Memory and attention

Introduction

In the environment, we are constantly bombarded with a great range of stimuli. Most of these stimuli are of no relevance to us and we have the ability to successfully filter out most of them. This ability to filter out certain stimuli is referred to as selective attention. Part of my research concerns how some stimuli still breaks through the filter and capture our attention. In this line of work there has been shown individual differences in the ability to successfully filter out irrelevant information. For instance, people with greater working memory capacity has shown to be less distracted by auditory distractors (i.e., one’s own name) than individuals with low working memory capacity (e.g., Conway, Cowan & Bunting, 2001. In this post I will focus on the Working Memory (WM) and its interaction with attention. The basis of this discussion will be chosen parts of a review by Awh, Vogel, and Oh (2006).

Interaction between attention and working memory

It has been suggested that attention is “a gatekeeper that determines which items will occupy the limited workspace within working memory” (Awh et al., 2006). In a paradigm called Attentional blink it in which participants are to identify and report two visual targets rapidly presented following each other. Typically in this paradigm is that processing of the second target is impaired for over 100 ms. Awh, et al. argues that the effect of attentional blink is reflecting a bottleneck in the encoding into WM which will result in the impairment of the second target. This would, in Awh and colleagues view, be a type of goal-driven encoding that reveals one aspect of attentional control. Moreover, it has been found that semantic information in the second target will enter working memory and, therefore, be processed. The integrity of stored representation within WM is further argued be determined by internal shifts in attention.

Furthermore, it has been suggested that covert shifts of spatial attention could facilitate information held in spatial working memory in the same manner that is covertly articulating has been shown to aid maintenance of information within phonological WM. This is called the attention-based rehearsal hypothesis. Moreover, holding an object from the environment will also lead to attentional capture from a subsequent presentation of that object. Both holding spatial locations in WM and spatial attention show overlapping neural substrates. The areas that Awh, et al. points out that there are overlapping areas of the frontal and parietal cortex between spatial WM and spatial attention. Moreover, the lateral intraparietal sulcus (LIP) has been found to be activated by both selective attention and working memory. In monkeys LIP has been found to be activated when remembering locations (e.g., Bisley & Goldberg, 2003).

However, in the Visual Search paradigm, data has been collected that does not follow the attention based hypothesis. In this paradigm, the participants are to hold an object in WM matching a distractor in a search array in half of the trials. If objects in WM would capture attention in an obligatory manner search rates should be slower when the distractor and the object held WM matched. This effect has not been found in many studies. Awh et al., (2006) suggests that objects in memory can indeed capture attention but this effect can be suppressed by other interactions within the WM.

Discussion

That there is an interaction between working memory and attention seems to be quite clear. However, one might wonder in which direction this interaction is taking place. There are other researchers that have focused on working memory capacity (WMC) and attention. It has been found that people with high WMC are less prone to get distracted by the presentation of distracting sounds (Cowan et al., 2001; Sörqvist, 2010). Moreover, it has been found that low people with WMC show greater proactive interference, worse performance in antisaccade tasks, the Stroop task, and more prone to be distracted by the dichotic listening task (see Engle, 2002 for a review).

Furthermore, ADHD, which is an attentional disorder, is related to less activity in the dorsolateral prefrontal cortex (DLPFC), intraparietal sulcus (IPS) and supplementary motor area (SMA) (Konrad & Eickhoff, 2010). Individuals with ADHD also often have low WMC which has led some researchers to suggest that it is the WMC that is one of the problems related to inattention. Furthermore, in a study examining the neural correlates of the executive functions the intraparietal sulcus has been also suggested to be related to amodal selective attention to relevant stimuli and suppression of irrelevant external stimuli (Collette et al., 2005). That is, the intraparietal sulcus seems to correlate with the executive function inhibition as well. Indeed, the executive functions have been found highly correlated to WMC (McCabe et al., 2010). Could the intraparietal sulcus be one of the keys here? To be able to sustain attention you most often need to be able to suppress irrelevant information such as people talking, etc.

In conclusion, there is an obvious interaction between attention and working memory but how this interaction is taking place is somewhat unclear. Without the ability to sustain attention it seems hard to maintain items in working memory but there also seems to be a connection between working memory and the ability to selectively attend. It is maybe here some other control functions such as the executive functions come to play? It seems that there are a plethora of psychological constructs that might share the same underlying brain structures. Personally, I would prefer that researchers united on a few constructs. Finally, more research in this area of interactions between attention and working memory is needed.

References

Awh, E., Vogel, E. K., & Oh, S.-H. (2006). Interactions between attention and working memory. Neuroscience, 139(1), 201–8. doi:10.1016/j.neuroscience.2005.08.023

Collette, F., Van der Linden, M., Laureys, S., Delfiore, G., Degueldre, C., Luxen, A., & Salmon, E. (2005). Exploring the unity and diversity of the neural substrates of executive functioning. Human brain mapping, 25(4), 409–23. doi:10.1002/hbm.20118

Conway, R., Cowan, N., & Bunting, M. F. (2001). The cocktail party phenomenon revisited: the importance of working memory capacity. Psychonomic bulletin & review, 8(2), 331–5. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11495122

McCabe, D. P., Roediger, H. L., McDaniel, M. a, Balota, D. a, & Hambrick, D. Z. (2010). The relationship between working memory capacity and executive functioning: evidence for a common executive attention construct. Neuropsychology, 24(2), 222–43. doi:10.1037/a0017619

Konrad, K., & Eickhoff, S. B. (2010). Is the ADHD brain wired differently? A review on structural and functional connectivity in attention deficit hyperactivity disorder. Human brain mapping, 31(6), 904-16.

Sörqvist, P. (2010). High working memory capacity attenuates the deviation effect but not the changing-state effect: further support for the duplex-mechanism account of auditory distraction. Memory & cognition, 38(5), 651–8. doi:10.3758/MC.38.5.651

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