A computer program for Spearman-K?rber and probit analysis of psychometric function data.

PMETRIC is a computer program for the analysis of observed psychometric functions. It can estimate the parameters of these functions, using either probit analysis (a parametric technique) or the Spearman-K?rber method (a nonparametric one). For probit analysis, either a maximum likelihood or a minimum chi 2 criterion may be used for parameter estimation. In addition, standard errors of parameter estimates can be estimated via bootstrapping. The program can be used to analyze data obtained from either yes-no or m-alternative forced-choice tasks. To facilitate the use of PMETRIC in simulation work, an associated program, PMETGEN, is provided for the generation of simulated psychometric function data. Use of PMETRIC is illustrated with data from a duration discrimination task.     

The effect of a cross-trial shift of auditory warning signals on the sequential foreperiod effect

When a warning signal (WS) precedes an imperative signal (IS) by a certain amount of time (the foreperiod, FP), responses are speeded. Moreover, this effect is modulated by the FP length in the previous trial. This sequential FP effect has lately been attributed to a trace-conditioning mechanism according to which individuals learn (and re-learn) temporal relationships between the WS and the IS. Recent evidence suggests that sensory WS attributes are critical to trigger time-related response activation. Specifically, when WS modality is shifted in subsequent trials (e.g., from auditory to visual modality), the sequential FP effect becomes attenuated. This study examined whether the sequential FP effect is reduced only by between-modality shifts or whether this attenuation generalizes to cross-trial shifts of WS attributes within modalities. We compared dimensional (low vs. high tone frequency) and qualitative shifts (pure tone vs. noise) of equal-intense auditory WS events. The results of four experiments revealed that shifts of tone frequency did not, whereas shifts of qualitative tone characteristics did attenuate the sequential FP effect. These results support the view that the WS acts as a trigger cue that unintentionally activates responses at previously reinforced critical moments.     

Left–right coding of past and future in language: The mental timeline during sentence processing

The metaphoric mapping theory suggests that abstract concepts, like time, are represented in terms of concrete dimensions such as space. This theory receives support from several lines of research ranging from psychophysics to linguistics and cultural studies; especially strong support comes from recent response time studies. These studies have reported congruency effects between the dimensions of time and space indicating that time evokes spatial representations that may facilitate or impede responses to words with a temporal connotation. The present paper reports the results of three linguistic experiments that examined this congruency effect when participants processed past- and future-related sentences. Response time was shorter when past-related sentences required a left-hand response and future-related sentences a right-hand response than when this mapping of time onto response hand was reversed (Experiment 1). This result suggests that participants can form time–space associations during the processing of sentences and thus this result is consistent with the view that time is mentally represented from left to right. The activation of these time–space associations, however, appears to be non-automatic as shown by the results of Experiments 2 and 3 when participants were asked to perform a non-temporal meaning discrimination task.     

Why untrained control groups provide invalid baselines: A reply to Dienes and Altmann

Dienes and Altmann argue that an untrained control group provides a reliable baseline to measure artificial grammar learning. In this reply, we first provide a fictitious example to demonstrate that this assessment is faulty. We then analyse why this assessment is wrong, and we reiterate the solution proposed in Reber and Perruchet (this issue) for a proper control. Finally, we point out the importance of these methodological principles in the context of implicit learning studies.     

Does Immediate Arousal Enhance Response Force in Simple Reaction Time?

Three experiments assessed the hypothesis that immediate arousal enhances response force in speeded reaction-time tasks. Immediate arousal was manipulated via the physical characteristics of a warning signal that closely preceded the imperative response signal. The first experiment revealed that responses were more forceful and faster for a loud than for a soft warning signal. The second experiment manipulated the duration of an auditory warning signal; more forceful but slower responses were obtained for longer durations of the warning signal. The third experiment employed a visual warning signal, and its intensity was either rather weak or moderately bright; more forceful responses and slightly faster responses were observed for the brighter warning signal. Although the results of Experiment 1 and 2 may agree with an arousal account, the findings of Experiment 3 argue against such an account. A stimulus-response compatibility hypothesis is suggested as one possible alternative account.