Selected Neurophysiological Methods for Marketing Research

Electroencephalography

Brainwaves have been observable since the mid-seventeenth century, beginning with the discovery that humans were controlled by electric impulses. A few more memorable events had to follow-such as Galvani's observation of a dead frog's leg moving-before the first electroencephalograph was constructed in the early twentieth century. This device measures the frequency of electric current in the brain using electrodes attached to the subject's head. The frequencies represent brainwaves according to their differing lengths.

It has been well established that patterns of brain activity are closely correlated with behavior and cognition (Alwitt 1985). Nunez and Srinivasan (2006) posit that electroencephalography (EEG) thus offers a "window into the mind," because it registers variations in brainwaves produced by the cortex. The first regular EEG studies started to appear during the 1980s. In a study of advertising content using EEG, Alwitt concluded that "the results of this analysis are an encouraging first look at the relationship between ongoing events and EEG-recorded brain reactions. The topic certainly warrants future research" (Alwitt 1985, p. 216). Thus EEG research in advertising has provided empirical evidence that certain aspects of consumer cognition and emotional response to advertising messages (even below conscious awareness) can be monitored successfully in real time and analyzed. However, Olson and Ray (1985) argue that EEG responses to advertising only provide useful information if they test specific hypotheses about the processes used by viewers. Thus EEG has not been considered as a general evaluative measure of advertising effectiveness.

The difference between early studies and the current research stems from the ease with which information can be obtained and analyzed. Modern computers are much more advanced, and we have considerably more sophisticated statistical programs, which use high-level technical computing languages and interactive environments for data visualization, analysis, and numeric computation. New technical possibilities contribute to both basic and applied EEG research. More recently EEG has helped assess marketing stimuli such as media involvement (Swartz 1998), the processing of television commercials (Rothschild et al. 1986), and the prediction of memory about components of televised commercials (Rothschild and Hyun 1990). Nearly a century after its first public demonstration, EEG has become a very popular method used by cognitive neuroscientists, neurologists, psychophysiologists, and neuromarketers as a noninvasive, relatively inexpensive method to measure brain activity. However, EEG has limited anatomical specificity and can only gather information from the cortex, though it offers very high temporal resolution. Other techniques (e.g., functional magnetic resonance imaging) suffer time resolutions of a few seconds, whereas EEG offers a submillisecond resolution (Huettel, Song, and McCarthy 2004). Therefore, researchers can detect changes in brain activity precisely, connected to rapidly changing stimuli.

Facial electromyography

Another psychophysiological technique used in market research is facial electromyography (EMG), which evaluates the physiological properties of facial muscles. The three muscles studied most extensively are the corrugator supercili, zygomaticus major, and orbicularis occuli. This method offers a powerful instrument to test voluntary (zygomaticus) and involuntary (corrugator and orbicularis) facial muscle movements, which may reflect the conscious and subconscious expression of emotions (Dimberg, Thunberg, and Elmehed 2000; Cacioppo et al. 1986; Cacioppo, Tassinary, and Berntson 2000; Larsen, Norris, and Cacioppo 2003; Ohme, Matukin, and Osiecki 2008). Facial EMG can study both emotional expressions and social communication. Some researchers also have managed to adapt EMG to track consumer reactions to advertising. For example, Bolls, Lang, and Potter (2001) show that zygomaticus muscle activity is stronger during radio advertisements with a positive emotional tone, whereas corrugator muscle activity is greater during ads with a negative emotional tone. Hazlett and Hazlett (1999) compare emotional reactions to television advertisements measured with facial EMG versus self-reported scales and find that EMG offers a more sensitive indicator of emotional reactions, such that facial EMG responses relate closely to emotion-congruent events during ads. They also find that compared with self-reports, facial EMG measures relate more to brand recall measures administered five days later. Thus, they conclude, "EMG measures can reflect a qualitative richness and complexity of the viewer's emotional response that self-report cannot and at the same time offer precise and continuous qualitative data" (Hazlett and Hazlett 1999, p. 19).

Skin conductance

A widely described and well-known measure of psychophysiological reactions is the measurement of skin conductance (SC). This method is based on the analysis of subtle changes in galvanic skin responses when the autonomic nervous system (ANS) is activated. Because an increase in the activation of the ANS is an indicator of arousal, SC can be used as a measure of such arousal (Ravaja 2004). In advertising research, measurement of SC is scarce, though some researchers, while testing other emotion measures, have used SC as a validation tool (Aaker, Stayman, and Hagerty 1986; Bolls et al. 2001). Citing interviews with market researchers who have applied SC and practitioner case studies, LaBarbera and Tucciarone (1995) conclude that SC predicts market performance better than self-reports, though they also formulate important guidelines for equipment and statistical formulas that should be adopted in SC research designs. Moreover, LaBarbera and Tucciarone argue that many previous SC studies in advertising (mostly conducted during the 1960s) failed to identify any effects because they lacked sufficiently sensitive equipment or accurate statistical protocols, which prevented them from separating "noise" from true arousal response. Individual variation also is apparent in SC. Today, technological advancements and complex statistical programs help overcome such difficulties, though a major limitation of SC remains: It cannot determine the direction or valence of an emotional reaction but merely measures the degree of arousal. Thus, both very pleasurable and very repellant advertising stimuli can evoke large SC responses (Hopkins and Fletcher 1994).

Date: 2016-01-14; view: 793