Predicting stress patterns in an unpredictable stress language: The use of non-lexical sources of evidence for stress assignment in Russian

The main goal of this research was to examine how readers of Russian assign stress to disyllabic words. In particular, we tested the claim that the process of stress assignment in Russian can only be accomplished lexically. Eleven potential non-lexical sources of evidence for stress in Russian were examined in regression and factorial studies. In Study 1, onset complexity, coda complexity, the orthography of the first syllable (CVC1), of the second syllable (CVC2), and of the ending of the second syllable (VC2) were found to be probabilistically associated with stress in Russian disyllables. In Studies 2 and 3, it was shown that Russian speakers do use 3 of these cues (CVC1, CVC2, and VC2) when making stress-assignment decisions. These results provide evidence against the idea that the nature of stress in the Russian language is so unpredictable that stress assignment can only be accomplished lexically. These results also suggest that any successful model of stress assignment in Russian needs to contain mechanisms allowing these 3 orthographic cues to play a role in the stress-assignment process.     

Avoidance of pain of unpredictable intensity

Unpredictability of the intensity of an aversive event might be an important factor in producing negative effects of the event, especially if the UCS becomes stronger than could have been expected. The present experiment tested the hypothesis that unpredictability of intensity of a painful stimulus contributes to avoidance behaviour. The experiment was concealed in a shock working-up procedure, which was done to assess the pain level subjects were willing to tolerate in a subsequent experiment. The experimental subjects, who received an unannounced sudden increase of the pain stimulus during the working-up procedure, tolerated less pain on a subjective as well as on an objective level (avoidance of high levels of pain) than the control subjects, who received the stimuli in a predictable pattern. The results support the hypothesis that unpredictability of intensity of an aversive event contributes to avoidance behaviour.     

Task switching under predictable and unpredictable circumstances

Task switching was examined under predictable and unpredictable circumstances. In the first two experiments (in predictable conditions), the upcoming task was determined by the trial sequence. In unpredictable conditions, this task was signaled by the stimulus. Under speeded conditions, participants had to judge either the parity of a digit or the vowel/consonant nature of a letter. On bivalent trials, a digit and a letter were presented. On univalent trials, a task-relevant character occurred alongside a task-irrelevant character (e.g., "&"). Task-switching costs were found, and response times were generally slower on bivalent than on univalent trials. This crosstalk effect was reduced when a task repetition was expected. In the final experiment, trial predictability was defined according to whether a task precue was presented prior to or concurrently with the trial stimulus. Contrasting patterns of crosstalk effects were obtained and are discussed in terms of exogenous and endogenous factors that affect task switching.     

Task-set reconfiguration with predictable and unpredictable task switches

Participants switched frequently between high/low and odd/even classification of a digit. The interval between a task cue and the next digit varied between blocks. In Experiment 1, the task switched predictably every two, four, or eight trials. In Experiment 2, switching predictably every four trials was compared with random switching. With predictable switching, the cost was limited to the first trial of a run. Random switching produced a more gradual approach to asymptotic performance. After one performance, control processes attenuate the resulting change in task-set bias if a further switch is likely, but this strategic modulation is soon overwhelmed by task-set priming through further performances. Preparation reduced switch costs but not interference from the irrelevant attribute: Control of interference appears to be reactive, not proactive. Switch costs did not increase with run length, suggesting that retrieval of the task set last associated with the stimulus did not contribute to switch costs.     

On how to be unpredictable: evidence from the voluntary task-switching paradigm

The voluntary task-switching paradigm requires subjects to select randomly between tasks and promises to provide a window into executive task selection independent of exogenous influences present in standard task-switching situations. We show here that the degree to which subjects perseverate on tasks across trials captures unique individual differences variance, but also that the switch rate is under strong stimulus-driven control: "Voluntary" switches are much more frequent when the stimulus changes than when it repeats. Most important, we show that individuals whose no-switch trials are selectively slowed exhibit less perseveration and stimulus-driven effects (and thus more voluntary selection) than individuals whose no-switch trials do not show this slowing. We suggest that selective slowing indicates a strategy of treating trials as discrete events--possibly through inhibition of the preceding task set. These results not only demonstrate massive nonvoluntary influences on voluntary selection that are largely untapped by standard task-switching measures, but also show how such influences can be counteracted through strategic adaptations.     

The effects of uncontrollable and unpredictable events on anagram solving

An experiment is reported which investigated the effects of uncontrollability and unpredictability in an anagram solving task. It was found that performance was disrupted following experience of outcomes which were uncontrollable or unpredictable or both. It was concluded that the effects of uncontrollability cannot be explained solely in terms of unpredictability.     

Predicting the Outcome of Treatment

The clinical question—“Which treatment(s) for which patients with what set of subgrouping characteristics working by what mechanism(s)?”—rests at the heart of differential therapeutics. Experimentally, this question reduces to a test of how well we can predict the outcome of treatment using the treatment conditions plus other moderating and mediating variables. Reflecting the discussions held at a recent National Institute of Mental Health (NIMH) conference on psychosocial treatments, and using pediatric anxiety disorders as a case in point, we discuss the problem of prediction in treatment outcome studies from the standpoint of definition of terms, using the general linear model of prediction. We also outline types of studies that may be useful in testing potential predictors, and put forward a possible matrix of predictor variables as currently implemented in an NIMH-funded treatment outcome study of pediatric obsessive-compulsive disorder (OCD). We conclude by making specific suggestions for implementing a broader approach to the study of predictors.     

Predicting Protest

We develop and test a model of participation in protest activities. Data were collected from 182 students in the week preceding and the week following a provincial day of protest against escalating tuition rates. Militancy predicted intent to participate, as did the perceived instrumentality of participation. Intent predicted actual participation and mediated the effects of instrumentality and militancy on participation. As hypothesized, participation in the protest predicted postprotest loyalty and militancy. Implications for further research on social protest and labor union strikes are discussed.