Arousal refers to the state of being alert physically and internally. Various body system and hormones may contribute to alertness (20). The concept of arousal may include the physical, psychological, physiological, and emotional arousal. In the study of memory, emotional arousal is focused on more than the other types of arousal. MacKay and Ahmetzanov (25) conducted a study on the relationship between emotional arousal and memory by using taboo stroop paradigm. They predicted better memory for taboo words (which were more emotionally arousing) than neutral words. It was found that the participants performed better in experimental conditions that were associated with emotionally arousing words (taboo words) than the conditions with neutral words (26). This result complements the study of Heuer and Reisberg (27), that found better retention in long-term recall with a high level of emotional arousal. Similarly, a high level of arousal leads to enhancement of both short-term and long-term memory. In an experiment conducted by Corteen (cited in 27), which used aurally presented words, it was reported that higher recall was found after 20 minutes and two week delays. The same result was reported in an experiment which used a single arousing word. Recall performance was found to be better with words that have arousal effect than non-arousal words. However, there was also evidence on the detrimental effects of arousal especially on short-term retention. For instance in learning, the participants who have high arousal effect remembered better in the delayed recall rather than shortly after learning process. According to Kleinsmith and Kaplan (28), words that can produce greater arousal effect were better remembered after one week than two minutes after the learning process. Thus, from the studies mentioned above, the level of arousal evoked by environmental stimuli can have a significant effect on memory performance in whether the short-term or long-term memory storage.