Typicality and novelty have often been shown to be related to aesthetic preference of human artefacts. Since a typical product is rarely new and, conversely, a novel product will not often be designated as typical, the positive effects of both features seem incompatible. In three studies it was shown that typicality (operationalized as 'goodness of example') and novelty are jointly and equally effective in explaining the aesthetic preference of consumer products, but that they suppress each other's effect. Direct correlations between both variables and aesthetic preference were not significant, but each relationship became highly significant when the influence of the other variable was partialed out. In Study 2, it was furthermore demonstrated that the expertise level of observers did not affect the relative contribution of novelty and typicality. It was finally shown (Study 3) that a more 'objective' measure of typicality, central tendency - operationalized as an exemplar's average similarity to all other members of the category - yielded the same effect of typicality on aesthetic preference. In sum, all three studies showed that people prefer novel designs as long as the novelty does not affect typicality, or, phrased differently, they prefer typicality given that this is not to the detriment of novelty. Preferred are products with an optimal combination of both aspects.

Comparison of initial and terminal temporal accuracy of 5 male top table tennis players performing attacking forehand drives led to the conclusion that because of a higher temporal accuracy at the moment of ball/bat contact than at initiation the players did not fully rely on a consistent movement production strategy. Functional trial-to-trial variation was evidenced by negative correlations between the perceptually specified time-to-contact at the moment of initiation and the mean acceleration during the drive; within-trial adaptation was also evident for two of the Ss. It is argued that task constraints provide the organizing principles for perception and action at the same time, thereby establishing a mutual dependency between the two. Allowing for changes in these parameters over time, a unified explanation is suggested that does not take recourse to large amounts of (tacit) knowledge on the part of the S.

The results suggest that acoustically paced treadmill walking provides an effective means for immediately modifying stride frequency and improving gait coordination in people after stroke and, therefore, may be usefully applied in physical therapist practice. Future research directions for developing guidelines for using acoustically paced treadmill walking in physical therapist practice are discussed.

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Background and Purpose. The Performance-Oriented Mobility Assessment (POMA) is a widely used instrument that provides an evaluation of balance and gait. It is used clinically to determine the mobility status of older adults or to evaluate changes over time. To support the use of the POMA for these purposes, the clinimetric properties (in particular, responsiveness) were determined. Subjects. Participants (78% female; mean age=84.9 years) were living in either self-care or nursing-care residences. Concurrent and discriminant validity were assessed with the total group (N=245), whereas reliability and responsiveness were determined with a subsample (n=30). Fall-related predictive validity was assessed with a subsample of 72 participants. Methods. In addition to the POMA, several reference performance tests were administered. The POMA was assessed on 2 consecutive days by 2 raters (observers). The analyses included the calculation of Spearman rank correlation coefficients (R), limits of agreement (LOA) with Bland-Altman plots, minimal detectable changes at the 95% confidence level (MDC95), and sensitivity and specificity with regard to predicting falls. When possible, findings for the total scale (POMA-T) were complemented by findings for its balance subscale (POMA-B) and its gait subscale (POMA-G). Results. The interrater and test-retest reliability for the POMA-T and the POMA-B were good (R=.74–.93), whereas for the POMA-G, the reliability values, although high as well, were systematically slightly lower (R=.72–.89). The Spearman correlations with the reference performance tests (R=|.64|–|.68|) indicated satisfactory concurrent validity for the POMA-T and the POMA-B, but the corresponding findings for the POMA-G (R=|.52|–|.56|) were less convincing. The discriminant validity values of the 3 scales were about the same. The LOA for the POMA-T were on the order of –4.0 to 4.0 for test-retest agreement and –3.0 to 3.0 for interrater agreement. On the basis of the MDC95 values, it was concluded that changes in POMA-T scores at the individual level should be at least 5 points and that those at the group level (n=30) should be at least 0.8 point to be considered reliable. Even when optimal cutoff points were used, sensitivity and specificity values (varying between 62.5% and 66.1%) for the POMA-T as well as for its 2 subscales indicated poor accuracy in predicting falls. Discussion and Conclusion. The POMA-T and its subscale POMA-B have adequate reliability and validity for assessing mobility in older adults. The POMA-T is useful for demonstrating intervention effects at the group level. Changes within subjects, however, should be at least 5 points before being interpreted as reliable changes. The accuracy of the POMA-T in predicting falls is poor.