When we are paying attention to something, we often do so to the exclusion of everything else. Think about when you go food shopping. You have your shopping list in hand and walk up and down the aisles looking for the items that you need. You pass by thousands of other items without noticing them at all, even though from a cognitive perspective, your eyes are seeing them and noting them. This is called “selective attention”. Selective attention has also been described using the term “the cocktail party effect.” It is the phenomenon by which you can be at a party, surrounded by multiple conversations, music, the clinking of glasses, yet still focus on just one conversation to the exclusion of all others. Our brain has a limited capacity to pay attention to what is around us, so we select what we will attend to, to the exclusion of other things. (Vanderbilt University)
Selective Attention and Inattentional Blindness
You have probably seen the now-famous video in which a group of young people are passing a basketball around between them while a person in a gorilla suit strolls into the middle of the scene, stops and thumps his chest, then exits. The video is a depiction of how selective attention works. The viewer is asked to count how many times the basketball is passed between those in the group who are wearing white tee shirts. In the midst of counting the passes, the viewer becomes so intent that they miss the gorilla-costumed participant. (The Invisible Gorilla) This is a form of selective attention known as inattentional blindness. We are so focused on what is important to us that we become unable to see other important items in our environment. (Columbia University) This example of selective attention has been viewed by more than 15 million people (and you can view it here), and it is intriguing. But it belies the fact that selective attention and inattentional blindness can also be life threatening. A study conducted by Harvard Medical School and Brigham and Women’s Hospital asked 24 radiologists to review a lung X-ray to find whether a specific type of abnormality was present. The lung image they were shown contained a picture of a gorilla that was 48 times the expected size of the nodule they were asked to locate – only 17 percent of the radiologists made note of the gorilla, despite looking directly at its location on the film. (Harvard Medical School) The study, though frightening, was viewed as an accurate presentation of the limits of human perception and attention.
Differing Theories on Attention
There have been a number of different theories proposed for how we select which stimulus to attend to. The filter method suggests attention as a bottleneck, in which we make a decision at the onset of multiple stimuli as to which one we will select to attend to. The idea is that by discriminating against information that we view as unimportant, we prevent ourselves from becoming so overloaded with information that we are not able to process what is important. This theory has been supported by a number of experiments in which researchers have asked test subjects to listen only to information coming in one ear while other information was also being heard by the other. However, further testing of this theory supported the attenuation theory that suggests that though we may reduce our attention to competing, stimuli, we are still listening.
Memory Selection and the Cocktail Party Effect
The notion that we are able to make a conscious selection of what to pay attention to is further contradicted by the cocktail party effect. Not only are we able to single out a single conversation to pay attention to within a distraction-filled environment: we are also able to be distracted from what we are attending to if it has critical meaning to us. So we may be listening intently to a story being told by a friend, but when somebody across the room mentions your name or a subject of particular interest to you, your attention is diverted to that conversation. This is known as “memory selection”, and it points to the importance of meaning and content in transferring information from being nothing but sensory stimuli into something that gets stored in our short term memory. (Berkeley) An interesting study conducted at Vanderbilt University provides an example of memory selection
Selective Attention, Encoding Memories, and Attentional Capture
All of our experiences have an impact on our cognitive brain, but only a small portion of what we experience is remembered. This is a function of our selective attention. Though the brain automatically encodes everything that we are cognitively exposed to, we are unable to retrieve that information later, either because of a storage failure or a retrieval failure. What is best remembered is what is most effectively encoded, and studies have shown that it is what we selectively attend to that has the strongest memories. (Stanford University) Conversely, this means that in order to store what is important to us in our memories for later retrieval, we have to first pay attention. This is known as “attentional capture.” An interesting study conducted at Vanderbilt University provides an example of memory selection, attentional capture and how memories are encoded by documenting something that most people will find familiar – the way that we remember images of food when we are particularly hungry. In the study, participants were asked to refrain from eating for several hours before being shown a series of images. They were instructed to look for photos of landscapes and ignore those that were of other scenes, including images of food, images evocative of romance, and other neutral images. When tested, the group not only detected and remembered the photos of food, but they did so to the detriment of what they were supposed to be seeking.
Distractions and Memory
Do you listen to music while you are studying? Though many people keep music on at all times in the belief that it improves their focus, studies of selective attention – and its impact on memory and learning – have shown that it does just the opposite. People who were asked to memorize a list of names had a decreased ability to do so when there was music playing while they were trying to learn them. This is because music is tied in to our associative memory, and can trigger a recollection that distracts us from the task at hand. It takes our attention away, and thus interrupts our ability to encode what we had been attending to. (Boston University). Similarly, interruptions can interfere with our memory of what our intention was. A study of medical professional found that when nurses were constantly distracted from a task by interruptions, they were far more likely to forget what they had been doing or where they were in the process. These lapses in memory can lead to life threatening mistakes in clinical settings. (Institute for Safe Medication Practices)