Response competition effects insame-different judgments

An account ofsame-different discriminations that is based upon a continuous-flow model of visual information processing (C. W. Eriksen & Schultz, 1979) and response competition and inhibition between the responses by which the subject signifies his judgment is presented. We show that a response signifyingsame will on the average be executed faster due to less priming or incipient activation of the competing response,different. In the experiment, the subjects matched letters on the basis of physical identity. The degree of priming ofdifferent responses on same trials and ofsame responses ondifferent trials was manipulated by an extraneous noise letter placed in the display. Latency for judgments onsame trials increased as the feature overlap of noise and target letters decreased. Latencies were shorter ondifferent trials when the noise letter was dissimilar to either target letter than when the noise letter was the same as one of the targets. These results were consistent with the response-competition interpretation.     

Ursachen der gegenseitigen Verdeckung von taktil dargebotenen Buchstaben: Unterbrechung,Summation oder Verzögerung?

Zusammenfassung Für die Erklärung der Verdeckung von Reizen in verschiedenen Sinnesmodalitäten mit einfacher Struktur wurden in der Literature bisher im wesentlichen zwei verschiedene Erklärungskonzepte diskutiert: Die Summationshypotheses behauptet, daß die Eindrücke von schnell aufeinanderfolgenden Reizen sich zu einer Gesamtrepräsentation überlagern, aus der die Einzelreize erschwert herauszuanalysieren sind, die Unterbrechungshypothese dagegen nimmt an, daß die Verdeckung auf eine Störung der Verarbeitung des einen Reizes durch die kurzzeitig folgende Darbietung eines weiteren Reizes zurückgeht. Zur Erklärung der gegenseitigen Verdeckung von taktil dargebotenen Buchstaben sind beide Hypothesen ungeeignet, weil sie die unterschiedliche Beeinträchtigung von Form- und Positionserkennung der Buchstaben nicht erfassen können. Deshalb wurde eine neue Hypothese aufgestellt: Die Repräsentation eines Reizes im sensorischen Register wird durch die Merkmalsanalyse des vorangegangenen Reizes kaum behindert, aber dessen Übertragung aus dem analysierenden System in das Kurzzeitgedächtnis eine bestimmte Zeit verzögert. Diese Verzögerungshypothese wurde mit einem Experiment überprüft, in dem 3 Vpn je etwa 12 Versuchsstunden lang die Erkennung von Buchstabenpaaren übten. Da die Diskrimination zwischen den Buchstaben bei taktiler Darbietung sehr viel schwieriger als bei visueller ist, wurden nur 5 Buchstaben im Experiment verwendet. Die Ergebnisse des Experiments werden durch ein mathematisches Modell beschrieben. Bezüglich der numerischen Werte der freien Parameter machen die 3 Hypothesen unterschiedliche Vorhersagen. Die Parameterschätzung ergab eine gute Übereinstimmung des Modells mit den Daten und zeigte eine Überlegenheit des Konzeptes Verzögerung für die Erklärung der gegenseitigen Verdeckung taktil dargebotener Buchstaben.

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Sources of mutual masking of tactile presented letters: Interruption, summation or delay?

Summary Two different explanations of the masking phenomenon with simple structured stimuli have been discussed in the literature: The summation hypothesis and the interruption hypothesis. The summation hypothesis maintains that the images of quickly succeeding stimuli superimpose and build up one unified representation from which the single stimuli are difficult to analyse. In contrast the interruption hypothesis assumes that masking is caused by the successive stimulus disturbing the processing of its predecessor. Both hypotheses are unacceptable for an explanation of the mutual masking of tactile presented letters where a different impairment of form and position recognition is observed. Therefore a third hypothesis was tried: The processing of a preceding stimulus hardly affects the representation of the successive one in the sensory register. Rather the transfer from the analysing system to short-term memory is delayed by a certain time. This delay hypothesis was tested by an experiment in which three subjects practiced to recognize pairs of letters for a total of 12 sessions. Since discrimination between letters is much more difficult with tactile compared to visual presentation only five letters were used as stimuli. The results are described by a mathematical model. The three hypotheses predict discrepant numerical values for the free parameters. Parameter estimation revealed a close fit between the general model and the data and showed a superiority of the delay hypothesis as an explanation of mutual masking of tactile presented stimuli.

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Für die wertvolle Beratung bei der Erstellung des endgültigen Textes danken wir besonders Herrn Professor Dr. K. F. Wender und Herr Dr. K. Nippert.     

Launching the effect: Representations of causal movements are influenced by what they lead to

We investigated whether the representation of an observed causal movement is influenced by its observed effect. Subjects watched displays showing collisions between two objects. In this 'launching event' (Michotte, 1946/1963), one of the two objects (Object A) started to move and set a second, initially stationary, object (Object B) into motion, which gave a strong impression of apparent causality. The apparent effectiveness of A's movement was manipulated by varying the velocities of A and B. When the velocity of B was higher than that of A, the effectiveness of the collision was high; when it was smaller it was low. Then, subjects were asked to reproduce the velocity of the causal movement. Reproduced velocity followed the velocity of both Object A and Object B, which supports the hypothesis that the effect of a movement is integrated with its apparent cause. However, when apparent causality was reduced by changing the direction of motion of B or by covering the point of collision, the influence of the effect on the representation of the cause persisted, suggesting that retroactive interference may account for the findings. The interference effect could not be reduced to temporal recency or spatial integration and was not obtained in the reverse temporal order (proactive interference). Rather, the two successive movements were blended in memory.     

Interactive effects of social network centrality and social identification on stress

The present study aimed to integrate the social identity approach to health and well-being with social network analysis. Previous research on the effects of social network centrality on stress has yielded mixed results. Building on the social identity approach, we argued that these mixed results can be explained, in part, by taking into account the degree to which individuals identify with the social network. We hence hypothesized that the effects of social network centrality on stress are moderated by social identification. Using a full roster method, we assessed the social network of first-year psychology students right after the start of their study programme and three months later. The effects of network centrality (betweenness, closeness, eigenvector centrality) and social identification on stress were examined using structural equation models. As predicted, our results revealed a significant interaction between network centrality and social identification on stress: For weakly or moderately identified students, network centrality was positively related to stress. By contrast, for strongly identified students, network centrality was unrelated to stress. In conclusion, our results point to the perils of being well-connected yet not feeling like one belongs to a group.     

Is identity illusory?

Certain of our traits are thought more central to who we are: they comprise our individual identity. What makes these traits privileged in this way? What accounts for their identity centrality? Although considerations of identity play a key role in many different areas of moral philosophy, I argue that we currently have no satisfactory account of the basis of identity centrality. Nor should we expect one. Rather, we should adopt an error theory: we should concede that there is nothing in reality corresponding to the perceived distinction between the central and peripheral traits of a person.     

Moderating Loss Aversion: Loss Aversion Has Moderators,But Reports of its Death are Greatly Exaggerated

Loss aversion, the principle that losses impact decision making more than equivalent gains, is a fundamental idea in consumer behavior and decision making, though its existence has recently been called into question. Across five unique samples (N_total = 17,720), we tested several moderators of loss aversion, which supported a preference construction account. Across studies, more domain knowledge and experience were associated with lower loss aversion, though people of all knowledge and experience levels were loss averse. Among car buyers, those who knew more about a particular car attribute (e.g., fuel economy) were less loss averse for that attribute but not other attributes (e.g., comfort), consistent with the idea that people with less attribute knowledge are more likely to construct preferences, thereby increasing loss aversion. Additionally, older consumers were more loss averse across different loss aversion measures and studies. We discuss implications for several accounts of loss aversion, including accounts rooted in status quo bias, emotion, or ownership. In addition to discovering loss aversion moderators, we cast doubt on recent claims that loss aversion is a fallacy or is fully explained by status quo bias, risk aversion, or the educated laboratory samples often used to study loss aversion.     

Teacher’s use of praise,clarity of school rules and classroom climate: comparing classroom compositions in terms of disruptive students

Clarity of school rules and teachers’ use of praise are strategies suggested to facilitate a positive classroom climate. Studies indicate difficulties for teachers to use such approaches in classrooms with higher levels of disruption. To study (1) if student-rated clarity of school rules, use of praise, and classroom climate differ between students in classes with lower numbers of disruptive students versus classes with higher numbers, (2) if clarity of school rules and teacher’s use of praise are longitudinally associated with classroom climate, (3) if the possible longitudinal association differs between groups, classes (n = 109) in school grades 5–7 were divided into two groups, based on head teacher ratings of disruptive students in class. Baseline and 12-month follow-up responses collected within a Swedish trial were used to perform multiple regression analysis, to compare groups and to investigate possible longitudinal associations. Students in classes with less disruption rated all variables more positively. Classroom climate deteriorated over time in both groups, even if the low disruption group perceived their climate as more positive at follow up. Clarity of school rules did not substantially contribute to classroom climate longitudinally, whereas teacher’s use of praise to some extent did. The difference in longitudinal associations between groups was marginal, hence our hypothesis on weaker associations in the high disruption group could not be confirmed. Clarity of school rules is not longitudinally associated with classroom climate, but teachers may positively influence the learning environment by giving praise, regardless of level of disruption.     

Opposing effects of phonological similarity on item and order memory of words and nonwords in the serial recall task

This study shows that the classical phonological similarity effect (PSE) in immediate serial recall is critically affected by the lexicality of list items, the type of phonological similarity involved, and the scoring procedure. PSE was present in the serial recall score when phonologically distinct words were compared to words that share the middle vowel and end consonant (rhyming lists). PSE was absent in the serial recall score when phonologically distinct words were compared to words that share the initial and final consonants (consonant frame lists). There was a reversal of PSE in serial recall of nonwords when comparing distinct lists to both types of similar lists. Recall accuracy on the other hand was higher for distinct lists regardless of lexicality. Item errors dominated in relation to order errors in the case of nonwords, whereas order errors dominated in relation to item errors in the case of words. Furthermore, order errors were more common for phonologically similar lists, whereas item errors were more common for phonologically distinct lists. This may be the result of intra-list and inter-list interference, respectively. The dominance of the former error type may cause a classical PSE, whereas the dominance of the latter error type may cause a reversal of PSE. Finally, an item identification task yielded no evidence of an association between intra-list interference and discriminability of items in a list.     

Short and long-term motor skill learning in an accelerated rotarod training paradigm

Rodent models of motor skill learning include skilled forelimb reaching and acrobatic locomotor paradigms. This study characterizes motor skill learning in the accelerated rotarod task. Thirty Long-Evans rats (300-400 g) were trained on an accelerated rotarod (1cm/s(2)) over eight consecutive sessions (=days, 20 trials each). Improvement in rotarod velocities mastered before falling off the rod was observed within and between sessions (plateau after five sessions). Intrasession improvement was incompletely retained at the beginning of the next day's session. Over several training sessions, intrasession improvement diminished, suggesting a ceiling effect. After 1 week of pause, the rotarod skill was retained. Locomotor exercise in a running wheel for 30 min before the first rotarod session did not affect intrasession improvement. Running-wheel exposure for 6 days did not diminish the rate of rotarod skill learning (steepness of the learning curve) but improved overall performance (upward shift of curve). Video analysis of gait on the rotarod showed that rats developed a motor strategy by modifying their gait patterns during training. The data demonstrate that rotarod improvement is not the result of enhanced general locomotor ability or fitness, which are trained in the running wheel, but requires a change in the motor strategy to master the task. Accelerated rotarod training can be regarded a valid paradigm for motor skill learning over short (intrasession, minutes) and long time frames (intersession, days).     

Predictive pointing movements and saccades toward a moving target

The authors investigated whether and, if so, how velocity information is used to control predictive manual pointing movements and saccades. Participants (N = 6) intercepted an occluded moving target as if it were still visible. They kept their eyes fixated while the target moved. The target traveled over a fixed distance and changed its velocity on the way. The presentation time of the final velocity was varied. Both the eye and the hand overshot the slow target and undershot the fast target, particularly when the duration of the final velocity was short. Thus, responses were biased in the direction of the target's initial velocity. The error seemed to arise because participants did not take their latency into account when aiming at the target. Instead, they strategically aimed farther ahead when the target was fast. Amplitude was also more related to the position of velocity change than to final velocity duration. Both findings suggest that target velocity is not extrapolated but that individuals add an increment to the position of velocity change.