ASTEF: A simple tool for examining fixations

In human factors and ergonomics research, the analysis of eye movements has gained popularity as a method for obtaining information concerning the operator's cognitive strategies and for drawing inferences about the cognitive state of an individual. For example, recent studies have shown that the distribution of eye fixations is sensitive to variations in mental workload---dispersed when workload is high, and clustered when workload is low. Spatial statistics algorithms can be used to obtain information about the type of distribution and can be applied over fixations recorded during small epochs of time to assess online changes in the level of mental load experienced by the individuals. In order to ease the computation of the statistical index and to encourage research on the spatial properties of visual scanning, A Simple Tool for Examining Fixations has been developed. The software application implements functions for fixation visualization, management, and analysis, and includes a tool for fixation identification from raw gaze point data. Updated information can be obtained online at www.astef.info, where the installation package is freely downloadable.     

New protocol for dissociating visuospatial working memory ability in reaching space and in navigational space

Several studies have demonstrated that the processing of visuospatial memory for locations in reaching space and in navigational space is supported by independent systems, and that the coding of visuospatial information depends on the modality of the presentation (i.e., sequential or simultaneous). However, these lines of evidence and the most common neuropsychological tests used by clinicians to investigate visuospatial memory have several limitations (e.g., they are unable to analyze all the subcomponents of this function and are not directly comparable). Therefore, we developed a new battery of tests that is able to investigate these subcomponents. We recruited 71 healthy subjects who underwent sequential and simultaneous navigational tests by using an innovative sensorized platform, as well as comparable paper tests to evaluate the same components in reaching space (Exp. 1). Consistent with the literature, the principal-component method of analysis used in this study demonstrated the presence of distinct memory for sequences in different portions of space, but no distinction was found for simultaneous presentation, suggesting that different modalities of eye gaze exploration are used when subjects have to perform different types of tasks. For this purpose, an infrared Tobii Eye-Tracking X50 system was used in both spatial conditions (Exp. 2), showing that a clear effect of the presentation modality was due to the specific strategy used by subjects to explore the stimuli in space. Given these findings, the neuropsychological battery established in the present study allows us to show basic differences in the normal coding of stimuli, which can explain the specific visuospatial deficits found in various neurological conditions.     

Crossing the pillars of Hercules: the role of spatial frames of reference in error making

This paper introduces a perspective accounting for errors that may occur as a result of the human interaction with the three-dimensional (3D) space. Particularly, we are interested in errors that are caused by cognitively crossing the boundary between peripersonal and extrapersonal space. Several behavioural, neurophysiological, and neuropsychological perspectives are reviewed in order to develop the theoretical framework on which our ideas are founded. We argue that cognitively crossing the boundary implies switching from one frame of reference to another, which, as a consequence, implies specific costs. The results of five experiments (overall involving 76 participants) support our hypothesis, suggesting the existence of different action-oriented spatial frames of reference.     

Switching between goals mediates the attentional blink effect

Humans are fundamentally limited in processing information from the outside world. This is particularly evident in the attentional blink (AB), the impaired ability to identify the second of two targets presented in close succession. We report findings from three experiments showing that the AB is significantly reduced when observers are set to achieve one single goal (reporting combinations of the two targets) instead of separate goals (reporting the two targets). This finding raises questions about the nature of AB, and suggests that processes involved in goal-switching must be taken into account by theories of the AB phenomenon.     

Resampling approach to statistical inference: Bootstrapping from event-related potentials data

We propose the use of the bootstrap resampling technique as a tool to assess the within-subject reliability of experimental modulation effects on event-related potentials (ERPs). The assessment of the within-subject reliability is relevant in all those cases when the subject score is obtained by some estimation procedure, such as averaging. In these cases, possible deviations from the assumptions on which the estimation procedure relies may lead to severely biased results and, consequently, to incorrect functional inferences. In this study, we applied bootstrap analysis to data from an experiment aimed at investigating the relationship between ERPs and memory processes. ERPs were recorded from two groups of subjects engaged in a recognition memory task. During the study phase, subjects in Group A were required to make an orthographic judgment on 160 visually presented words, whereas subjects in Group B were only required to pay attention to the words. During the test phase all subjects were presented with the 160 previously studied words along with 160 new words and were required to decide whether the current word was “old” or “new.” To assess the effect of word imagery value, half of the words had a high imagery value and half a low imagery value. Analyses of variance performed on ERPs showed that an imagery-induced modulation of the old/new effect was evident only for subjects who were not engaged in the orthographic task during the study phase. This result supports the hypothesis that this modulation is due to some aspect of the recognition memory process and not to the stimulus encoding operations that occur during the recognition memory task. However, bootstrap analysis on the same data showed that the old/new effect on ERPs was not reliable for all the subjects. This result suggests that only a cautious inference can be made from these data.     

Utilizing an Ability-Based Measure to Detect Emotion Regulation Deficits in Generalized Anxiety Disorder

In recent years, the field of emotion regulation has advanced current conceptualizations of many forms of psychopathology. Difficulties with emotion regulation have been detected via self-report in several anxiety and depressive disorders, and in particular, generalized anxiety disorder (GAD). However, there is a paucity of research examining emotion regulation ability in this population, leaving open the possibility that self-report measures reflect an individual’s perception of his/her emotion regulation skills rather than skills themselves. The present study examined the utility of an ability-based measure of emotional intelligence in the assessment of emotion-related deficits in GAD as well as the concordance between the ability-based measure and self-reports of emotion regulation skills. Results revealed that individuals with GAD demonstrated significantly more difficulty regulating their emotions than control participants did on both ability-based and self-report measures. Further, these measures showed a moderate concordance with each other. Findings suggest it will be important to integrate ability-based measurement of emotion-related deficits with other assessment modalities.     

Goal-completion processes affect the attentional blink

People are notably limited in processing information from the outside world. For instance, they frequently fail to identify the second of two targets presented in close succession (attentional blink, AB). Theories of the AB have mostly focused upon early stimuli processing. However, here we show that late, goal-completion processes play an important role. We report findings from a rapid serial visual presentation task with three targets (T1, T2, and T3). Participants set to achieve one single goal for T1 and T2 (reporting the sum of the two), and to detect T3, showed an AB effect upon T3 but not upon T2, while participants set to achieve separate goals for the three targets showed an AB effect upon both T2 and T3. This finding raises questions about the nature of AB, suggesting that theories of the AB must take into account processes involved in goal switching.     

Comparison of isokinetic peak force and power in adults with partial and total blindness

For many populations the ability to move efficiently is compromised by an impaired muscular functioning. Strength development is necessary to overcome the effects of gravity to maintain posture and generate movement responses for mobility. The strength and power capabilities of individuals with total blindness (n = 12) were compared to those with partial vision (n = 12) to evaluate effects of vision on performance. Results indicate that (1) no significant differences were apparent between total blindness and partial vision, (2) significant sex differences were evident in each group, and (3) better performance was apparent at lower velocities. It was concluded that physical performance in individuals with blindness and partial vision are equally deficient.     

Caregiver-patient dyads: Documenting the verbal instructions caregivers provide in joint cognitive tasks

Thirty spousal caregivers and their partners (who had been diagnosed as having primary degenerative dementia) jointly performed four cognitive tasks: Block Design (from the WAIS-R), the Token Test, and two memory tasks. Two of the tasks were unstructured, and two were structured. Caregivers served as the instructor on all tasks. Interactions were videotaped. Results showed that caregivers provided appropriate verbal instructions to a greater extent on the unstructured nonverbal task (Block Design) than on the unstructured memory task. Results are discussed in terms of implications for dyadic cognition research and intervention in dementia.