Claude G. Cech

Context Effects in Symbolic Magnitude Comparisons

Five experiments demonstrate that context has an effect on the ease with which people can determine the relative sizes of pairs of large and small animals. In a standard context, people are faster at choosing the larger of two large animals and the smaller of two small animals. However, when only pairs of small animals are presented (Experiment 1), relatively large pairs (RABBIT-BEAVER) are treated as if they were large animals and are discriminated more rapidly under the choose larger instruction. Similarly, when only large animals are presented (Experiment 2), the smaller of these are now treated as if they were small animals. Several models are presented that account for these effects of context, and these models are examined in subsequent experiments that impose yet other variations in magnitude pairings. The results demonstrate the importance of context in comparative judgement and place important constraints on theories of linear orders.

Message size constraints on discourse planning in synchronous computer-mediated communication

Three groups of 20 dyads planned the MTV Music Video Awards Show over computers. The groups varied in whether they could send 4-line, 10-line, or 18-line messages, in part to examine whether increased planning efficiency in computer-mediated communication reflects communication strategies associated with constraints on message size. The results demonstrate that increased efficiency is not a function of such design features as the maximum message that may be sent. However, the subjects in the 4-line condition sent shorter messages to one another, were less likely to engage in a strategy of making multiple suggestions that required a single assent, and were more likely to differ in the relative proportion of their contributions to the discourse. The subjects in the 10-line condition had shorter maximum messages (and proportionately more disfluencies) than did those in the 18-line condition, despite the finding that the maximum messages of the latter would have also fit within 10 lines. Thus, the results also support a claim that size of the text window may result in different discourse management strategies and may influence an initial discourse-planning stage.

Temporal properties of turn-taking and turn-packaging in synchronous computer-mediated communication

Turn structure and timing are examined in a variety of quasi-synchronous computer-mediated interfaces. The message window size, presence of scrolling, a single message window vs. message windows for each participant, and message persistence were systematically varied for pairs of interlocutors engaged in the same decision-making task. Participants produced more total words and more turns in conditions with larger windows and in those with scrolling, while separate windows conditioned even larger increases on these measures. Turn sizes were smaller in the latter conditions and response times were faster. In the persistent separate-window conditions, messages from the partner intervened before participants completed responses in over half of the messages.

The role of subtractions and comparisons in comparative judgments involving numerical reference points

Experiments in which subjects are asked to decide which of two digits is closer in magnitude to a third raise problems for many theories of linear orders. Holyoak (1978), for example, performed a number of these reference point experiments and concluded that they posed serious difficulties for a number of leading models. In their place, he offered the distance ratio model in which the ease of the decision in a reference point task is a function of the ratio of the distances between each stimulus and the reference point. In the present article, three experiments are presented that bear on the adequacy of Holyoaks position. In the first two studies, we present evidence that an important assumption of the distance ratio model is incorrect. In the third experiment, we compare the empirical adequacy of the distance ratio model with our own subtraction model. This model treats the reference point task as a concatenation of two subtractions and a simple digit comparison. This comparison operation is equivalent to the magnitude comparison required in standard linear order experiments. Overall, the subtraction model gives a somewhat better account than the distance ratio.

Categorization processes in mental comparisons.

Five experiments explore categorization and category-based congruity effects in mental comparisons. The first 4 experiments concentrate on categorization of infinite-set small items. The experiments vary the additional items presented and whether those items appear once (Experiments 1-2) or repeatedly (Experiments 3-4). Additional items include other small items (Experiment 1), relatively large items (Experiments 2-4), and items involving nonsize dimensions (Experiment 4). The critical small items show a complete congruity effect only in Experiments 1 and 3. Results suggest that categorization of infinite-set items may be based on range information alone (Experiment 1) but that multiple categorizations based on multiple ranges (Experiment 2) may require attentional effort. Results implicate categorization as a central process in mental comparison, despite differences in ease of categorization across paradigm.

Measuring Conformity to Discourse Routines in Decision-Making Interactions

In an effort to develop measures of discourse level management strategies, this study examines a measure of the degree to which decision-making interactions consist of sequences of utterance functions that are linked in a decision-making routine. The measure is applied to 100 dyadic interactions elicited in both face-to-face and computer-mediated environments with systematic variation of task complexity and message-window size. Every utterance in the interactions is coded according to a system that identifies decision-making functions and other routine functions of utterances. Markov analyses of the coded utterances make it possible to measure the relative frequencies with which sequences of 2 and 3 utterances trace a path in a Markov model of the decision routine. These proportions suggest that interactions in all conditions adhere to the model, although we find greater conformity in the computer-mediated environments, which is probably due to increased processing and attentional demands for greater efficiency. The results suggest that measures based on Markov analyses of coded interactions can provide useful measures for comparing discourse level properties, for correlating discourse features with other textual features, and for analyses of discourse management strategies.