D.Reitter.JD.Moore/Joumal of Memory and Language 76(2014)29-6 35 odels of short-tes 1 PP is th cepted correlation between covariates 02:CP was resid ManTask Switchboard SE OR 0011 050 -0.176 084 (T 0.011 005 The speakers were told that their goal was pear to paint a different upposes ratio say whatever was necessa to compl te the task.It wa that s that an municative or situationl outcome If we accept this as All maps consisted of landmarks represented as line M5son.1989 priming levels vary at all with dialogue purpose.they tend task-rtd dialogue marked only on the giver's map.Landmarks ong th First.ifpr h s,4 onon the giv infuenced by dialogue purpos or contextual working (typically one per map pair)had diffe memory conter nts,then we .The seemore pri iction or ev dintecrori ce on 。e giver's ma sitio once a whole. The follower had only one repeated landmark.which was minrhhn twice as tailored their utterances to match the instruction giver e grammand syn room and half of the pairs could mak eeye contact.From tation in M his is contrary to what would be We pool the two datasets(Switchboard and Map Task) 0 will be the remainder of this paper. them ls ac or the experiments,except that the Disr covariate is now mea Like Switchboard.the Map Task is a corpus of spoke wo-person.th length differs). interlocutors work together to perform a task as quickly obtain the The IAM suggests that priming benefits speakers in con￾versation. At the same time, we observe that indepen￾dently fitted statistical models appear to paint a different picture of priming in spontaneous conversation, as opposed to priming in task-oriented dialogue. The test of the IAM we put forward presupposes ratio￾nality in cognitive processes, that is, that variation in an individual’s linguistic processes tends to optimize the com￾municative or situational outcome. If we accept this as a general principle (Anderson & Milson, 1989; Chater & Oaksford, 1999), then the IAM predicts that if speaker’s priming levels vary at all with dialogue purpose, they tend to vary such that task-oriented dialogue shows stronger priming than less goal-driven interaction, i.e., spontaneous conversation or small talk. Let us briefly consider the alternatives. First, if priming is the result of a mechanistic memory effect that is not influenced by dialogue purpose or contextual working memory contents, then we should not observe any differ￾ence in priming between the dialogue genres. Second, if we do find different priming levels, and we see more prim￾ing in spontaneous conversation, we would interpret this as a violation of the IAM prediction or even rationality as a whole. The differences in dialogue situation may have affected priming levels through a different mechanism than IAM. Speakers may have tailored their utterances to match the needs of their audience: In the experimental design that led to the Map Task data, participants were in the same room and half of the pairs could make eye contact. From an audience design perspective, the richer communication channel may have led them to reduce their levels of adap￾tation in Map Task. This is contrary to what would be expected under the IAM. Next, we describe the Map Task in detail. This corpus will be used throughout the remainder of this paper. The Map Task Like Switchboard, the Map Task is a corpus of spoken, two-person dialogues in English. Unlike Switchboard, the Map Task dialogues are task-oriented dialogues, in which interlocutors work together to perform a task as quickly and efficiently as possible. In each trial, the two speakers sat opposite one another and each had a map, which the other could not see. One of them, the instruction giver, had a map with a route drawn on it; the other participant, the instruction follower, had no route drawn on her map. The speakers were told that their goal was to reproduce the Instruction giver’s route on the Instruction follower’s map. The maps were not identical, and before they began the task the participants were told explicitly that their maps may differ in some respects, and that they could say whatever was necessary to complete the task. It was up to the participants to discover how the two maps dif￾fered (see Figs. 4 and 5). All maps consisted of landmarks represented as line drawings which are labelled with their intended name. All map routes began with a starting point, which was marked on both maps, and an end point, which was marked only on the giver’s map. Landmarks along the map alternated between those that appeared on both maps and those that appeared on only one map. For each map, 8 landmarks appeared on both maps, 4 on only the giver’s map, and 3 on only the follower’s map. In addition, some landmarks (typically one per map pair) had different names on the two maps. These names were identical in form and location but had different labels on the two maps (e.g., mill wheel vs. old mill). Finally, 2 landmarks appeared twice on the giver’s map, once in a position close to the route and once in a position more distant from the route. The follower had only one repeated landmark, which was distant. Each subject participated in four dialogues, twice as instruction giver and twice as instruction follower. The spoken interactions were recorded, transcribed and syn￾tactically annotated with phrase structure grammar.6 Method We pool the two datasets (Switchboard and Map Task), distinguishing them via a factor SOURCE. The methodology to quantify priming levels is the same as for the previous experiments, except that the DIST covariate is now mea￾sured in seconds instead of utterances (the notion of utter￾ance is not the same in each corpus, and average utterance length differs).7 Table 2 Two regression models of short-term rule repetition (Experiment 1). Prime-target distance in utterances. All continuous predictors were centred; CP was coded as 1, PP is the base case. Response variable (repetition probability), effect sizes (b) and standard errors (SE) in logits. Random effects of intercept and slope (distance), grouped by utterance. Maximum accepted correlation between covariates 0.2; CP was residualized. MapTask Switchboard Covariate b OR SE b OR SE Intercept 1:721 0.18 0:011⁄⁄⁄ 1:079 0.34 0:025⁄⁄⁄ lnðDistÞ 0:073 0.93 0:011⁄⁄⁄ 0:080 0.92 0:012⁄⁄⁄ lnðFreqÞ 0:722 2.06 0:01⁄⁄⁄ 0:884 2.42 0:006⁄⁄⁄ CP 0:684 0.50 0:013⁄⁄⁄ 0:176 0.84 0:011⁄⁄⁄ lnðDistÞ:CP 0:018 0.98 0:019 0:017 0.98 0:014 lnðDistÞ:lnðFreqÞ 0:043 1.04 0:011⁄⁄⁄ 0:057 1.06 0:006⁄⁄⁄ ⁄ p < 0.05. ⁄⁄⁄ p < 0.0001 (by jzj) . 6 Many other types of annotation are also available. See http:// www.hcrc.ed.ac.uk/maptask/ for a description and instructions of how to obtain the corpus. 7 Elsewhere, we have documented that time-based vs. utterance-based analysis does not confound the comparisons between the corpora Reitter (2008). D. Reitter, J.D. Moore / Journal of Memory and Language 76 (2014) 29–46 35