Philosophers of perception frequently assume that we see actual states of affairs, or facts. Call this claim factualism. In his book, William Fish suggests that factualism is supported by phenomenological observation as well as by experimental studies on multiple object tracking and dynamic feature-object integration. In this paper, I examine the alleged evidence for factualism, focusing mainly on object detection and tracking. I argue that there is no scientific evidence for factualism. This conclusion has implications for studies on the phenomenology (...) and epistemology of visual perception. (shrink)

Sustained neural activity during the delay phase of spatial working memory tasks is compelling evidence for the neural correlate of active storage and maintenance of spatial information, however, it does not provide insight into specific mechanisms of spatial coding. This activity may reflect a range of processes, such as maintenance of a stimulus position or a prepared motor response plan. The aim of our study was to examine neural evidence for the use of different coding strategies, depending on the characteristics (...) and demands of a spatial working memory task. Thirty-one and 44 participants performed a spatial working memory task while we measured their brain activity using fMRI in two separate experiments. Participants were asked to remember the position of a briefly presented target stimulus and, after a delay period, to use a joystick to indicate either the position of the remembered target or an indicated non-matching location. The task was designed so that the predictability of the response could be manipulated independently of task difficulty and memory retrieval process. We were particularly interested in contrasting conditions in which participants could use prospective coding of the motor response or had to rely on retrospective sensory information. Prospective motor coding was associated with activity in somatomotor, premotor, and motor cortices and increased integration of brain activity with and within the somatomotor network. In contrast, retrospective sensory coding was associated with increased activity in parietal regions and increased functional connectivity with and within secondary visual and dorsal attentional networks. The observed differences in activation levels, dynamics of differences over trial duration, and integration of information within and between brain networks provide compelling evidence for the use of complementary spatial working memory strategies optimized to meet task demands. (shrink)

Selective attention depends on goal-directed and stimulus-driven modulatory factors, each relayed by different brain rhythms. Under certain circumstances, stress-related states can change the balance between goal-directed and stimulus-driven factors. However, the neuronal mechanisms underlying these changes remain unclear. In this study, we explored how psychosocial stress can modulate brain rhythms during an attentional task and a task-free period. We recorded the EEG and ECG activity of 42 healthy participants subjected to either the Trier Social Stress Test, a controlled procedure to (...) induce stress, or a comparable control protocol, flanked by an attentional task, a 90 s of task-free period and a state of anxiety questionnaire. We observed that psychosocial stress induced an increase in heart rate, self-reported anxiety, and alpha power synchronization. Also, psychosocial stress evoked a relative beta power increase during correct trials of the attentional task, which correlates positively with anxiety and heart rate increase, and inversely with attentional accuracy. These results suggest that psychosocial stress affects performance by redirecting attentional resources toward internal threat-related thoughts. An increment of endogenous top-down modulation reflected an increased beta-band activity that may serve as a compensatory mechanism to redirect attentional resources toward the ongoing task. The data obtained here may contribute to designing new ways of clinical management of the human stress response in the future and could help to minimize the damaging effects of persistent stressful experiences. (shrink)

The awareness of death is a central motivating force behind human activity. Their capacities for abstract and symbolic reasoning give human beings a unique foresight of their finite lifetime and forthcoming demise.Because of the overwhelming nature of this realization; we try to cope with the ensuing anxieties by means of various cognitive and existential strategies. One such strategy is to create a meaningful legacy during one’s lifetime that will outlive the single individual. Whole-brain emulation is another approach; but is unusual (...) because of its literal promise to abolish death. Starting from the premise that WBE is feasible and will advance to such a level that we can speak of uploaded minds; we explore the implications of an allegedly immortal existence in a computational substrate: for our embodiment in the first place; and for death anxiety in the second. We argue that uploading would change the nature of; but could ultimately never abolish; embodiment. Instead; the defining characteristic of all brains are their vital links to the bodies that contain them and their interactions with the environment that are mediated by the body. In this light; we discuss the limits of WBE’s potential to mitigate death anxieties: limits related to the probability of ceasing to exist; but also those that stem from the perception of the body as a proxy for death. (shrink)