Height and End-State Comfort Effect With an Overturned Glass Task
Thursday, April 3, 2014
Exhibit Hall Poster Area 1 (Convention Center)
Casey Breslin, Temple University, Philadelphia, PA and Kristina M. Slog, Thomas Jefferson University, Philadelphia, PA
Background/Purpose: When grasping an object within the natural boundary formed an individual’s maximum arm extension, a majority of individuals grip with an awkward and uncomfortable starting position in order to end the movement in a more comfortable state, known as the end-state comfort effect (ESCE). As an individual’s height influences how far an arm can be extended, the purpose of this study is to determine the probability that a grasp indicating ESCE will be used by individuals of shorter stature (less than 160 cm tall) when an overturned glass is located on a high shelf. We hypothesize that shorter participants will prefer to avoid using the ESCE and grasp the glass initially with a comfortable thumb-up position and end with a thumb-down position.
Method: Participants (n= 25) shorter than 160 cm were instructed to climb a step stool to reach an overturned drinking glass on a high shelf, turn the glass right-side up, and fill it with water. Videotape data of the initial grip the participants used to grasp the overturned glass was coded for analysis.
Analysis/Results: A majority of participants elected not to use an ESCE grasp on trials 1 (64%), while during trials 2 and 3, a slight minority (44% and 48%, respectively) elected not to use the ESCE. A Cochran’s Q test, indicated that participants did not choose an ESCE grip over top-and-twist, start-state comfort, and supination grips across all three trials (Q (2) = 6.00, p= .050).
Conclusions: Thus, our hypothesis was supported as individuals of shorter stature seem to prefer a grip violating the ESCE to manipulate an overturned glass on a high shelf.
