Changes in EEG Laterality Index Effects of Social Inhibition on Putting in Novice Golfers
Shelley-Tremblay, John F., Shugrue, John D., Kline, John P., Journal of Sport Behavior
Throughout the last twenty-five years studies have examined changes in electroencephalogram (EEG) laterality as elite athletes have prepared to execute a motor act, such as shooting a bow and arrow or rifle, or performing a golf putt (Bird, 1987; Hatfield, Landers, & Ray, 1984; Hillman, Apparies, Janelle, Hatfield, 2000; see Hatfield, Haufler, Hung, & Spalding, 2004 for a review). However, relatively few studies have examined the EEG correlates of performance for novice athletes during a similar preparatory period. This is largely due to the emphasis placed on research designed to investigate "peak" or "ideal" performance, with its direct application to providing a competitive edge in sports (Williams & Krane, 1998).
In addition, while social facilitation/inhibition is one of the oldest and most researched areas in sport psychology, there are virtually no studies that examine how the presence of an audience affects EEG lateralization patterns within the sports literature (see Saarela, 2000; and see Davidson, Marshall, Tomarken, & Henriques, 2000 for EEG and public speaking). This is particularly surprising given the aforementioned emphasis on researching issues relevant to competitive sport, which has as a hallmark the presence of an audience. The current study seeks to expand on the work of Crews and Landers (1993) by exploring the shifts in EEG laterality that occur prior to a golf putt made by novice golfers who were assigned to putt alone and also in front of an audience.
The electroencephalogram represents a record of fluctuations in the electrical activity of the brain recorded from the surface of the scalp. The EEG records potential changes, which are generated by the summed ionic currents of many thousands of cortical neurons. The EEG represents the excitatory and/or inhibitory post-synaptic potentials recorded primarily from the apical dendrites of pyramidal neurons in neocortex. The frequencies of the potentials recorded from the surface of the scalp of a normal human vary from 1 to 50 Hz, and the amplitudes typically range from 20 to 100uV (Neidermeyer & Lopez da Silva, 1999). Four dominant frequency ranges are typically observed: alpha, beta, delta and theta. Theta and delta activity predominate during sleep, and as such, are not reviewed further here. Since the present study focused on participants during a waking state, only alpha and beta were analyzed in the present study and will be reviewed further.
Beta waves are normally seen more diffusely during intense mental activity, and have frequencies ranging from 13 to 30 Hz. Beta waves have the smallest amplitudes of recorded EEG activity (Neidermeyer & Lopez da Silva, 1999). For the present study, beta was broken down into beta 1 (13 to 21 Hz) and beta 2 (21-30), in order to replicate previous research. Beta 2 frequencies seem to be particularly active in schizophrenics and highly anxious performers (Ramos, Cerdan, & Guevara, 2001).
Alpha waves, which range in frequency from 8 to 13 Hz, are sometimes called Berger rhythm, after Hans Berger who first identified them. Alpha waves are generally associated with a state of relaxed wakefulness, especially visible in occipital regions when the eyes are closed. An increase in alpha amplitude in a task has frequently been linked to cortical deactivation (Kimura et al., 2001), especially in the sport psychology literature (Hatfield et al., 1984; Rebert, Low, & Larson, 1984; Crews & Landers, 1993).
Studies of EEG Asymmetry Prior to the Execution of a Motor Act
Several investigations have explored the relationship between EEG asymmetry prior to performing a motor act and subsequent athletic performance. Hatfield and Hillman (2000, p. 362) provide an excellent review of this literature, which begins with the work of Pullum (1977) indicating that better shooting accuracy was associated with an "enhanced" alpha state. …