Drivers’ visual attention: A field study at intersections

Crossing a road intersection, a driver must collect visual information from various locations. The allocation of visual attention, which allows this collection, mainly relies on top-down processes. This study focuses on three top-down factors which influence the collection of visual information: the value of visual information for the ongoing task, their bandwidth, and the familiarity with the environment. These factors are studied according to the priority rules at intersections (Give way, Stop or Priority), the expected traffic density (Lower or Higher) and the number of passages (First or Second passage). Fourteen participants were installed in an instrumented vehicle equipped with an eye-tracker. They drove during 1h45 along a 80-km long route, mainly on rural roads, which included 19 intersections. Visual attention was studied by means of the head and gaze horizontal eccentricity. Effects were found for each of the three factors, in agreement with Wickens’ theoretical framework and with previous studies, despite the important variability in the data due to the experimental situation.     

Higher-order cognitive factors affect subjective but not proprioceptive aspects of self-representation in the rubber hand illusion

In the current study we look at whether subjective and proprioceptive aspects of selfrepresentation are separable components subserved by distinct systems of multisensory integration. We used the rubber hand illusion (RHI) to draw the location of the ‘self’ away from the body, towards extracorporeal space (Out Condition), thereby violating top-down information about the body location. This was compared with the traditional RHI which drew position of the ‘self’ towards the body (In Condition). We were successfully able to draw proprioceptive position of the limbs in and out from the body suggesting body perception is a purely bottom-up process, resistant to top-down effects. Conversely, we found subjective self-representation was altered by the violation of top-down body information – as the strong association of subjective and proprioceptive factors found in the In Condition became non-significant in the Out Condition. Interestingly, we also found evidence that subjective embodiment can modulate tactile perception.     

Sustained attention to spontaneous thumb sensations activates brain somatosensory and other proprioceptive areas

The present experiment was designed to test if sustained attention directed to the spontaneous sensations of the right or left thumb in the absence of any external stimuli is able to activate corresponding somatosensory brain areas. After verifying in 34 healthy volunteers that external touch stimuli to either thumb effectively activate brain contralateral somatosensory areas, and after subtracting attention mechanisms employed in both touch and spontaneous-sensation conditions, fMRI evidence was obtained that the primary somatosensory cortex (specifically left BA 3a/3b) becomes active when an individual is required to attend to the spontaneous sensations of either thumb in the absence of external stimuli. In addition, the left superior parietal cortex, anterior cingulate gyrus, insula, motor and premotor cortex, left dorsolateral prefrontal cortex, Broca’s area, and occipital cortices were activated. Moreover, attention to spontaneous-sensations revealed an increased connectivity between BA 3a/3b, superior frontal gyrus (BA 9) and anterior cingulate cortex (BA 32), probably allowing top-down activations of primary somatosensory cortex. We conclude that specific primary somatosensory areas in conjunction with other left parieto-frontal areas are involved in processing proprioceptive and interoceptive bodily information that underlies own body-representations and that these networks and cognitive functions can be modulated by top-down attentional processes.     

The modulation of reward priority by top-down knowledge

Reward-associated features capture attention automatically and continue to do so even when the reward contingencies are removed. This profile has led to the hypothesis that rewards belong to a separate class of attentional biases that is neither typically top-down nor bottom-up. The goal of these experiments was to understand the degree to which top-down knowledge can modulate value-driven attentional capture within (a) the timecourse of a single trial and (b) when the reward contingencies change explicitly over trials. The results suggested that top-down knowledge does not affect the size of value-driven attentional capture within a single trial. There were clear top-down modulations in the magnitude of value-driven capture when reward contingencies explicitly changed, but the original reward associations continued to have a persistent bias on attention. These results contribute to a growing body of evidence that reward associations bias attention through mechanisms separate from other top-down and bottom-up attentional biases.     

Whiteheadian Societies and Peirce's Law of Mind: Actuality and Potentiality in the Cosmic Process

Abstract

A more suitable philosophical position to counter the claims of scientific materialism re the nature of physical reality can possibly be found in combining the metaphysics of A.N. Whitehead and C.S. Peirce. Peirce postulated a habit-forming tendency or inbuilt potentiality of the cosmic process as a whole to move over time toward ever greater organization and more complex structure. But he is vague on how “the law of the mind” applies to nature below the level of human self-awareness. Whitehead's notion of actual entities (momentary self-constituting subjects of experience) as the “final real things of which the world is made up” logically allows for some primitive form of subjectivity with the requisite potentiality for habit-formation at all levels of existence and activity within nature. In addition, Whitehead's notion of structured societies made up of subsocieties with a “regnant” subsociety seems philosophically to justify the new emphasis on bottom-up rather than top-down causation in the emergence of more complex levels of existence and activity within the life-sciences.     

Do supplementary signs distract the driver?

In 2005, the regulation of signage on German highways was changed and now allows supplementary signs. These signs are installed below direction signs and inform about the services offered on motorway service areas. Being advertisement, the supplementary signs bear the risk to distract drivers looking for directional information. To study the influence of supplementary signs, four experiments (N = 30) were conducted. Experiment 1 used the phenomenon of change blindness as an indicator for the allocation of attention. It could be shown that drivers searching for a specific direction direct nearly no attention to the supplementary signs. In experiment 2 and 3, the influence of the supplementary signs on perceptional threshold for directional information and on self-chosen perception times was measured. Neither the perceptional threshold nor perception times freely chosen by the participants were negatively affected by the supplementary signs. The last experiment analyzed the influence of supplementary signs on driver reaction in a critical driving situation in a driving simulator study. Here, supplementary signs had no negative impact on collision rate and reaction time. Based on the results, it is concluded that drivers use effective attentional strategies while searching for directional information. In the experiments no negative effects of the supplementary signs could be found.     

On the influence of causal beliefs on the feeling of agency

The sense of agency is the experience of being the origin of a sensory consequence. This study investigates whether contextual beliefs modulate low-level sensorimotor processes which contribute to the emergence of the sense of agency. We looked at the influence of causal beliefs on ‘intentional binding’, a phenomenon which accompanies self-agency. Participants judged the onset-time of either an action or a sound which followed the action. They were induced to believe that the tone was either triggered by themselves or by somebody else, although, in reality, the sound was always triggered by the participants. We found that intentional binding was stronger when participants believed that they triggered the tone, compared to when they believed that another person triggered the tone. These results suggest that high-level contextual information influences sensorimotor processes responsible for generating intentional binding.     

Valence specific laterality effects in prosody: expectancy account and the effects of morphed prosody and stimulus lead

The majority of studies have demonstrated a right hemisphere (RH) advantage for the perception of emotions. Other studies have found that the involvement of each hemisphere is valence specific, with the RH better at perceiving negative emotions and the LH better at perceiving positive emotions [Reuter-Lorenz, P., & Davidson, R.J. (1981) Differential contributions of the 2 cerebral hemispheres to the perception of happy and sad faces. Neuropsychologia, 19, 609-613]. To account for valence laterality effects in emotion perception we propose an 'expectancy' hypothesis which suggests that valence effects are obtained when the top-down expectancy to perceive an emotion outweighs the strength of bottom-up perceptual information enabling the discrimination of an emotion. A dichotic listening task was used to examine alternative explanations of valence effects in emotion perception. Emotional sentences (spoken in a happy or sad tone of voice), and morphed-happy and morphed-sad sentences (which blended a neutral version of the sentence with the pitch of the emotion sentence) were paired with neutral versions of each sentence and presented dichotically. A control condition was also used, consisting of two identical neutral sentences presented dichotically, with one channel arriving before the other by 7 ms. In support of the RH hypothesis there was a left ear advantage for the perception of sad and happy emotional sentences. However, morphed sentences showed no ear advantage, suggesting that the RH is specialised for the perception of genuine emotions and that a laterality effect may be a useful tool for the detection of fake emotion. Finally, for the control condition we obtained an interaction between the expected emotion and the effect of ear lead. Participants tended to select the ear that received the sentence first, when they expected a 'sad' sentence, but not when they expected a 'happy' sentence. The results are discussed in relation to the different theoretical explanations of valence laterality effects in emotion perception.     

Varieties of cognitive penetration in visual perception

Is our perceptual experience a veridical representation of the world or is it a product of our beliefs and past experiences? Cognitive penetration describes the influence of higher level cognitive factors on perceptual experience and has been a debated topic in philosophy of mind and cognitive science. Here, we focus on visual perception, particularly early vision, and how it is affected by contextual expectations and memorized cognitive contents. We argue for cognitive penetration based on recent empirical evidence demonstrating contextual and top-down influences on early visual processes. On the basis of a perceptual model, we propose different types of cognitive penetration depending on the processing level on which the penetration happens and depending on where the penetrating influence comes from. Our proposal has two consequences: (1) the traditional controversy on whether cognitive penetration occurs or not is ill posed, and (2) a clear-cut perception–cognition boundary cannot be maintained.     

Carry-over of attentional settings between distinct tasks: A transient effect independent of top-down contextual biases

Top-down attentional settings can persist between two unrelated tasks, influencing visual attention and performance. This study investigated whether top-down contextual information in a second task could moderate this “attentional inertia” effect. Forty participants searched through letter strings arranged horizontally, vertically, or randomly and then made a judgement about road, nature, or fractal images. Eye movements were recorded to the picture search and findings showed greater horizontal search in the pictures following horizontal letter strings and narrower horizontal search following vertical letter strings, but only in the first 1000 ms. This shows a brief persistence of attentional settings, consistent with past findings. Crucially, attentional inertia did not vary according to image type. This indicates that top-down contextual biases within a scene have limited impact on the persistence of previously relevant, but now irrelevant, attentional settings.