Take a look at this short video clip (QuickTime required). It's called an RSVP (rapid serial visual presentation), meaning that it's a quick sequence of still images. In this case, it's a random sequence of letters. Your job is to look for a number among the letters. At some point during the clip, you should also see a dot flash in one corner of the video. You also need to take note of the corner in which the dot appears. A rectangle will flash shortly before the dot, possibly giving a clue to where the dot will appear:
It's actually not a very difficult task (especially when I tell you that there weren't any numbers in the clip). Is this one more difficult?
Now the rectangle is acting as a distractor instead of a cue for where the dot appears. But still, it's not a very hard task.
Some researchers have speculated that spotting something that suddenly appears outside of your area of focus is automatic, meaning that other cognitive processes don't interfere with it. It would certainly be handy if that was the case -- that way we can pay attention to what we're cooking on the campfire, but still be ready to respond if, say, a bear suddenly strikes.
If we're not distracted with a second task, such as looking for numbers in a stream of letters, then having some sort of cue to indicate where to look for an item should help us identify it quicker. If this process is automatic, then the cue should speed the identification even while we're distracted with another task.
A team led by Valerio Santangelo showed Oxford students displays like this, mixing them with real number-identification tasks so they had to focus on both problems. Some of the time, the students were told to ignore the numbers and only attempt to identify the location of the dot as quickly as possible. Some of the time, they simply focused on a crosshair at the center of the screen and again identified the location of the dot as quickly as possible after it appeared. As you might expect, when the rectangular cue appeared on the same side as the dot, overall the responses were faster. But when responses were broken down by the different tasks viewers had performed, a different pattern emerged:
The entire difference between cued and uncued responses was accounted for by the crosshairs task, when viewers needed only identify the location of the dot. When viewers were distracted by the number identification task, or even when they were only focusing on the letters and not required to search for numbers, there was no difference between the cued and uncued response times. In fact, the difference between the numbers and letters task and the letters only task was not significant.
In a separate experiment, the procedure was repeated with one key difference: instead of visually searching for a dot, they had to identify where a sound was coming from. Three speakers in a column on each side of the computer monitor played the sounds, with the cue coming from the center speaker, and the sound listeners had to identify coming from one of the four corners. The results were practically identical.
Finally, the researchers repeated both experiments using an RSAP (rapid sequential audio presentation) instead of an RSVP: Instead of playing a video with pictures of the letters, listeners focused on a crosshair in the center of the screen while listening to a recording of a person rapidly speaking letters. Again, the respondents were searching either for a dot appearing on the screen or a sound coming from one of four speakers. Once again, the results followed the identical pattern of the first experiment.
So regardless of whether the item viewers/listeners need to locate is a sound or an image, and regardless of whether they're being distracted by images or sounds, cues don't help them locate the item in question. Cues only help when there are no distractions.
The researchers argue that this demonstrates that responding to items outside the area of focus is not an automatic process. When the mind is occupied with other functions, responses to cues are slowed significantly.
Santangelo, V., Olivetti Belardinelli, M., Spence, C. (2007). The Suppression of Reflexive Visual and Auditory Orienting When Attention Is Otherwise Engaged.. Journal of Experimental Psychology: Human Perception and Performance, 33(1), 137-148. DOI: 10.1037/0096-1523.33.1.137
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The study says that almost everyone notices the dot, though right? just that it's slowed if we're using the particular faculty for something else?
I would have made the hypothesis myself, really. apparently our eyes do capture mostly everything in their field of vision, the bottleneck is in our brains. The brain goes "wtf, a dot?" and how long it takes us to recognize that, and verbalize it (or however they were doing it) is the latency.
For the record, i "saw" the second dot a LOT faster than the first dot. the first dot was a blur (the rectangle and dot sorta merged on my screen).
That's a nice little study. The following is a general comment about the statistical graphics (I have become a regular reader over the last few weeks).
Some days ago there were several readers telling you that they used Cognitive Daily in class, which seems a really good idea, because your posts are not only usually very interesting, but also accessible without being oversimplifying (cheers for that!). I just have two suggestions concerning statistical graphics that might even improve the quality of the posts when intended for teaching:
Anyways, I really like your blog, and probably will try to include in my classes either in some way. Cheers
For the record, i "saw" the second dot a LOT faster than the first dot. the first dot was a blur (the rectangle and dot sorta merged on my screen).