﻿<?xml version="1.0" encoding="UTF-8"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/"><channel><title>Millisecond Forums » Millisecond Forums » Inquisit 4  » Negative Stimulus Onset Times</title><generator>InstantForum 2017-1 Final</generator><description>Millisecond Forums</description><link>https://forums.millisecond.com/</link><webMaster>Millisecond Forums</webMaster><lastBuildDate>Tue, 28 Jul 2026 01:26:32 GMT</lastBuildDate><ttl>20</ttl><item><title>Negative Stimulus Onset Times</title><link>https://forums.millisecond.com/Topic27567.aspx</link><description>Hello,&lt;br/&gt;&lt;br/&gt;I'm new to using Inquisit and have been going through the tutorials while writing my own code. &amp;nbsp;I've been puzzled that in both my code and in the tutorials, I am getting negative numbers in the data file under stimulusonset. &amp;nbsp;I've attached a data file from the CovertAttention tutorial. I'd like to verify the accuracy of the timing of my system. Does the negative mean that the stimulus is appearing prior to when the trial was expected to start?&lt;br/&gt;&lt;br/&gt;Thanks for your help in advance!&lt;br/&gt;&lt;br/&gt;Best,&lt;br/&gt;Anthony</description><pubDate>Wed, 07 Aug 2019 12:22:04 GMT</pubDate><dc:creator>asali</dc:creator></item><item><title>RE: Negative Stimulus Onset Times</title><link>https://forums.millisecond.com/Topic27569.aspx</link><description>&lt;div data-id="27567" class="if-quote-wrapper" unselectable="on" data-guid="1565205521671"&gt;&lt;a class="quote-para" unselectable="on" style="display: none;" href="#" data-id="27567" title="Move Cursor Below" contenteditable="false"&gt;&lt;span unselectable="on"&gt;+&lt;/span&gt;&lt;/a&gt;&lt;a class="quote-delete" unselectable="on" style="display: none;" href="#" data-id="27567" title="Delete Quote" contenteditable="false"&gt;&lt;span unselectable="on"&gt;x&lt;/span&gt;&lt;/a&gt;&lt;span unselectable="on" class="quote-markup"&gt;[quote]&lt;/span&gt;&lt;div unselectable="on" class="if-quote-header" contenteditable="false"&gt;&lt;div unselectable="on" class="if-quote-toggle-wrapper"&gt;&lt;a class="if-quote-toggle quote-link" href="#" data-id="27567" title=" "&gt;&lt;/a&gt;&lt;/div&gt;&lt;span unselectable="on" class="quote-markup"&gt;[b]&lt;/span&gt;asali - 8/7/2019&lt;span unselectable="on" class="quote-markup"&gt;[/b]&lt;/span&gt;&lt;/div&gt;&lt;div class="if-quote-message if-quote-message-27567"&gt;&lt;div class="if-quote-message-margin"&gt;Hello,&lt;br/&gt;&lt;br/&gt;I'm new to using Inquisit and have been going through the tutorials while writing my own code. &amp;nbsp;I've been puzzled that in both my code and in the tutorials, I am getting negative numbers in the data file under stimulusonset. &amp;nbsp;I've attached a data file from the CovertAttention tutorial. I'd like to verify the accuracy of the timing of my system. Does the negative mean that the stimulus is appearing prior to when the trial was expected to start?&lt;br/&gt;&lt;br/&gt;Thanks for your help in advance!&lt;br/&gt;&lt;br/&gt;Best,&lt;br/&gt;Anthony&lt;a class="if-quote-goto quote-link" href="#" data-id="27567"&gt;&lt;span class="goto"&gt;&lt;/span&gt;&lt;/a&gt;&lt;/div&gt;&lt;/div&gt;&lt;span class="quote-markup"&gt;[/quote]&lt;/span&gt;&lt;/div&gt;&lt;br/&gt;A negative onset would usually indicate some issue with respect to syncing to the system's graphics card / display refresh rate. The timings in the file appear internally consistent, but there may be some off-by-one frame issue. Try updating your graphics card driver and make sure there is no other application running in the background that might interfere with the display system while Inquisit is running.&lt;br/&gt;</description><pubDate>Wed, 07 Aug 2019 12:22:04 GMT</pubDate><dc:creator>Dave</dc:creator></item></channel></rss>