Mapping the Centre-Surround Attentional Field

Researchers: Kyle S. Zeilinga, Dr. Lisa Jefferies

Consider for a moment: What happens when you open your eyes? You are presented with a barrage of visual information. A video camera would record all this information. You, however, can pay attention to a given object in your visual field. By focusing your attention on that object, you can enhance processing in that area of your visual field (Posner & Cohen, 1984; von Helmholtz, 1924). For example, attention can improve spatial resolution (Carrasco et al., 1995); like upgrading from 1080p “Full HD” to 4K “Ultra HD”. More than this, there is evidence that you can inhibit visual processing around your attentional focus (e.g., Cutzu & Tsotsos, 2003). The combination of this enhancement and inhibition is called the centre-surround attentional field (see Figure 1).

Figure 1. The Centre-Surround Attentional Field

Our Research Questions

We know that some factors moderate the strength of attentional enhancement, but we don’t know how they affect attentional inhibition. Firstly, we know that attentional enhancement is stronger when the attentional field is narrow than when it is broad (Castiello & Umiltà, 1990). Therefore, in Experiment 1 we tested whether a narrow attentional field would result in stronger attentional inhibition than a broad attentional field. Secondly, we know that attentional enhancement is stronger when a difficult task is presented within the attentional field than when an easy task is presented (Lavie et al., 2004). Therefore, in Experiment 2 we tested whether a more difficult task would result in stronger attentional inhibition than an easy task.

How Did We Test the Research Questions?

Experiment 1

We presented either a large or a small square to cue a broad or narrow attentional field respectively. The size of the square was the independent variable. Then, we presented a small circle (a target) and asked participants to press a key as quickly as possible when they saw the target. The dependent variable was the reaction time (in milliseconds) to the target. We systematically varied the location of the target (how far away from the central plus sign) target to measure the allocation of attention around the visual field in response to the cue. See Figure 2 for an animated depiction of the paradigm.

Figure 2. Paradigm for Experiment 1

Experiment 2

We presented a square with a gap that could appear either on the left or right side. The task was to discriminate which side the gap appeared on. The difficulty of the task was manipulated by making the gap either very small or quite large. Task difficulty was the independent variable. We then measured the allocation of attention around the visual field in the same way as in Experiment 1. See Figure 3 for an animated illustration of the paradigm.

Figure 3. Paradigm for Experiment 2

What Did We Find?

In both experiments, we found evidence of attentional enhancement. However, we found no evidence of attentional inhibition in either experiment. So, neither hypothesis was supported; this is the fun of science – new ideas! It tells us that surround inhibition is not an integral component of attention – sometimes, enhancement alone is sufficient. It seems that there are conditions that need to be met for surround inhibition to arise. As it stands, we don’t really know what those conditions are. Although, we can contrast this study with studies that found attentional inhibition to gleam insight into what those conditions may be.

Future Directions

The most important difference between this study and studies that have found attentional inhibition is that they often use distractor stimuli. So, distracting stimuli may be necessary for surround inhibition to occur. Applied, this would hypothetically mean that surround inhibition could arise when you are looking for a friend in a bustling marketplace crowd; but not when you are looking at a ship anchored in a calm bay. Future researchers may investigate whether distracting stimuli are necessary for surround inhibition and help contribute to our theoretical understanding of how the visual attention system works.

References

Carrasco, M., Evert, D. L., Chang, I., & Katz, S. M. (1995). The eccentricity effect: Target eccentricity affects performance on conjunction searches. Perception & Psychophysics, 57(8), 1241–1261. https://doi.org/10.3758/BF03208380

Castiello, U., & Umiltà, C. (1990). Size of the attentional focus and efficiency of processing. Acta Psychologica, 73(3), 195-209. https://doi.org/https://doi.org/10.1016/0001-6918(90)90022-8

Cutzu, F., & Tsotsos, J. K. (2003). The selective tuning model of attention: psychophysical evidence for a suppressive annulus around an attended item. Vision Research, 43(2), 205-219. https://doi.org/https://doi.org/10.1016/S0042-6989(02)00491-1

Lavie, N., Hirst, A., De Fockert, J. W., & Viding, E. (2004). Load theory of selective attention and cognitive control. Journal of Experimental Psychology, 133(3), 339. https://doi.org/10.1037/0096-3445.133.3.339

Posner, M. I., & Cohen, Y. (1984). Components of visual orienting. In H. Bouma & D. G. Bouwhuis (Eds.), Attention and performance X: Control of language processes (Vol. 32, pp. 531-556). Erlbaum.

von Helmholtz, H. (1924). Treatise on physiological optics (J.P.C. Southall, Trans.; 3rd ed.). Optical Society of America. https://doi.org/10.1037/13536-000