Hitting is Contagious: Experience and Action Induction Rob Gray University of Birmingham Sian L. Beilock University of Chicago In baseball, it is believed that “hitting is contagious,” that is, probability of success increases if the previous few batters get a hit. Could this effect be partially explained by action induction—that is, the tendency to perform an action related to one that has just been observed? A simulation was used to investigate the effect of inducing stimuli on batting performance for more-experienced (ME) and less-experienced (LE) baseball players. Three types of inducing stimuli were compared with a no- induction condition: action (a simulated ball traveling from home plate into left, right, or center field), outcome (a ball resting in either left, right, or center field), and verbal (the word “left”, “center”, or “right”). For both ME and LE players, fewer pitchers were required for a successful hit in the action condition. For ME players, there was a significant relationship between the inducing stimulus direction and hit direction for both the action and outcome prompts. For LE players, the prompt only had a significant effect on batting performance in the action condition, and the magnitude of the effect was significantly smaller than for ME. The effect of the inducing stimulus decreased as the delay (i.e., no. of pitches between prompt and hit) increased, with the effect being eliminated after roughly 4 pitches for ME and 2 pitches for LE. It is proposed that the differences in the magnitude and time course of action induction as a function of experience occurred because ME have more well-developed perceptual-motor representations for directional hitting. Keywords: baseball, mirror neurons, visual perception, motor control, induction A commonly held belief in the sport of baseball is that “hitting is contagious” (Will, 1990). In other words, if the previous few batters are successful in hitting the ball and getting on base it will increase the probability that the current batter will also get a hit. Indeed Major League Baseball (MLB) statistics provides some support for this belief as batting averages are roughly 50%–70% points higher for a batter following hits by the previous two batters as compared to outs made by the previous two batters (Ross, 2004). It is likely that the effect is driven by multiple factors including pitcher ability (if the previous few batters are successful it is likely that the pitcher’s current performance level is lower), batter motivation (there is more incentive for a batter to get a hit with runners on base because it is likely to result in a run being scored), pitcher pressure (the added pressure of having runners on base may lead to a decline in performance by the pitcher, e.g., Beilock & Carr, 2001; Gray, 2004), and strategy (it is well-known that pitchers throw different pitch types with runners on base, e.g., Williams & Underwood, 1970). The focus of the present study is another potential influence on this effect: action induction. Observing an action performed by somebody else induces in an observer a tendency to perform an action that is somehow related (Katz, 1960). Examples of these types of induced actions, often called “ideomotor movements”, include a person yawning when they observe someone else yawn and a vehicle passenger pressing an imaginary brake as the driver approaches an intersection. Ideo- motor movements can occur both when the observer views the execution of the action (as in the yawning example) and when an observer views only the outcome of the action (as in the braking example). A theoretical basis for induced actions is provided by Prinz’s (1997) “common coding” principle. Common coding sug- gests that actions are planned and controlled by their intended effects. As in earlier feedback-based control theories (see Powers, 1973), Prinz proposed that the governing nodes in motor control hierarchies are intended environmental changes that actions should create. In other words, the perception of an action outcome en- gages the same neural systems involved in the planning of a future action. This link between perception of action outcome and action execution is supported by physiological studies examining “mirror neurons” in the premotor cortex of monkeys (Gallese, Fadiga, Fogassi, & Rizzolatti, 1996). These neurons are active during action execution (as one would expect from a neuron in the premotor cortex) but also when the monkey observes the same action being performed by an experimenter. Could this type of induced action be involved in the “hitting is contagious” effect? There is some evidence that the answer is “yes”. For instance, athletic performance is significantly improved if athletes view videos (just prior to competition) of themselves or somebody else successfully executing an action related to their sport (Leavitt, Young, & Connelly, 1989; Templin & Vernachhia, 1995). Of course, these performance improvements could also be due to many of the other factors described above (e.g., increased motivation or self-confidence). Nonetheless, in more controlled laboratory experiments, evidence also exists for an induced action Rob Gray, School of Sport and Exercise Sciences, University of Bir- mingham, Birmingham, England; Sian L. Beilock, Department of Psychol- ogy, University of Chicago. This research was supported by National Science Foundation Grant BCS-0239657 to Rob Gray and National Science Foundation Grant BCS- 0601148 to Sian L. Beilock. Correspondence concerning this article should be addressed to Rob Gray, School of Sport and Exercise Sciences, University of Birmingham, B15 2TT, United Kingdom. E-mail: r.gray.2@bham.ac.uk Journal of Experimental Psychology: Applied © 2011 American Psychological Association 2011, Vol. 17, No. 1, 49 –59 1076-898X/11/$12.00 DOI: 10.1037/a0022846 49