Alcohol and the Stroop Effect

Introduction

The cognitive difference between people who regularly abuse alcohol and those who drink socially has been explored using a range of investigatory paradigms. One of the approaches used was the emotional Stroop paradigm (Williams et al., 1996). When the word meaning and ink color are different the color naming is found to be slower than when the semantic content of a word is neutral. This slowing is known as the Stroop effect, from which it is concluded that an attentional bias has developed for concern-related information carried by some words. Through the routine use of controlled designs, it has been repeatedly shown that individuals who abuse or depend on alcohol show larger alcohol-related interference effects than individuals who do not (Johnsen et al., 2004). The attentional bias towards alcohol-related is one of numerous findings that may help explain the reason why such individuals have particular difficulties in reducing their alcohol consumption even if their consumption is problematic. This also may aid in explaining why, after successfully controlling consumption, a return to abusive levels of consumption so frequently occurs (Cox, Yeates Regan, 1994). The importance of an alcohol-related attentional bias is that it potentially impacts on consumption decisions in two distinctly different ways. First, it has a potentially �direct’ effect, influencing the flow of thought towards decisions to seek out and consume alcohol, and is principally an explicit, conscious process (Goldman et al., 1999) and not necessarily related to urges and craving. Second, it has a potentially �indirect’ effect in which the stimuli themselves do not impact directly on the flow of thought but generate responses that do, and which in turn may prompt decisions to seek and consume alcohol, and is initially an unconscious, implicit process (Stacy,1997), usually with a conscious output. Research on alcohol-related attentional bias with the Stroop has not been confined to individuals who abuse or depend on alcohol. Interest in a wide range of alcohol cognitions along the entire consumption continuum means that cognitions in the regions of use and misuse have become a research focus in their own right, and not just as controls for helping understand cognitions associated with abuse and dependence (Bruce, Jones, 2004). However, whereas attentional bias appears to be a frequently found feature of individuals who abuse and depend on alcohol compared to those who do not, the subsequent evidence for its presence in heavier compared to lighter users or misusers from Stroop experiments is limited. Using the Stroop paradigm, it has been confirmed that the bias might only become evident under the conditions of a test in which additional, explicit alcohol cues are present (Jones and Schulze, 2003). More direct support for an attentional bias among social drinkers has recently been provided by another group (Jones et al., 2002, 2003), who also found an attentional bias in �heavier’ social drinkers compared to �lighter’-drinking controls. However, unlike Cox et al. (1999, 2003), Jones and Schulze (2000), Sharma et al. We will demonstrate if we can obtain the same results.

Classic Stroop Effect

In 1935, John Ridley Stroop investigated interference in serial verbal reactions. In one of his experiments, participants were presented with names of colors were printed in different ink colors. The word meaning and ink color were either the same, for example the word red printed in red ink, or they were different, for example the work green printed on yellow ink. The participants were there then instructed to name the ink color of each word, ignoring the word itself. Stroop effect refers to the finding that participants are slower to name the ink colors when they are different from the meaning of the word then when they are the same. The evidence also suggests that the classic Stroop test has adequate test–retest reliability (Siegrist, 1997). The paradigm and its widespread use have driven many authors to offer explanations that account for the classic Stroop effect. “Today most psychologists think of the Stroop task as a hallmark measure of attention, not learning” (MacLeod, 1991, p. 187). One explanation that accounts for the Stroop effect asserts that processing word meaning, is more automatic than processing ink color. (Mac-Leod & Dunbar, 1988). Cohen, Dunbar, and McClelland (1990) stated that the more often a particular processing pathway was activated, for example reading a word, the more easily it was to be used for encoding the well-learned dimension in the presence of novel stimuli, in this case the colors of the ink. This is especially true when a better learned dimension must be ignored in order for a less well-learned dimension to be responded to. The processing bias could