Attention and Vision Study

What are we studying?

Most humans are highly dependent on vision when we interact with the world. Vision feels like an effortless process -- we just open our eyes and immediately "see" everything around us. In reality, there is so much information entering our visual system at any given moment that we cannot possibly process or perceive it all at one time without overwhelming our visual system.

Fortunately, not all of the visual information around us is relevant at any given moment. If you are crossing a road, for example, it is essential that you see the cars, but it's not very important that you see the surrounding trees, birds, or buildings. So, your visual system needs a way of selecting just the relevant visual information for processing while ignoring or filtering out the irrelevant information. The mechanism that does this is what we call attention.

Although much is known about attention and how it operates, there is still much more to be learned. In this study, we are interested in learning about how individuals are able to pay attention to a large or a small region of space. Imagine, for example, scanning the shelves of a flower stall to generally see what kinds of bouquets they have. This would require fairly broad attention (see the left-hand image below). Once you see a bouquet you like, and you would like to check what it costs, you need to narrow your attention to just the price tag (right-hand image below). We are interested in learning a) how quickly people can change the size of the area they pay attention, b) whether some people can do that more effectively than others, and c) how paying attention broadly or narrowly affects visual processing.

Figure 1. In the attentional spotlight metaphor, information that falls within the spotlight (the area that can be seen clearly and in full colour in the image to the left) is attended while information that falls outside the spotlight is not. The location and size of the spotlight can be adjusted so that the most relevant information in a scene can be processed. Panel A of the image illustrates a broad attentional spotlight which allows many bouquets to be processed at one time. In order to view the price of a single bouquet, the attentional spotlight must be narrowed in on just that small portion of the visual field, as illustrated in Panel B.

What research methodology was used?

We know from research by Castiello and Umilta (1990) that the attentional spotlight automatically changes size to match the size of a shape that appears suddenly. In this study, we used suddenly-appearing squares of different sizes (small or large) to trigger your attentional spotlight to automatically change size.

The Independent Variable was the size of the square (small or large), which caused your attentional spotlight to become small or large.

The Dependent Variables were (a) how quickly (reaction times in milliseconds) your responded to a target, and (b) how accurately you responded to a target.

What did we find?

There is existing research that shows some of the ways in which the size of the spotlight changes visual processing, but we were able to learn quite a lot of new information. As just one example, in this trimester's research we showed that changing the size of the spotlight affects how quickly you can detect the disappearance (offset) of an object. We also found that people who were better able to change the size of their spotlight were the most efficient at detecting the offset of a stimulus. Why might this matter? Keep reading!

Why does this matter?

Consider what happens when you see a traffic light change from green to red (technically, of course, it goes green to orange to red, but the idea is the same!). The green light disappears (offsets) and then the red light appears (onsets). If you can detect more quickly that the green light has disappeared, this will give you additional time to plan your stop and to actually hit the brakes in time, making you a safer driver. It turns out that the size of your attentional spotlight affects how quickly you can do this. The size of your attentional spotlight changes depending on factors such as where you are paying attention and your mood.

Curious to learn more about attention or visual cognition? Here are some books that you might enjoy:

• Chabris, C. F., & Simons, D. J. (2010). The invisible gorilla: And other ways our intuitions deceive us. Harmony.

• Doidge, N. (2007). The brain that changes itself: Stories of personal triumph from the frontiers of brain science. Penguin. (Available as an e-book in the City of Gold Coast public library via Overdrive)

• Kahneman, D. (2011). Thinking, fast and slow. Macmillan. (Available as an e-book in the City of Gold Coast public library via Overdrive)

• Gladwell, M. (2006). Blink: The power of thinking without thinking. (Available as an e-book in the City of Gold Coast public library via Overdrive)