Simultaneous bilateral testing: validation of a new protocol to detect insincere effort during grip and pinch strength testing.

The detection of feigned weakness in hand grip strength assessment is difficult. The authors review several proposed methods and their weaknesses. A comparison of unilateral testing and simultaneous bilateral testing with the Jamar dynamometer and the Baseline pinch gauge is demonstrated as a solution. An experiment involved 100 asymptomatic subjects who were tested twice, once under instructions to give a full effort and once under instructions to feign weakness. Seven statistical criteria of noncompliance were chosen. Defining noncompliance as failing two or more of the seven criteria, 99% of the instructed noncompliant subjects were correctly classified as noncompliant. No subjects were incorrectly classified as noncompliant during instructed compliant testing. Twelve subjects failed on a single criterion. On retesting, all but one were correctly classified. One subject in the instructed noncompliant group passed all criteria. Accuracy was 99.5%, including retesting of the 12 "gray-zone" subjects.

Observations on the microstructure of response conflict.

Three experiments are detailed which indicate the usefulness of the frequency of double responses (DRs) as an indicant of response conflict, in addition to the usual RT measures. DRs are responses on which an initial (often partial) error response is made that is rapidly amended to a correct response. Such responses occur most frequently in stimulus conditions where response conflict is expected by theory to be present and is indicated by changes in RT. Partial activation of competing responses has been demonstrated before using physiological measures (Coles, Gratton, Bashore, C. W. Eriksen, & Donchin, 1985; C. W. Eriksen, Coles, Morris, & O'Hara, 1985) when both responses could physically be made at the same time. DRs seem to be an equivalent type of movement when the subject cannot physically make but one movement at a time. The usefulness of this index of response conflict lies in its ease of implementation.

Processing redundant signals: coactivation, divided attention, or what?

The evidence for and against a redundancy gain in reaction time (RT) when the target is repeated in the visual display is reviewed. We consider the relevance of redundancy gains under these circumstances to the question of whether attention can be simultaneously directed to separate locations in the visual field. In the present experiments, two capital letters were the target stimuli in a two-alternative forced-choice RT paradigm. In addition to the usual conditions of single-target trials, trials on which the target is repeated in the display, and trials on which the target occurs with a noise letter, we introduced the innovation of a condition in which both targets occur in the display. In our two experiments, RT was fastest with single-target displays and slowest with displays containing a target and a noise letter. There was no significant difference in RT to displays in which the target was repeated and displays in which both targets were presented. Both conditions showed a redundancy gain when compared with displays containing a target and a noise letter. The lack of response competition in the both-targets condition and the overall pattern of the results were well explained by a unitary attentional focus that serially processed the letters in the display. Analyses of minima and maxima RTs were consistent with this interpretation.

Effects of tasks interpolated during rest on reminiscence for pursuit-rotor performance and inverted-alphabet printing: a test of a consolidation theory of reminiscence.

As a test of a consolidation theory of reminiscence, 150 female college students practiced inverted-alphabet printing and the pursuit rotor for 5 min., rested for 20 min., and then practiced for 2 more min. During the rest period, some subjects rested while others performed reverse-cue rotary pursuit or mirror tracing. No reduction in reminiscence produced by tasks occurring during the rest period was found. While the failure to support a consolidation theory of reminiscence could not be explained, the possibility of sex differences in response to tasks occurring during the rest period was discussed.