On the dimensionality of the System Usability Scale: a test of alternative measurement models

The System Usability Scale (SUS), developed by Brooke (Usability evaluation in industry, Taylor & Francis, London, pp 189–194, 1996), had a great success among usability practitioners since it is a quick and easy to use measure for collecting users’ usability evaluation of a system. Recently, Lewis and Sauro (Proceedings of the human computer interaction international conference (HCII 2009), San Diego CA, USA, 2009) have proposed a two-factor structure—Usability (8 items) and Learnability (2 items)—suggesting that practitioners might take advantage of these new factors to extract additional information from SUS data. In order to verify the dimensionality in the SUS’ two-component structure, we estimated the parameters and tested with a structural equation model the SUS structure on a sample of 196 university users. Our data indicated that both the unidimensional model and the two-factor model with uncorrelated factors proposed by Lewis and Sauro (Proceedings of the human computer interaction international conference (HCII 2009), San Diego CA, USA, 2009) had a not satisfactory fit to the data. We thus released the hypothesis that Usability and Learnability are independent components of SUS ratings and tested a less restrictive model with correlated factors. This model not only yielded a good fit to the data, but it was also significantly more appropriate to represent the structure of SUS ratings.

Using the self to change implicit attitudes

Implicit attitudes are automatic evaluations that occur upon encountering an object. Pairing a particular object with one's self should lead to a positive implicit evaluation of that object as, on the whole, people evaluate themselves positively. Study 1 (N = 83) demonstrated that asking participants to associate themselves with a particular drink (A) and others with an alternative drink (B) was enough to enhance implicit preference for drink A over drink B indexed by scores on the Implicit Association Test (IAT). Two further studies were conducted to rule out the possibility that the effects of the manipulation were restricted to the procedure and measures adopted in Study 1. Study 2 (N = 81) tested the mechanism underlying the effects of the manipulation. The results suggested that the change in implicit attitudes towards the drinks varied as a function of the level of one's self‐esteem. Specifically, associating one's self with drink A led to more favourable implicit attitudes towards drink A particularly when one's self was evaluated more positively. In the third study (N = 44), the basic effect of the manipulation was replicated in an alternative measure of implicit attitudes (the Affect Misattribution Procedure). In all three studies, the effects were unique to implicit measures and did not generalize to explicit measures. Copyright © 2009 John Wiley & Sons, Ltd.     

Individual Differences in Risky Decision Making: A Meta‐analysis of Sensation Seeking and Impulsivity with the Balloon Analogue Risk Task

To represent the state‐of‐the‐art in an effort to understand the relation between personality and risk taking, we selected a popular decision task with characteristics that parallel risk taking in the real world and two personality traits commonly believed to influence risk taking. A meta‐analysis is presented based on 22 studies of the Balloon Analogue Risk Task from which correlations with sensation seeking and impulsivity assessments could be obtained. Results calculated on a total of 2120 participants showed that effect size for the relation of sensation seeking with risk taking was in the small–moderate range ( = .14), whereas the effect size for impulsivity was just around the small effect size threshold ( = .10). Although we considered participants' demographics as moderators, we found only significantly larger effect sizes for the older adolescents and young adults compared with other ages. The findings of the present review supported the view that inconsistencies in personality–risk research were mostly due to random fluctuations of specific effect sizes, rather than to lack of theoretical ties or to measurement unreliability. It is also concluded that studies aimed at relating individual differences in personality to performance in experimental decision tasks need an appropriate sample size to achieve the power to produce significant results. Copyright © 2013 John Wiley & Sons, Ltd.     

Implicit affective evaluation of visual symmetry

Symmetry and beauty are strongly linked, but is the positive response to visual symmetry automatic? We used the Implicit Association Test (IAT) to measure the valence of visual regularities in the absence of overt judgments. In our first experiment, participants classified dot patterns as random or having an axis of reflection, and words as positive or negative. When the same button was used to report reflection and positive words, responses were faster than when the same button was used to report reflection and negative words. We take this association to indicate an implicit preference for reflectional patterns. In subsequent experiments, a reflected pattern was preferred to a rotation or translation, and a rotational pattern was preferred to random patterns. In some cases these results were not in agreement with verbally reported preferences, but implicit preferences were always predicted by the speed at which patterns could be identified. We conclude that the IAT can unearth an automatic affective response produced by perceptual fluency. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

The perceived structural shape of thin (wire-like) objects is different from that of silhouettes

Observers are faster at judging the position of convex vertices compared to concave vertices. This is believed to be due to an explicit representation of position for visual parts. The best evidence comes from comparing the same contours perceived as either figures or holes, because this is a pure figure ground reversal (Bertamini and Croucher, 2003 Cognition 87 33 - 54; Bertamini and Mosca, 2004 Perception 33 35-48). Specifically, an interaction is present between type of object (object or hole) and shape. One assumption is that the contour of a silhouette is perceived as the rim of a solid object. It follows that a different pattern should be found for thin (wire-like) objects compared to silhouettes. We confirm this difference in three experiments. We argue that this is due to the perceived parts when contours can be interpreted as self-occlusion rims.     

Acquisition, retention, and recall of memory after injection of RS67333, a 5-HT(4) receptor agonist, into the nucleus basalis magnocellularis of the rat

The serotonin 5-HT4 subtype receptor is predominantly localized into anatomical structures linked to memory and cognition. A few experimental studies report that the acute systemic administration of selective 5-HT4 agonists has ameliorative effects on memory performance, and that these effects are reversed by contemporary administration of 5-HT4 receptor antagonists. To verify whether this procognitive action occurs via the activation of the cholinergic nucleus basalis magnocellularis (NBM)-cortical pathways, we examined the effects of RS67333, a selective partial agonist of the 5-HT4 receptor, on rat performance in a place recognition task upon local administration of the drug into the NBM area. The intra-NBM administration of RS67333 enhances the acquisition (200-500 ng/0.5 microL) and the consolidation (40-200 ng/0.5 microL) of the place recognition memory. These effects are reversed by pretreatment with the selective 5-HT4 receptor antagonist RS39604 (300 ng/0.5 microL). Conversely, the recall of memory is not affected by the 5-HT4 agonist. Our results indicate that 5-HT4 receptors located within the NBM may play a role in spatial memory and that the procognitive effect of RS67333 is due, at least in part, to the potentiation of the activity of cholinergic NBM-cortical pathways.     

Automatic spatial coding of perceived gaze direction is revealed by the Simon effect

In a typical Simon task, the (irrelevant) spatial position of the stimulus interferes with the processing of the salient characteristic (e.g., color). We used the Simon effect to investigate the automatic processing of gaze cues. We show that a simple drawing of schematic eyes automatically generates a spatially defined code of gaze direction. Although completely irrelevant to the task, direction of gaze influenced reaction times in a spatially selective two-choice discrimination based on eye color. Moreover, in one experiment employing an orthogonal manipulation of stimulus position and gaze direction, we found that coding of gaze direction is independent of stimulus spatial coding. Our finding of a “gazedirection Simon effect” is congruent with the hypothesis that gaze direction is coded by a specialized mechanism.     

The shape of holes

The shape of holes can be recognized as accurately as the shape of objects (Palmer, S. E. (1999). Vision science: photons to phenomenology. Cambridge, MA: MIT Press), yet the area enclosed by a hole is a background region, and it can be demonstrated that background regions are not represented as having shape. What is therefore the shape of a hole, if any? To resolve this apparent paradox, we suggest that the shape of a hole is available indirectly from the shape of the surrounding object. We exploited the fact that observers are faster at judging the position of convex vertices than concave ones (Perception 30 (2001) 1295), and using a figural manipulation of figure/ground we found a reversal of the relative speeds when the same contours were presented as holes instead of objects. If contours were perceived as belonging to the hole rather than the surrounding object then there would have been no qualitative difference in responses to the object and hole stimuli. We conclude that the contour bounding a hole is automatically assigned to the surrounding object, and that a change in perception of a region from object to hole always drastically changes the encoded information. We discuss the many interesting aspects of holes as a subject of study in different disciplines and predict that much insight especially about shape will continue to come from holes.     

Psychache and suicidality in adult mood disordered outpatients in Brazil

Shneidman (e.g., 1998) has theorized that psychache--general psychological and emotional pain that reaches intolerable intensity--is an important suicide-related variable, and indeed, represents a source of suicidal behavior. This conceptualization, while prominent and clinically and intuitively appealing, has received relatively little empirical scrutiny. In this study, we determined whether an index closely related to psychache, psychological quality of life, would display a special and resilient association to suicidality among 60 adult psychiatric outpatients in Brazil. All patients underwent structured clinical interviews and completed various clinical and quality-of-life measures. We found that the association between psychological quality of life and suicidality remained, even when depression, hopelessness, and other domains of quality of life were controlled. Psychache appears to deserve its place among key suicide-related variables, and deserves the attention of clinicians working with suicidal people.