I'm trying to play a sound (clip is 10 seconds) for 5 seconds. How can I stop the sound after 5 seconds? I also want to ...

8 years ago | 1 answer | 0

### 1

Question

How do I find array elements that meet some condition with strcmp?
Hi, I have a vector of image files. I would like to pull out only a subset of these files which meet a certain condition. Th...

8 years ago | 1 answer | 0

### 1

Question

How can I display two images at once?
Hi, I can't seem to figure out how to display two images at the same time. I've read about subplots, figures, etc., but I ju...

8 years ago | 2 answers | 2

### 2

Question

Assign output a name?
Hi, I am working on something where I have a vector of image files, and I get Matlab to shuffle them and give me one. I woul...

8 years ago | 1 answer | 0

### 1

Question

How can I pull a random image to display, from a folder of images using Psychtoolbox?
Hello, I am trying to show an image, randomly selected from a folder of images. I'm using Psychtoolbox. How do I instruct it...

8 years ago | 2 answers | 0