The attentional requirements of consciousness

It has been widely claimed that attention and awareness are doubly dissociable and that there is no causal relation between them. In support of this view are numerous claims of attention without awareness, and awareness without attention. Although there is evidence that attention can operate on or be drawn to unconscious stimuli, various recent findings demonstrate that there is no empirical support for awareness without attention. To properly test for awareness without attention, we propose that a stimulus be studied using a battery of tests based on diverse, mainstream paradigms from the current attention literature. When this type of analysis is performed, the evidence is fully consistent with a model in which attention is necessary, but not sufficient, for awareness.     

Differential activation patterns of occipital and prefrontal cortices during motion processing: Evidence from normal and schizophrenic brains

Visual motion perception is normally mediated by neural processing in the posterior cortex. Focal damage to the middle temporal area (MT), a posterior extrastriate region, induces motion perception impairment. It is unclear, however, how more broadly distributed cortical dysfunction affects this visual behavior and its neural substrates. Schizophrenia manifests itself in a variety of behavioral and perceptual abnormalities that have proved difficult to understand through a dysfunction of any single brain system. One of these perceptual abnormalities involves impaired motion perception. Motion processing provides an opportunity to clarify the roles of multiple cortical networks in both healthy and schizophrenic brains. Using fMRI, we measured cortical activation while participants performed two visual motion tasks (direction discrimination and speed discrimination) and one nonmotion task (contrast discrimination). Normal controls showed robust cortical activation (BOLD signal changes) in MT during the direction and speed discrimination tasks, documenting primary processing of sensory input in this posterior region. In patients with schizophrenia, cortical activation was significantly reduced in MT and significantly increased in the inferior convexity of the prefrontal cortex, an area that is normally involved in higher level cognitive processing. This shift in cortical responses from posterior to prefrontal regions suggests that motion perception in schizophrenia is associated with both deficient sensory processing and compensatory cognitive processing. Furthermore, this result provides evidence that in the context of broadly distributed cortical dysfunction, the usual functional specificity of the cortex becomes modified, even across the domains of sensory and cognitive processing.     

Experiential response and intention to purchase in the cocreative consumption of music: The Nine Inch Nails experiment

Customers allowed to cocreate products are more willing to purchase them eventually because of not only their utilitarian but also their hedonic and experiential value. Experiential responses seem especially relevant in the cocreative consumption of cultural and intangible goods, such as music. To examine how such intangible aspects of cocreation can influence a consumer's intention to purchase, we let two groups of participants rate their experience consuming music in either a traditional or cocreative way, in an experimental situation inspired by the work of American rock band Nine Inch Nails. Participants in the traditional group had to passively watch a series of music videos; participants in the cocreative group were tasked to produce a video montage using the same material. In the traditional group, purchase intention was predicted by music quality, mediated by willingness to reexperience; in the cocreative group, however, purchase intention was only predicted by the consumers' experiential response, with no mediation of either music quality or willingness to reexperience. Additionally, the overall experiential response to music was lower in the cocreative group than in the traditional group, leading to lower intention to purchase. These results suggest that cocreated value for intangible goods is predicted at least as much by the consumers' experiential response as by their evaluation of product quality. It also suggests that there is nothing systematically positive in having consumers participate in the coproduction of intangible goods and that research is needed to identify the factors predicting the perceived quality of a cocreative experience. Copyright © 2015 John Wiley & Sons, Ltd.     

Amodal representation of occluded surfaces: role of invisible stimuli in apparent motion correspondence

A series of demonstrations were created where the perceived depth of targets was controlled by stereoscopic disparity. A closer object (a cloud) was made to jump back and forth horizontally, partially occluding a farther object (a full moon). The more distant moon appeared stationary even though the unoccluded portion of it, a crescent, changed position. Reversal of the relative depth of the moon and cloud gave a totally different percept: the crescent appeared to flip back and forth in the front depth plane. Thus, the otherwise-robust apparent motion of the moon crescents was completely abolished in the cloud-closer case alone. This motion-blocking effect is attributed to the 'amodal presence' of the occluded surface continuing behind the occluding surface. To measure the effect of this occluded 'invisible' surface quantitatively, a bistable apparent motion display was used (Ramachandran and Anstis 1983a): two small rectangular-shaped targets changed their positions back and forth between two frames, and the disparity of a large centrally positioned rectangle was varied. When the perceived depths supported the possibility of amodal completion behind the large rectangle, increased vertical motion of the targets was found, suggesting that the amodal presence of the targets behind the occluder had effectively changed the center position of the moving targets for purposes of motion correspondence. Amodal contours are literally 'invisible', yet it is hypothesized that they have a neural representation at sufficiently early stages of visual processing to alter the correspondence solving process for apparent motion.     

Distinct mechanisms for the representation of moving and static objects

The visual system has been suggested to integrate different views of an object in motion. We investigated differences in the way moving and static objects are represented by testing for priming effects to previously seen ("known") and novel object views. We showed priming effects for moving objects across image changes (e.g., mirror reversals, changes in size, and changes in polarity) but not over temporal delays. The opposite pattern of results was observed for objects presented statically; that is, static objects were primed over temporal delays but not across image changes. These results suggest that representations for moving objects are: (1) updated continuously across image changes, whereas static object representations generalize only across similar images, and (2) more short-lived than static object representations. These results suggest two distinct representational mechanisms: a static object mechanism rather spatially refined and permanent, possibly suited for visual recognition, and a motion-based object mechanism more temporary and less spatially refined, possibly suited for visual guidance of motor actions.     

Priming of popout: III. A short-term implicit memory system beneficial for rapid target selection

The priming of popout (PoP) (Maljkovic & Nakayama, 1994, 1996) increases the speed of attentional deployment to subsequent targets having the same feature characteristic and relative position, it lasts for approximately 5-8 trials, and is cumulative. Here we establish PoP as an example of short-term implicit memory by showing that it is qualitatively different from explicit memory. Using a post-cued recall procedure embedded in the stream of search task trials, we show that explicit memory is not selective as is PoP and is of much shorter duration. As such we argue that explicit memory is unlikely to account for the properties of PoP. In examining the decay of PoP, we find that: PoP is not evident after a 90sec delay, it does not show passive decay over much shorter intervals (1-3sec), and it gets decremented by attentional deployments to visually dissimilar stimuli, the size of the decrement being related to task difficulty. The results, taken together, suggest that PoP reflects a functionally beneficial memory system, specialized for the rapid and automatic selection of items for focal attention and saccadic eye movements.     

Numeric comparison in a visually-guided manual reaching task

Nearly all studies on perception and cognition have used discrete responses to infer internal cognitive processes. In the current study, we demonstrate that visually-guided manual reaching can provide new opportunities to access internal processes over time. In each trial, participants were required to compare a single digit Arabic number presented on the center square with the standard, 5. Participants were asked to reach and touch one of three squares on the screen with their index finger while their hand movement trajectories were recorded: the left square for 1-4, the center for 5, and the right for 6-9. Direct evidence for an analogue representation of numbers was found in early as well as in later portions of hand trajectories, showing systematic shifts in position for small differences in numerical magnitude.     

Differential Effect of Two Mental Stress Tasks on Arterial Stiffness

Acute mental stress is believed to induce transient arterial dysfunction, but relatively few data are available. We therefore examined the effect of mental stress tasks that could induce differential hemodynamic responses on arterial dysfunction. Forty‐eight participants conducted either a mental arithmetic (MA) task or a mirror‐tracing (MT) task. Cardiovascular indices and arterial stiffness were measured before, during, and after these tasks. Analysis revealed that increases in arterial stiffness during the task and during recovery were more pronounced for the MA than for the MT, and that evoked hemodynamic response was more myocardial for MA than for MT. These results clearly show that MA and MT tasks that induce differential hemodynamic responses have a differential effect on arterial stiffness. This finding sheds light on the underlying mechanism that may account for the relationship between cardiovascular reactivity and cardiovascular disease.