invalid trial

See: mistrial
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80 ms) of valid and the mean reaction time of invalid trials (1166.
In order to analyze this in more detail, we performed post-hoc tests on valid and invalid trials for different valid trial ratios.
Results indicated that there was a 30 ms benefit of the valid trials when compared to the neutral trials, and there was a 39 ms cost of the invalid trials when compared to the neutral trials.
Twenty percent of the trials were invalid trials where the cue arrow incorrectly indicated the target location.
In both cases Jonides compared response times for valid trials (where the target appeared at the cued location) with response times for invalid trials (where the target appeared at an uncued location).
That is, clear differences between valid and invalid trials were observed with very brief (100ms) delays between cue and target.
In this paradigm, exogenous cues, displayed for under 150 ins, are placed in either the same location as an ensuing target on valid trials, or in the opposite location to a target on invalid trials.
The main effect of cue type reflected substantially faster reaction times for valid trials in comparison to invalid trials.
Moreover, if we admit that filtering could be facilitated in the valid trials, it would then be difficult to explain, by the same mechanism, why filtering would also be efficient in the invalid trials, when the object shape changes.
In endogenous orienting studies, the cue reliably points to the actual target location on valid trials, and signals the opposite target location on invalid trials.
More interesting, invalid trials produced a significant cost when the target was defined by an onset singleton.
Older participants may have decided that responses based on expectancies would potentially increase errors on invalid trials, therefore they sacrificed speed for accuracy by forming responses based upon the appearance of the target rather than in anticipation of the target.