Behaviorally, some semantic anomalies, such as those used to demonstrate N400 effects in ERPs, are easy to detect. However, some, such as "after an air crash, where should the survivors be buried?" are difficult. The difference has to do with the extent to which the anomalous word fits the general context. We asked whether anomalies that are missed elicit an ERP that could be taken as indicating unconscious recognition, and whether both types elicit an N400 effect when they are detected. We found that difficult anomalies having a good fit to general context did not produce an N400 effect, whereas control "easy-to-detect" anomalies did. For difficult anomalies, there was no evidence for unconscious detection occurring. The results support a qualitative distinction in the way the two types of anomalies are processed, and the idea that semantic information is simply not utilized (shallow processing) when difficult anomalies are missed.

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This study investigates how people adapt to text-based computer-mediated communication (CMC), specifically focusing on how novice users change their communicative strategies over time to achieve effective communication. Twenty pairs of university students completed three collaborative problem-solving tasks (The Map Task;Brown et al., 1984), over a series of days. Their performance was compared with the results from spoken interactions, taken from the Human Communications Research Centre corpus of Map Task dialogues. Task performance by CMC participants was initially poorer when compared to the performance of spoken interlocutors, but improved as they gained experience of the CMC context. Detailed analysis of the process of communication, using dialogue measures and Conversational Games Analysis (Kowtko et al., 1992), shows that effective communication and collaboration was achieved by users of the CMC system after a relatively moderate amount of experience. Participants in the CMC context changed the way in which they gave instructions and interacted over time. They adopted a precise, highly specified style of giving directions which required little interpretation by addressees. This concise style of communication is rarely found in face-to-face or spoken interactions.

880The relative importance of particular parts of a sentence is signaled through devices of information structuring and prosodic stress, which control the focus of information within sentences, as is made clear in an extensive linguistic literature (see, e.g., Gundel, 1999;Halliday, 1967;Jackendoff, 1972;Rooth, 1992). In the present article, our interest is in the cognitive effects of linguistic prominence, which can be manipulated through information structuring devices, such as the it-cleft construction. This construction is illustrated in (1), which shows how an it-cleft structure can signal prominence linguistically.(1) It was Harry who threw the snowball at Mary.This construction consists of a presupposed part-that someone threw a snowball at Mary (Delin, 1992;Prince, 1978)-and a new assertion, that Harry was the person who did the throwing (see, e.g., Hedberg, 2000;Prince, 1978). Use of the it-cleft structure clearly distinguishes the given from the new information and enables speakers to single out the clefted constituent in order to focus attention on it (Hedberg, 2000). Linguistic analyses suggest that the cleft-it copula clefted constituent-puts the clefted constituent into referential focus. Effectively, sentence (1) answers the question Who threw the snowball, putting emphasis on Harry as opposed to on any other individual; hence, the effect of clefting is referred to as contrastive focus (e.g., Rooth, 1992).It is already well established that linguistic focus leads to a privileged and deeper analysis of the focused term. For instance, the Moses illusion in form (2) is easily missed, whereas in (3) it is not (Bredart & Modolo, 1988):(2) Moses put two of each animal on the Ark, true or false? (3) It was Moses who put two of each animal on the Ark, true or false?The point of this illusion is that people do not usually notice that it was Noah, not Moses, who put the animals on the Ark. However, because the cleft construction in (3) causes a deeper analysis of the term Moses, detection of the anomaly is higher in this case. A variety of other studies have shown that focused elements are more easily processed at the discourse level. Cutler and Fodor (1979) manipulated contrastive focus through discourse context, presenting sentences such as (4) or (5) before the target sentence (6): (4) Which man was wearing the hat? (5) What hat was the man wearing? (6) The man on the corner was wearing the blue hat.Sentence (4) has the effect of putting The man on the corner into narrow focus, whereas (5) has the effect of putting the blue hat into narrow focus. Using a phoneme monitoring task, it was found that the phoneme detection latency was shorter for words in the scope of focus than for words outside of the scope of focus. Similar evidence of enhancement was found by Sturt, Sanford, Stewart, and University of Glasgow, Glasgow, ScotlandInformation structuring through the use of cleft sentences increases the processing efficiency of references to elements within the scope of focus. Furthermore, there is evidence t...

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