What is selective attention?

What is selective attention?

Attention is a cognitive process, or brain function that has as its main objective to allocate the cognitive processing towards a stimulus, let it be visual, auditory or related to some other sense. That is, attention defines which information is most relevant among the various sensory inputs that occur at the same time as the stimulus.

Thus, attention is the ability to keep the mental processes focused on something that we are observing or hearing, for example. With regard to the time we can remain in attentional state, we can maintain this state for a momentary period (imagine that you are driving and the vehicle next to you suddenly sounds the horn to avoid an accident, the moment when only the horn sounds, the cognitive preference is defined as momentary attention) or for a sustained period of time (when we spend hours playing video games or writing an article, for example).

Although attention is a complex cognitive process that demands the orderly structuring of several brain areas aimed at understanding and maintaining this processing for a certain period, it is also an important phylogenetic process for species evolution, reproduction, and food production. The most basic process of reallocating neural (ie, attentional) processing is observed in a fight or flight reaction, for example. When we are faced with a menacing event, the vast majority of our mental faculties are directed to such stimuli (Figure 1) in order to perform a fight or flight action. The fight or flight reaction is observed in the great majority of organisms, whether "rational" or not, we can infer that attention is present phylogenetically in various organisms and that this process is not exclusively of "rational" or human organisms.

Figure 1 - Illustration of a fight or flight situation.

In this sense, the vast majority of daily activities can be mediated by attentional processes. To better understand how this occurs, we need to explain the main types of attention. For this, we can define four types of attention, which are: sustained, selective, alternated and divided.

• Sustained Attention: Occurs when we have the ability to focus and direct much of our cognitive processing to an ongoing task over a long period of time without being distracted [1, 2]. It is one of the primary elements of attentional processes, it is in this type that we are able to perform tasks for long periods of time.

• Selective attention: Attentional subtype in which we are able to select, from various factors and characteristics of a stimulus and focus on only one factor of interest. This process occurs concomitantly with the filtering of non-focused parts of the stimulus (Figure 2). In other words, selective attention allows us to select the stimulus that we want to pay attention to.

• Alternate attention: Ability to change the focus of attention between different tasks or parts of the stimulus. In this kind of attention, we need different cognitive demands, such as decision making, for example.

• Attention divided: Capacity in which we are able to process two or more characteristics of the stimulus at the same time. Lately, it has also come to be known as multitasking ability.

Figure 2 - Illustration of a possible visual scene with the different possible focus of attention(in yellow). The role of selective attention here is to focus on only one possible object, automatically ignoring others.

In this sense, the investigation about the mechanisms and cerebral pathways responsible for the four main attentional subtypes began several decades ago. Initially, the studies were mostly empirical, where the researchers discussed the results based on, and through oral and written responses of the research participants [3]. However, with the advancement of neuroscience and neuroimaging and response time techniques, research on the mechanisms for each attentional type has taken a different course. This led to the description of the brain areas that theoretically coordinate the processing of attention.

As was initially hypothesized, studies indicate that some areas of the parietal cortex are involved in the attentional processes [4-7]. The parietal cortex is a region of the cortex well known as an associative area, mainly to control the senses. Quantitative methods have already measured the role of this area in the physiology of attentional mechanisms, such as Event-related Potential (ERP). One of the ERP's that appear to be a biomarker for attention is the P300, as described in previous studies [8-11].

With the emphasis on selective attention, which seems to be one of the main types of amplifiers of synchronization or recruitment of the areas related to this attentional subtype. A classic study that measures reaction time for selective attention is the Dichotic Listening Task experiment. In this experiment, a headset is placed on the ear´s participant, followed by the protocol instructions. The participant will hear two different phrases, one in each ear, and will repeat orally the phrase indicated by the researcher (Figure 3) [12,13]. This is a classic selective attention experiment that has been used for at least seven decades.

Figure 3 - Schema demonstrating the dichotic listening task experiment.

Other evidence showing the role of selective attention in signal amplification for the stimulus chosen by the focus of attention is illustrated in the video below. In the video, a cap with EEG electrodes is placed on the participant's head that goes through an experiment session similar to that proposed by the dichotic listening task. The participant hears two voices coming from two different speakers, and when he focuses on one voice, there was an attenuation in the un-selected voice and an amplification in the voice he chose to focus on. The direction of the voice was instructed by the experimenter indicating the selection with a stick on the side.

Although selective attention is able to direct and amplify the stimulus in focus, the other stimuli that are being attenuated are not stopped being processed. Using the dichotic listening task, Treisman (1964) demonstrated that the participants were able to discriminate and identify the attenuated message (or voice). He proposed a model for selective attention regarding amplification and attenuation of the stimuli in focus (Figure 4).

 



Figure 4 - Selective attention Model related to actuation. The beep of the two ears is processed and the selective attention attenuates the stimulus that is not in focus as well as amplifies the focused stimulus.

References

[1] - Pardo, J. V., Fox, P. T., & Raichle, M. E. (1991). Localization of a human system for sustained attention by positron emission tomography. Nature, 349(6304), 61.

[2] - Lahey, B. B., Pelham, W. E., Schaughency, E. A., Atkins, M. S., Murphy, H. A., Hynd, G., ... & Lorys-Vernon, A. (1988). Dimensions and types of attention deficit disorder. Journal of the American Academy of Child & Adolescent Psychiatry, 27(3), 330-335.

[3] - Duncan, J. (1984). Selective attention and the organization of visual information. Journal of Experimental Psychology: General, 113(4), 501.

[4] - Lamb, M. R., Robertson, L. C., & Knight, R. T. (1989). Attention and interference in the processing of global and local information: Effects of unilateral temporal-parietal junction lesions. Neuropsychologia, 27(4), 471-483.

[5] - Coull, J. T., Frith, C. D., Frackowiak, R. S. J., & Grasby, P. M. (1996). A fronto-parietal network for rapid visual information processing: a PET study of sustained attention and working memory. Neuropsychologia, 34(11), 1085-1095.

[6] - Chambers, C. D., Payne, J. M., Stokes, M. G., & Mattingley, J. B. (2004). Fast and slow parietal pathways mediate spatial attention. Nature neuroscience, 7(3), 217.

[7] - Ansari, D., Lyons, I. M., van Eimeren, L., & Xu, F. (2007). Linking visual attention and number processing in the brain: The role of the temporo-parietal junction in small and large symbolic and nonsymbolic number comparison. Journal of Cognitive Neuroscience, 19(11), 1845-1853.

[8] - Spencer, K. M., & Polich, J. (1999). Poststimulus EEG spectral analysis and P300: attention, task, and probability. Psychophysiology, 36(2), 220-232.

[9] - Gray, H. M., Ambady, N., Lowenthal, W. T., & Deldin, P. (2004). P300 as an index of attention to self-relevant stimuli. Journal of experimental social psychology, 40(2), 216-224.

[10] - Polich, J. (1986). Attention, probability, and task demands as determinants of P300 latency from auditory stimuli. Electroencephalography and clinical neurophysiology, 63(3), 251-259.

[11] - Brandeis, D., Banaschewski, T., Baving, L., Georgiewa, P., Blanz, B., Schmidt, M. H., ... & Scheuerpflug, P. (2002). Multicenter P300 brain mapping of impaired attention to cues in hyperkinetic children. Journal of the American Academy of Child & Adolescent Psychiatry, 41(8), 990-998.

[12] - Geffner, D. S., & Hochberg, I. (1971). Ear laterality performance of children from low and middle socioeconomic levels on a verbal dichotic listening task. Cortex, 7(2), 193-203.

[13] - Jäncke, L., Specht, K., Shah, J. N., & Hugdahl, K. (2003). Focused attention in a simple dichotic listening task: an fMRI experiment. Cognitive Brain Research, 16(2), 257-266.