Effects of bonuses for punctuality on the tardiness of industrial workers

This study evaluated the effectiveness of an incentive procedure designed to increase the punctuality of six workers who were chronically late to work in a manufacturing company. The six workers in the experiment received a 2.00 pesos ($0.16 U.S.) bonus for every day that they arrived on time. A reversal design was used. The contingent bonuses increased the workers' rates of punctuality compared to their baseline rates. A control group of six workers observed during the same 77-week period showed a trend toward decreasing punctuality. These results suggest that the use of small daily bonuses is a practical procedure for modifying chronic tardiness among industrial workers.     

Dynamismus und atomismus-die beiden systeme der physik in der 1. H?lfte des 19. Jahrhunderts

Ohne ZusammenfassungVortrag beim Kolloquium Zur Struktur und Entwicklung naturwissenschaftlicher Theorien am 23. November 1975 in München.     

Recognition of positive and negative bandpass-filtered images

A study is reported in which the significance for vision of low- and high-spatial-frequency components of photographic positive and negative images was investigated by measuring recognition of bandpass-filtered photographs of faces. The results show that a 1.5 octave bandpass-filtered image contains sufficient visual information for good recognition performance, provided the filter is centred close to 20 cycles facewidth-1. At low spatial frequencies negatives are more difficult to recognize than positives, but at high spatial frequencies there is no difference in recognition, implying that it is the low-frequency components of negatives which present difficulties for the visual system.     

Lexical representation of fact and opinion

This research investigated the lexical properties underlying comprehension that a word represents fact or opinion. In Experiment 1 subjects reliably identified words as either fact or opinion. Bivariate correlations and multiple regression showed that fact/opinion judgments were predicted primarily by ratings of the ease of verifiability of a word's referent and secondarily by the word's literalness, but not by several other lexical attributes: abstractness-concreteness, vagueness-preciseness, and evaluation. Experiment 2 extended the results of the first experiment to an implicit fact/opinion judgment, i.e., the identification of headlines as originating from a newspaper's front page (presumably based primarily upon fact) or from the editorial page (presumably based upon opinion). The headline judgments, also made reliably by subjects, were predicted by the same variables found significant in the first experiment, i.e., by verifiability and literalness, but not by the other lexical properties. Thus, the results of both experiments indicate that the identification of a word as representing fact or opinion is rooted in a word's verifiability and literalness.     

Is there a role of depressive symptoms in the fear-avoidance model? A structural equation approach

The fear-avoidance (FA) model has gained widespread acceptance as a conceptual framework for investigating psychological factors such as FA beliefs and avoidance behavior, which contribute to chronic back pain and reduced functioning. Depressive symptoms are supposed to be related to FA beliefs and to foster avoidance behavior. This study aims to investigate the multivariate assumptions of the FA model with a focus on the role of depressive symptoms. A total of N = 360 patients with chronic nonspecific low back pain at admission of inpatient orthopedic rehabilitation participated in the survey. Measures included a numeric pain rating scale, Fear-Avoidance Beliefs Questionnaire, Pain Anxiety Symptoms Scale, Hannover Functional Ability Questionnaire and Patient Health Questionnaire. Using structural equation modeling (SEM), we construed a basic FA model and subsequently extended it by adding symptoms of depression as a covariate. The results of SEM indicated a good model fit for a basic FA model (χ²(263) = 431.069, p < .001, RMSEA = .042, CFI = .964, WRMR = .986). They confirmed the hypothesized relations and supported single mediations of the relationship between pain and functioning by FA beliefs and avoidance behavior. A second model including symptoms of depression as additional covariate (χ²(511) = 722.761, p < .001, RMSEA = .034, CFI = .956, WRMR = .949) showed a high impact of depressive symptoms on all FA model variables leading to a decrease of the FA mediations. The findings provide empirical support for the multivariate FA model and underline the importance of considering depressive symptoms in a multiple-target approach to understand the mechanisms of chronic pain.     

Tracking the speech signal – Time-locked MEG signals during perception of ultra-fast and moderately fast speech in blind and in sighted listeners

Blind people can learn to understand speech at ultra-high syllable rates (ca. 20 syllables/s), a capability associated with hemodynamic activation of the central-visual system. To further elucidate the neural mechanisms underlying this skill, magnetoencephalographic (MEG) measurements during listening to sentence utterances were cross-correlated with time courses derived from the speech signal (envelope, syllable onsets and pitch periodicity) to capture phase-locked MEG components (14 blind, 12 sighted subjects; speech rate = 8 or 16 syllables/s, pre-defined source regions: auditory and visual cortex, inferior frontal gyrus). Blind individuals showed stronger phase locking in auditory cortex than sighted controls, and right-hemisphere visual cortex activity correlated with syllable onsets in case of ultra-fast speech. Furthermore, inferior-frontal MEG components time-locked to pitch periodicity displayed opposite lateralization effects in sighted (towards right hemisphere) and blind subjects (left). Thus, ultra-fast speech comprehension in blind individuals appears associated with changes in early signal-related processing mechanisms both within and outside the central-auditory terrain.     

Visual search for size-defined target objects is modulated by the Ebbinghaus apparent-size illusion: facilitatory and inhibitory effects of the context objects

Five experiments were carried out to investigate under which conditions the apparent size of objects is computed and exploited optimally in visual search for size-defined targets. Observers searched for a target test circle that was retinally larger than the distractor test circles, with both types of circles surrounded by context circles modulating the apparent size of the test circles (Ebbinghaus illusion). RTs were the faster the better test circles could be differentiated from the context circles, ie with smaller numbers of context circles, larger distances, and higher lightness (or colour) contrast between test and context circles. Apparent-size modulation had a strong influence on search RTs, resulting in faster RTs with smaller, and slower RTs with larger, context circles. A model assuming overall facilitatory effects of the apparent-size modulation and interference effects arising from decreasing test-context circle discriminability can explain the present results.     

Cross-trial priming in visual search for singleton conjunction targets: role of repeated target and distractor features

Kristjánsson, Wang, and Nakayama (2002) demonstrated that visual search for conjunctively defined targets can be substantially expedited ("primed") when target and distractor features are repeated on consecutive trials. Two experiments were conducted to examine whether the search response time (RT) facilitation on target-present trials results from repetition of target-defining features, distractor features, or both. The experiments used a multiple conjunctive search paradigm (adapted from Kristjánsson et al., 2002), in which the target and distractor features were varied (i.e., repeated) independently of each other across successive trials. The RT facilitation was numerically largest when both target and distractor features were repeated, but not significantly larger than that when only distractor features were repeated. This indicates that cross-trial priming effects in conjunctive visual search result mainly from the repetition of distractor, rather than target, features.