Visual temporal integration for threshold,signal detectability,and reaction time measures

A comparison was made of temporal integration for three different response measures in a visual detection task: (1) response frequency, (2) signal detectability as measured for rating ROC curves. (3) simple reaction times (RTs). These measures were obtained on the same trials, to the same stimuli-orange (581 rim) light pulses of 50 min of visual angle fixated foveally and presented to dark-adapted Os in a monocular Maxwellian view. All three response measures showed a period of luminance-duration reciprocity (Bloch’s law), followed by a period of partial integration. The end points of luminance-duration reciprocity (critical duration) and partial integration (utilization time) were shorter for RTs than for the response frequency and signal detectability measures. Neurophysiological.implications of differences in time constants of integration for RT and psychophysical measures are discussed.     

Retrospective questions and correlations

In survey research it is not uncommon to ask questions of the following type: “How many times did you undertake actiona in reference periodT of length τ?.” The relationship is established between τ and the correlation of the number of reported actions with some background variable. To this end it is assumed that the process of actions satisfies a renewal model with individual heterogeneity. Also a model has to be formulated for possible recall effects. Applications are given in the field of medical consumption.     

The perceived tempi of coherent and streaming tone sequences

Previous research has demonstrated that a sequence of tones that is alternated between ears is stretched out in echoic memory, as compared with monaural sequences. Although the stimulus onset asynchronies (SOAs) were the same in the interaural and monaural conditions, the perceptual onset asynchronies (POAs) differed by 24 msec. The present study investigated whether an analogous perceptual phenomenon exists for frequency-alternating tone sequences. It turned out that the POAs of coherent and even of streaming tone sequences were precisely the same as with nonalternating tone sequences.     

The Concept Shifting Test: adult normative data

The Concept Shifting Test (CST) is a newly developed Trail Making Type test that measures concept shifting and executive functioning. The purpose of the present study was to determine whether CST performance was affected by age, gender, educational level, or handedness and to establish the normal range of test performance. The CST was administered to a large sample (N = 1,794) of cognitively intact adults (age range 24 to 81 years). The results showed that CST performance was superior in women, decreased with age, and increased with level of education. Handedness did not affect CST performance. Normative data that are corrected for the influences of these demographical variables were established with a regression-based normative approach.     

The Stroop color-word test: influence of age, sex, and education; and normative data for a large sample across the adult age range

The Stroop Color-Word Test was administered to 1,856 cognitively screened, healthy Dutch speaking participants aged 24 to 81 years. The effects of age, gender, and education on Stroop test performance were investigated to adequately stratify the normative data. The results showed that especially the speed-dependent Stroop scores (time to complete a subtest), rather than the accuracy measures (the errors made per Stroop sub-task), were profoundly affected by the demographic variables. In addition to the main effects of the demographic variables, an Age Low Level of Education interaction was found for the Error III and the Stroop Interference scores. This suggests that executive function, as measured by the Stroop test, declines with age and that the decline is more pronounced in people with a low level of education. This is consistent with the reserve hypothesis of brain aging (i.e., that education generates reserve capacity against the damaging effects of aging on brain functions). Normative Stroop data were established using both a regression-based and traditional approach, and the appropriateness of both methods for generating normative data is discussed.     

Relationships between physiological and psychological stress and salivary immunoglobulin A among young female gymnasts

We investigated whether psychological and physical stress induced by training or competition influence the secretory immune system among 12 highly trained young female gymnasts. Salivary levels of secretory IgA and cortisol responses to gymnastic training session or competition were assessed a total of 10 times, immediately before and after two training sessions which had different intensities and just before and after a major competition. These parameters were also measured on two non-training days. The Brunel Mood Scale was also used to assess the gymnasts's overall mood on each test day. IgA:Protein ratio was calculated. Significant decreases in this ratio were found after each exercise session, related to the physiological and psychological stress induced by exercise. Over the 5-mo. training period the presession IgA:Protein ratios were unchanged. Gymnasts registered any episodes of upper respiratory tract infection. Bouts of exercise induce transitory effects on the immune system in relation to the workload and the stress induced by the exercise without any relation to increased susceptibility to illness in children.     

The perceptual integration of auditory stimulus edges: an illusory short tone in stimulus patterns consisting of two partly overlapping glides

Two partly overlapping frequency glides can be perceived as consisting of a long pitch trajectory accompanied by a short tone in the temporal middle. It was found that the appearance of this middle tone could not be related to peripheral processes concerned with spectral splatter or combination tones that could have emerged during the overlap of the glides. Furthermore, it was found that the middle tone was perceived even when components of the 2 glides were separated by more than an equivalent rectangular bandwidth at any time during the overlap. The appearance of the middle tone indicates that auditory events can result from the perceptual integration of component parts-that is, stimulus edges-of acoustically different sounds.