How much visual information can we hold in mind at a given time?
Despite our intuition, studies show that we can only hold a limited amount of information (i.e., 3 or 4 simple object worth of information!!) at a given time (Fukuda, Awh, & Vogel, 2010). This capacity limitation of our mind is called visual working memory (VWM) capacity. Studies also show that individuals vary in this capacity limit; some individuals can maintain 4 or more objects while others can maintain fewer than 2 objects.
but,,, WHY and HOW?
We showed that a major portion of these individual differences arise from individuals’ ability to control what gets access to capacity-limited VWM (Fukuda & Vogel, 2009, Fukuda, Woodman, Vogel, 2015). To illustrate this point, consider two travelers with the same suitcase going to a ski resort. One traveler is very good at selecting what to take to the trip, so her suitcase is packed with necessary stuff to enjoy the trip (e.g., ski jacket and pants, cameras, oh and of course, gloves!). The other traveler, however, is not so good at choosing what to take. So, his suitcase contains stuff that is not necessary for skiing (e.g., a pair of flip flops that he took to a summer vacation 5 months ago) and may not have room for clothes that keep him warm and cozy for skiing… As a result, although they have the same suitcase, the functional storage space for the ski trip is very different between them.
Okay,,, but why and how did he leave the flip flops in the suitcase?
We showed that this is because he is slower at disengaging his attention from a task-irrelevant information after his attention is accidentally captured by it (Fukuda & Vogel, 2011). To illustrate this point, let’s go back to the same example. When he opened his suitcase to pack up for the ski trip, he found the flip-flops left from the summer vacation. They brought him back the fun memories from the trip to the beach, and he indulged in them for a bit, forgetting about what he was doing. As a result, the flip flops were left in the suitcase. What about her? When she found the flip flops, they did bring back the fun memories, but she quickly realized that she was packing for the ski trip, and was able to remove it from the suitcase. As a result, her suitcase is packed with all she needs to enjoy skiing comfortably!
Hmm,,, is he always bad at attentional control?
No, not always! Most of the time, he can go back on track at what he was doing. This failure of attentional selection seems to occur occasionally (Adam, Mance, Fukuda, & Vogel, 2015), and when given proper feedbacks, he can reduce the frequency of such failure (check out this AWESOME work (Adam & Vogel, 2016) by Kirsten and Ed at the University of Chicago) !