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.     

Ignorance is bliss: the role of observer expectation in dynamic spatial tuning of the attentional focus

When two sequential targets (T1, T2) are inserted in an RSVP stream of distractors, perception of T2 is impaired at intertarget lags shorter than 700 msec. Paradoxically, this deficit disappears when T2 is presented directly after T1 (lag-1 sparing). Visser, Bischof, and Di Lollo (1999) found that lag-1 sparing occurs only when T1 and T2 are presented in the same stream. In contrast, Shih (2000) obtained lag-1 sparing with targets insepa-rate streams. Four experiments addressed this inconsistency and revealed lag-1 sparing with targets in different streams, but only when observers had no foreknowledge of T1's location. We hypothesized that when T1 location is known, attention is focused narrowly on that stream; if T2 then appears in the other stream it is missed, and lag-1 sparing does not occur. When T1 location is not known, attention is focused broadly, encompassing both streams, and lag-1 sparing ensues.     

Parents' representations of their children: an exploratory study using the Osgood Semantic Differential Scales

The results of an exploratory national study carried out in Italy using Osgood's Semantic Differential Scales (Osgood, Suci, & Tannenbaum, 1957) with parents of 100 normal 6- to 11-yr.-old children in mainstream classrooms are reported. The aim was to devise a simple tool to be used to explore parents' perceptions of their children in this age group. Parents were asked to rate "my child" using some of Osgood's Semantic Differential Scales especially adapted for this study. Participants were 97 fathers and 100 mothers. Fathers were 32 to 57 years of age (M = 43.2, SD = 5.4), mothers were 29 to 49 years of age (M = 39.7, SD =4.4). In factor analysis four factors were identified: Activity, Evaluation, Emotions evoked by the child, Personality/Physical contact. Average factor scores were significantly different. There were no significant differences between fathers and mothers on the four factor scores. Children were more positively evaluated the younger they were.     

The time required for perceptual (nonmotoric) processing in IOR

In an inhibition of return (IOR) paradigm, we used a threshold-tracking procedure combined with backward masking to measure the speed of perceptual processing in IOR independent of motoric factors. Instead of the conventional reaction time measure, this procedure yielded the critical exposure duration (DUR_c) that is required in order for a target to be identified reliably before the onset of a trailing mask. In Experiment 1, the facilitation effects conventionally found at short cue—target onset asynchrony (CTOA) were evidenced by shorter values of DUR_c at cued relative to uncued locations. Conversely, the retardation effects conventionally found at long CTOA were evidenced by correspondingly longer values of DUR_c. In Experiment 2, the DUR_c results strongly suggest that the directional reading bias previously observed in IOR studies is due, at least in part, to perceptual rather than motoric factors.     

The role of coping, anxiety, and stress in depression post-acute coronary syndrome

Depressive symptoms are common and can affect prognosis following acute coronary syndromes (ACS). This study examined the psychological factors, coping, anxiety, and perceived stress associated with depression following ACS. Psychological variables were assessed in 15 females and 66 males (M = 57 years, SD = 12). Repeated measures at 2, 12, and 24 weeks post-ACS compared depression, anxiety, perceived stress, and coping resources as determined by the Cardiac Depression Scale, Beck Depression Inventory-II, State Trait Anxiety Inventory, Perceived Stress Scale, and Coping Resources Inventory. Depression, anxiety, and perceived stress remained high in the depressed group across time. Coping scores at 2 weeks post-ACS predicted depression scores at 24 weeks post-ACS. It appears that trait anxiety and coping resources are related to depressive symptoms post-ACS.     

Are spatial selection and identity extraction separable when attention is controlled endogenously?

Visual search for a target involves two processes: spatial selection and identity extraction. Ghorashi, Enns, and Di Lollo (2008) found these processes to be independent and surmised that they were carried out along distinct visual pathways: dorsal and ventral, respectively. The two experiments that are described in the present article evaluated this hypothesis. Attentional-blink methodology was combined with voluntary spatial cuing in a visual search task: Intertarget lag was used to manipulate identity extraction; predictive cues were used to signal target locations. Central digit cues in Experiment 1 required participants to identify digits before voluntarily directing attention to a corresponding location, whereas flashed dots in Experiment 2 (indicating an opposite location) required attentional redeployment without prior cue identification. Consistent with the dual-pathway hypothesis, cuing was impaired only when the first target and the number cue competed for ventral-pathway mechanisms. Collectively, the results support the dual-pathway account of the separability of spatial selection and identity extraction.     

Temporal information coding properties of a network of inhibitory interneurons

Inhibitory interneurons are coupled by electrical and inhibitory synapses and exert a powerful control of the discharges of principal cells. In this paper, the transmission properties of excitatory synaptic inputs by a network of interneurons, are studied by using a computational approach. It is shown that both the rise and decay time constants, describing the time course of the excitatory synaptic inputs, have a strong effect on the output jitter of the fired spikes. Similar results were found by changing the values of the other parameters describing the network. Lastly, it is shown that the presence of the electrical coupling between interneurons confers to the network the capability of transmitting, with less temporal spread, the timing information contained in its inputs.     

从词频和新旧效应探讨再认测验中的定向遗忘

本文采用字表方式,从高低词频和新旧效应角度,探讨内隐和外显测验中定向遗忘效应的存在性及其机制问题。结果发现:(1)低频词在两种测验中都存在定向遗忘效应,而高频词仅存在于外显测验中。(2)两种测验中都存在指示记住的新旧效应,而外显测验中不存在指示忘记的新旧效应。由此推断,测验间在没有"意识和无意识"相互污染的理想情况下,只有外显测验可获得定向遗忘效应;定向遗忘的机制可能是选择性编码机制。     

Visual search is postponed during the attentional blink until the system is suitably reconfigured

J. S. Joseph, M. M. Chun, and K. Nakayama (1997) found that pop-out visual search was impaired as a function of intertarget lag in an attentional blink (AB) paradigm in which the 1st target was a letter and the 2nd target was a search display. In 4 experiments, the present authors tested the implication that search efficiency should be similarly impaired (steeper search slopes at shorter lags). A conventional AB deficit was found, but, contrary to expectations, search slopes were invariant with lag. These results suggest that no search can be carried out during the period of the AB. Instead, the search is postponed until after the 1st target has been processed. The authors conclude that efficient visual search cannot be carried out unless the visual system is configured appropriately for the search task. If the initial configuration is inappropriate, processing of the 2nd target is held in abeyance until the system has been suitably reconfigured.