invalid trial

See: mistrial
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An example of a valid and invalid trial is shown in Figure 2.
Facilitation refers to shorter reaction times to valid trials in comparison to invalid trials for short SOAs (0-300 ms SOA) while inhibition refers to longer reaction times to valid trials in comparison to invalid trials for longer SOAs (300-3000 ms).
Trials were labeled as "valid trials" or "invalid trials" depending on whether auditory stimuli did or did not correspond to the target locations.
For every different combination of the two independent variables, we calculated the mean reaction times and mean angular deviations of the hand movements for two trial groups: the trials where the auditory stimulus was associated with the target location (the "valid trials") and for the trials where the auditory stimulus was not associated with the target location (the "invalid trials").
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. A cue validity effect is said to occur when valid cues facilitate reaction times in comparison to invalid cues.
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. On neutral trials, either both locations or neither location are signalled.
Under conditions favoring automatic semantic activation (short prime-target interval, equal probability of valid and invalid trials), older adults have demonstrated semantic priming effects (faster responses to targets following valid primes than to targets following invalid primes) that were similar in magnitude to those of younger adults (Balota & Duchek, 1988; Burke, White, & Diaz, 1987; Chiarello, Church, & Hoyer, 1985; Ober, Shenaut, Jagust, & Stillman, 1991; but also see Bowles, 1994).