Abstract
One way to estimate how long it takes to process visual information is by measuring reaction times. How much longer it takes to respond to a certain aspect of a visual stimulus than to respond to a similar stimulus when the aspect in question does not need to be processed can give you an indication of how long it takes to do the processing. Reaction times are easily measured by asking people to press or release a button. However, responses can differ in vigor as well as in latency. We suspected that the latencies of less vigorous responses might be overestimated when relying on buttons to determine the reaction time. To examine whether this is true, participants were asked to lift their finger off a button as soon as they heard a tone. We compared two conditions. In one condition there was a straw balancing across two blocks just above the button. Participants were told not to knock the straw off the blocks. In the other condition there was no straw. Otherwise the conditions were identical. When we used the moment at which the finger released the button as the reaction time, we found that the reaction time was significantly longer in the presence of the straw. Since our button was actually a force sensor, we could also determine the moment at which the force started to change. When reaction time was measured in this manner, the straw did not influence the judged latency. Thus, the way in which the reaction time is measured can influence the conclusion that we draw from the data. As properties of a stimulus can influence the magnitude of the response as well as its latency, it is important to be aware that the magnitude of the response might influence the estimated latency.
Meeting abstract presented at VSS 2016