# Collaborative Facilitation and Collaborative Inhibition in Virtual Environments
## 1 Introduction
### Evidence from Collaborative Memory Tasks  
The collaborative inhibition and facilitation effects have been a focus of studies on collaborative memory tasks. Some of them have applied the DRM paradigm [11] that was also used in this study. In the DRM paradigm, individuals learn lists with semantically related words (studied words: e.g., apple, orange, berry etc.). The most \"common\" word of the category is removed. This omitted word is called \"critical lure\" (e.g., fruit). With DRM paradigm, it is possible to evaluate the false recall of both the critical lure, as well as of other words (i.e., non-studied words) during collaboration. Studies that have assessed collaborative recall performance indicated mixed results [12]. For instance, some experiments (experiment 1 and 2) adopting the Deese-Roediger-McDermott (DRM) paradigm found that collaborative groups performed worse than nominal counterparts due to disorganized retrieval [13]. Another research indicated that collaborating groups performed better than individuals by recalling more presented words and they resulted in less false memories than the nominal condition [8]. More recently, a study by [PERSON] et al. [12] showed that the recall of the presented words was greater for the nominal condition than collaborative condition but this latter condition resulted in less false memories than the nominal condition. Some researchers explain such contrasting results through different encoding strategies which people apply to categorize lists of studied words. Using category lists (concrete words), [PERSON] and [PERSON] [14] evaluated the influence of the encoding strategy (imagery, word-whispering, control) on memory performance through four experiments that differed in the type of recovery (recall, recognition) and duration of the encoding (self-paced, fixed duration). Overall, results suggested a more accurate memory performance for imagery encoding than word-whispering encoding. A remarkable result was related to the control group that showed a tendency to be more accurate. This result was explained by the researchers through [PERSON]'s dual coding theory [15] that argues that it is possible to spontaneously evoke mental images of encoded concrete items and, therefore, the resulting verbal and visual codes could be exploited during retrieval. Unlike the DRM paradigm [11] which may use both abstract and concrete word lists, the latter study by [PERSON] and [PERSON] [14] used categorical study lists that include only concrete words that are equally easy to imagine. As suggested by [PERSON] et al. [16], _\"the complexity of the task was identified as an important factor for determining whether collaborative learning will or will not be effective and/or efficient as compared to individual learning\"_ (p. 39). In particular, an individual will be able to benefit from collaboration with others the more complex the learning task will be. In this case, the greater intrinsic cognitive load of the complex task will be reduced by its division among group members and, therefore, collaborative learning might lead to better results than individual learning. On the contrary, groups might perform as individuals or worse when the task complexity decreases [16]. Another variable that may influence false recall is the group size. Using DRM lists as stimuli, [PERSON] and [PERSON]'s study [17] aimed to examine the effects of group size (individuals, pairs, trios and quartets) and group pressure (high pressure--turn taking recall; low pressure--free for all; nominal recall) on critical lures, nonstudied intrusions and studied words recall. Results showed that, regardless of group pressure, critical lures, nonstudied intrusions and studied words increased with group size. High pressure group members falsely recalled more critical lures and intrusions. In accordance with collaborative inhibition, nominal group members recalled more studied words than individuals of free for all and turn taking groups.