This concept can be used to describe my trip to the grocery store. When walking with your cart down the crowded frozen food aisle, you are transporting your body down the aisle in order to get to the chicken nuggets. Object manipulation can be described by both pushing the cart and opening the door of the freezer while picking up the bag of chicken nuggets. The frozen food aisle always seems to be crowded therefore you must navigate around other shoppers who are regulatory variables. The other shoppers influence your movements as you walk down the aisle preventing you from walking in a straight line to the chicken nuggets. The regulatory conditions while grocery shopping are variable. If you go to the store on Saturday or Sunday, you will probably experience a lot more shopper traffic on your way to the chicken nuggets. If you wait and go on Monday night you may experience less shoppers blocking the path between you and your chicken nuggets. Intertrial variability is even evident if you have to go down the same frozen food aisle several times in the same grocery trip. The shoppers and the positions of the carts in your way are always changing. 

I played volleyball throughout my entire high school career. A whistle is used by the up-referee as the warning signal for the serve. The server then serves the ball over the net to the opposite team. The serve is the stimulus that is presented signifying the start of the volley. The time between the whistle and the serve is the foreperiod which may differ between different players due to technique. During the premotor reaction time, the defensive players send the information that the ball has been served to their muscles in order to be ready to pass the ball. Force is built up in the muscles of both the arms and legs of the players as they prepare to pass the ball approaching them. Muscles are activated to be able to carry out the passing action as well as to move to a different location in the case that the serve is not directly to them. If the ball is approaching the defensive player at a high height and two feet to the left, the player must adjust. This marks the start of the movement time. The player must move their feet to the left in order to adjust to the location of the ball as well as change the location of their arms to above their head in order to set the incoming ball. Once the ball makes contact and is set to the setter, the response ends, signifying the end of the movement time as well as the response time. 

When practicing a dance routine, attention shifts throughout the entire routine. At my high school, the senior girls put together a senior girls dance for the end of the year. We practice for weeks before the performance. Learning a dance routine is very difficult to learn including both individual parts and synchronizing as a group. Attention must shift between all four quadrants of attentional focus in order to learn the routine. The girls were separated into two groups that performed similar, but different routines. Each group took turns practicing while the other group watched. Broad/external attention is demonstrated when one group sat out and watched the other group because we were learning by looking at the big picture. Narrow/external attention is used when the focus is on one of your dance partner’s footwork in order to synchronize with them. When practicing with no music, narrow/internal attention is used in order to set a beat or rhythm in your head in order to learn one specific arm movement. Before the performance we all experienced broad/internal attention in order to picture the entire routine in our minds to minimize errors before the routine began. 

In basketball if you only practiced shooting from the free throw line, you would most likely get really good at shooting from that specific spot on the court. If you practice from all around the three-point line as well as inside the paint, you will more likely be a better all-around shooter. In high school, this was evident in our forwards who mainly focused their shooting practice inside the paint. These players were less successful at shooting at the three-point line during the game because they were unable to adjust their force and angle of shooting. On the other hand, the shooting guards and the point guards were better all around shooters because they were forced to practice at the three-point line and inside the paint. The larger variety of shooting positions practiced lead to better overall shooting during the game.