Attention – a limited resource?


Attention can be defined as a concentration of mental activity that allows you to take in limited portion of information available both of your sensory world and memory. Attention work as a gatekeeper. If certain information do not get attention, it has no existence in your cognitive system. This emphasises the view of attention as a limited resource.


Attention tasks

The fact that attention is divided, explains why attention might be seen as a limited resource. In divided-attention task person is trying to pay attention to two kinds of simultaneous messages at the same time and tries to respond to these messages appropriately (for example teacher’s lecture and nearby conversation). In both tasks accuracy suffer. When tasks involve movement, speed can lower down (e.g. speaking in a phone when walking -> walking will get slower).

If person is multitasking, he is trying to concentrate on two tasks at the same time. It restricts the limits of attention and working and long-term memory. For example, when a person is driving a car and speaks on a phone (even when with hands-free), attention what happens in visual field is reduced.

Selective-attention task allows people to to pay attention to certain kinds of information, while ignoring other ongoing information. This makes our everyday life a bit easier. Selective attention also emphasise, that attention is seen as a limited resource. There are four kind of selective-attention tasks that clarify in which ways our attention is limited and selective. These are dichotic listening, the Stroop effect, visual search and saccadic eye movement. Next I am going to present these and show, how they support the fact that attention is limited.

Dichotic listening

Refers to a situation when you are trying to concentrate to hear a certain message but at the same time you register loud sounds from nearby conversation. In laboratory, dichotic listening task is studied by asking participants to use a headphones. They are asked to shadow words (repeat after speaker) what they are hearing to the other ear (listening task), but in the same time they hear another message into another ear (unattended second message). If a participant makes mistakes in shadowing, a researcher knows that he is not paying appropriate attention to the listening task. People notice only very little about the unattended second message.  In the experiment they didn’t notice, when the language was changed in the unattended message. However, they did notice if a gender of a speaker changed or when their own name was mentioned. In general, people can process only  one message at the time in dichotic listening task and this supports the claim that attention is limited resource. However, people are more likely to process the unattended message when: both messages are presented slowly, the main task is not challenging and the meaning of the unattended message is immediately relevant (Cocktail-Party effect).

The Stroop effect

Is named after James R. Stroop (1935) who developed this well known task that demonstrates selective attention. According to Stroop effect, people take longer time to name the ink colour when that colour is used in printing incompatible word. For example word ”yellow” is printed with blue colour. People may require about 100 seconds to name the ink colour of 100 words that have incompatible colour names. Stroop effect demonstares selective attention because people take longer time to pay attention to actual colour when they are distracted by another feature of the stimulus (the meaning of the name self).


Visual search

Is the third selective-attention task that shows, how our attention is limited. In visual search -task a person must find a target in visual display that has distractions. People are much more accurate to identify a target if it appears frequently. Visual search handles isolated or combined features (the isolated-feature/combined-feature effect) and targets in which certain feature is present or absent (the feature present/feature absent effect).

In the isolated-feature/combined feature effect if the target differs from the irrelevant items in the display with only one feature, observer could quickly to detect the target.  Number of the targets is irrelevant.


It takes more time to detect a target when it is combination of two properties: it is harder to find blue X among red Xs, Os and blue Os. It takes more time because a person has to use serial processing concentrating to each item at time (focused attention). Number of the targets becomes relevant because time to find a target increases when the number of items increases.

The feature present/feature absent effect refers Treisman’s and Souther’s study (1985), that people can typically locate a feature that is present (positive)  more quickly than a feature that is absent (negative). Treisman and Souther noticed in their studies (circle with and without the line) that one item with a feature seems to pop-out easily from visual display (distributed attention). The search is rapid when we are searching for a specific feature that is present. When people are searching a feature that is absent they typically have to examine every item at a time. This task is more challenging and takes more time. When the number of items increase the time for search increases as well.



Saccadic eye movement

Visual scenes contain far too much information to be apprehended in a single glance. These limitations mean that effective vision depends on saccadic eye movements and attention, working together in a coordinated fashion, to select the objects, features or regions with the greatest momentary need for limited processing resources. To increase the clarity about what we see, our eyes must continuously and frequently move about. These rapid eye movements are called saccades and they allow us to select what we want to pay attention to visually. The fact that we use saccadic eye movement clarifies the claim that our attention is limited; we use selective way for choose objects from our visual environment as a response to huge amount of information that is available.

As you can see the previous selective-attention tasks clarify, that attention is a limited resource. Its selective nature causes it to be limited. However, limited attention is useful for us in our everyday lives because it helps us to  manage under the great amount of information.


Matlin, Margareth W. (2013). Cognitive Psychology, International Student Version. (8th edition). Wiley.


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