Based on previous research showing the usefulness of spatial statistics in detecting randomness in the distribution of eye fixations, this study investigated the ocular behavior of professional pilots engaged in a simulated flight. The distribution of eye fixations was used as an indirect index of mental workload: Eye movements were recorded during the different phases (departure to landing) of a simulated flight and were analyzed using spatial statistics algorithms. Results showed sensitivity of spatial dispersion indices to variations in mental workload: higher during departure and landing, lower during climb and descend, and the lowest during the cruise phase. This finding provides additional evidence of the utility of fixations distribution as a real-time measure of mental workload and, consequently, as a trigger for adaptive automation.

Wepropose 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 Awere required to make an orthographic judgment on 160visually 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 160previously studied words along with 160new 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.Functional inferences from studies in cognitive neuroscience are often based on sets of methodological assumptions whose validity is not always evident For example, since in event-related potential (ERP) research the low signal-to-noise ratio makes it generally impossible to analyze the electrocerebral response to a single stimulus, such a brain response needs to be estimated, usually through an averaging procedure. The mathematical model that underlies averaging (De Weerd, 1981;De Weerd & Martens, 1978;Woody, 1967) holds that the electrocerebral activity recorded upon the presentation of a stimulus is the sum of the brain response to that stimulus (signal) and the spontaneous brain activity independent of it (noise), Furthermore, the model holds that the brain response is invariant with respect to different occurrences of the same stimulus, and that the spontaneous brain activity is drawn from a zero-mean random process. Under these assumptions, averaging gives a reliable estimate of the true brain response when applied to a large number of occurrences ofthe same stimulus. The assumptions on which the averaging procedure is founded, however, are often questionable. In particu...

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.

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The purpose of this study was to investigate whether the lower visual field advantage reported on a number of visual tasks depends on the activity of neural systems which process information from different spaces. To this end, a double dissociation logic was followed by observing the effects of visual and spatial interference on a relocation memory task performed by 80 volunteers. Results showed that participants were better at relocating stimuli presented in the lower than in the upper visual field. Moreover, a concurrent spatial task, but not a concurrent visual task, disrupted the visual field vertical asymmetry. Those findings confirm that the vertical asymmetry of visual field depends on the spatial processing of incoming stimuli.