Temporal integration of vibrotactile patterns

Self Cite

In a recent study, we measured temporal integration for vibrotactile spatial patterns presented to the fingertips. The patterns were generated on the tactile array of the Optaeon, a reading aid for the blind (Bliss, Katcher, Rogers, & Shepard, 1970;Craig, 1980). Several different tasks involving letter recognition were used in the study. In one task, letters were divided in half and the time between the presentation of the first and second half was varied, with the result that recognition performance declined as the time between the onset of letter halves increased. In a second task, the time between the onset of a letter and the onset of its complement, that portion of the tactile array not occupied by the letter, was varied. Letter recognition improved as the letter emerged from its complement (Craig, 1982). The results were similar to previous measures involving detection of vibratory stimuli in that the major portion of the integration took place within 50 to 100 msec of the onset of the first pattern (Gescheider, 1976;Green, 1976;Verrillo, 1965).The measurements with patterned stimuli and the temporal integration functions thus generated were similar to one another in that the skin showed complete temporal integration only over time periods of 10 msec and performance reached asymptotic levels as the time between stimuli approached 100 msec. There were, however, some differences in the functions produced by the several tasks, and it is the differences between functions that are the focus of this note.The task involving a letter and its complement produced sharper temporal integration functions, that is, performance reached asymptotic levels at briefer temporal separations than in the task in which letters were divided in half. The letter-complement task also turned out to be an easier task, in that levels of performance were higher than in the divided-letter task. The results suggested either that differences in the nature of the two tasks (such as ceiling effects) may have resulted in differences in the temporal integration functions or that the ease of discriminability of spatial patterns might produce differences in the functions, that is, patterns that

supporting

confidence: 76%

Vibratory temporal integration as a function of pattern discriminability

Craig

1984

Self Cite

“…However, even though tactile masking can be quite strong, tactile stimuli, like visual stimuli, seem to be more susceptible to backward masking than to forward masking (e.g., Craig, 1976Craig, , 1982aCraig, , 1982bKirman, 1986;Verrillo & Gescheider, 1979;Weisenberger & Craig, 1982). So it is unlikely that masking would play as strong a role as it did in these experiments.…”

Section: Discussionmentioning

confidence: 67%

Attentional limitations in processing sequentially presented vibrotactile targets

Hillstrom

Shapiro

Spence

2002

In seven experiments, participants experienced rapid, serially presented streams of vibrations and responded to specific targets in the streams. In visual (and sometimes auditory) streams presented in this manner, it is typical to find a deficit in reporting the second of two targets when both must be reported and the second appears within a short temporal interval of the first, but not when identical displays are presented but only the second target must be reported (e.g., the attentional blink, or AB). This conventional AB pattern was found in the last experiment, in which judgments were about target location. However in the first six experiments reported here, in which judgments were about frequency, intensity, duration, or location of targets, accuracy was dependent on target separation regardless of whether or not the first target was reported. This unconventional pattern could represent an AB if the first target was attended even when it was not reported. The evidence for this claim and an alternative possibility that location judgments are especially sensitive to attention manipulations are discussed.

“…Several experimental paradigms can be generated from the situation in which there are two patterns presented sequentially, and there are either one or two sites ofstimulation. The two patterns may be sequentially presented to the same site, and the subject required to combine them-a temporal integration task (Craig, 1982a(Craig, , 1984. The two patterns may be presented to separate sites, and the subject required to combine or compare the two patterns-a divided attention task (Craig, 1985).…”

Section: Indiana University Bloomington Indianamentioning

confidence: 99%

Vibrotactile masking: The role of response competition

Craig

1995

Self Cite

When two tactile patterns, a target and a nontarget pattern, are presented in dose temporal proximity to the same location, the nontarget pattern may interfere with the identification of the target. A series of experiments examined the extent to which the interference in target identification results from masking (interference in the representation of the target at an early stage of processing) or from response competition. A response competition view of pattern perception holds that both the target and nontarget are fully processed to the level of evoking responses. Interference is produced when subjects select the nontarget rather than the target. This view was tested with a paradigm developed in studies of selective attention. Pairs of tactile patterns were presented to subjects' left index fingerpads. The amount of interference produced by a nontarget that is physically different from a target depends on whether the nontarget is associated with the same response as the target or a different response. The amount of masking also depends on the set of target and nontarget patterns that are used. The results support the conclusion that subjects have available a representation of both the target and the nontarget and that a substantial portion of the interference previously attributed to masking may be due to response competition.