Abstract: The mere exposure effect refers to a phenomenon in which people tend to develop a preference for a stimulus merely after repeated exposure to it. Numerous studies have examined the robustness of this effect, with a variety of stimuli. However, most studies used neutral and novel stimuli; few researches found the typical mere exposure effect in initially familiar stimuli. Furthermore, only a few researches used negative stimuli, and the results of those were quite inconsistent. The present study aimed to clarify this issue using neutral and negative Chinese words as stimuli. Also, we investigated whether the mere exposure effect still existed when the stimuli were initially familiar ones.
Before the experiments, 35 Chinese undergraduate and graduate students were recruited to help us obtain neutral word-pairs and negative word-pairs separately as stimuli for Experiment 1 and 2. In each pair subjects didn’t like either of the two words better than the other. In Experiment 1 and 2, two other groups of 30 Chinese undergraduate and graduate participants were separately exposed to neutral (Experiment 1) and negative stimuli (Experiment 2) subliminally. Each word was presented for 14ms, followed by a 30-ms mask. For each pair of words, one word was presented only once, and the other 6 times. After this study phase there was a test phase, in which participants should finish a forced-choice preference/recognition judgment. They were asked to examine each word-pair and to choose the word they liked better (preference judgment) or the word they had seen in exposure phase (recognition judgment) within 2000ms.
The results indicated that the recognition scores of neutral words were not significantly different from chance level, and neither were the negative words during the recognition judgment, which indicated that the exposure to stimuli was really subliminal. Repeated neutral exposure led to more liking during the preference judgment, with the preference scores significantly higher than chance level, while repeated negative exposure did not.
Therefore, it can be concluded that when the stimuli were initially familiar ones and were presented in a subliminal way, the typical mere exposure effect can only be observed in neutral stimuli rather than negative ones. We used levels-of-processing model to explain the mechanism of this phenomenon in the discussion session.

Key words: mere exposure effect (MEE), subliminal exposure, preference, neutral emotion, negative emotion