Attention window refers to our breadth of attention, including horizontal breadth, vertical breadth and diagonal breadth. In lay language, it represents the size of a display that we can attend to (i.e., imagine there are 2 players in front of you, but one is walking left and the other is walking right. When we can no longer focus our attention both players, this represents our maximum attention breadth in the horizontal direction).
Stefanie Huttermann, Daniel Memmert and Daniel Simons investigated whether sport experts possessed a larger attention window. Their hypothesis was based on the fact that many sports require breadth of attention in order to be successful. Hence, an adaptation of becoming an expert in sport might be an enlarged attention window.
Their hypothesis extended to the type of sport played. For experts in sports that emphasised horizontal breadth attention (e.g., soccer), a larger breadth was expected in the horizontal direction. Conversely, a larger breadth in the vertical direction was predicted for sports that emphasised vertical breadth of attention (e.g., volleyball).
Three experiments were conducted to test these hypotheses. In each experiment, participants completed an attention breadth task (see figure below). The task required participants to watch a screen whereby stimuli was placed on either side of the screen (left-right, up-down, or diagonal). The stimuli included light grey triangles, and participants had to recall the number of light grey triangles on either side of the screen. The distance between the stimuli varied throughout the task. This allowed for the measurement of maximum breadth.

Experiment 1
12 sport experts and 10 novices participated in the study. All participants played team sports. Experts had >10 years of intense training in a particular sport, whereas novices had only played sport for 3 years (on average).
Results revealed that sport experts possessed a greater attention window than novices by approximately 30%.
Experiment 2
56 sport experts participated in the study. 30 participants played sports that were deemed to demand horizontal breadth of attention (handball or soccer), while 26 participants played sports that were deemed to demand vertical breadth of attention (basketball or volleyball).
Results showed that the soccer and handball players possessed a slightly greater attention breadth in the horizontal direction compared to the basketball and volleyball players (approx. 5% larger). Comparatively, the basketball and volleyball players displayed a larger breadth of attention in the vertical direction compared to the soccer and handball players (approx. 9% larger).
Experiment 3
25 sport experts and 12 non-athletes participated in the study. Of the 25 experts, 13 played soccer or handball (horizontal breadth of attention emphasised) and 12 played basketball or volleyball (vertical breadth of attention emphasised).
This experiment replicated the results of experiments 1 and 2. Sport experts possessed a larger attention window compared to novices, and the breadth of attention in the vertical and horizontal directions was a function of sport-specific expertise.

Implications
The results highlight expertise differences in the size of the “attention window”. However, as the authors state: “we cannot infer a causal link between spatial distribution of attention and experience playing a particular sport. Expertise can be viewed as an optimal adaptation to task constraints, and our subjects showed a spatial distribution of attention that matched the demands of their sport.”
Understanding how this capacity is developed is the next step in this research.
Reference