Timing behavior and conditioned fear

Rats were trained on a two-response timing procedure which required that response B follow response A by at least a minimum specified interval in order to be reinforced with food. Repeated presentation (5 min on, 5 min off) of an auditory warning stimulus terminated by a brief electric shock to the feet (conditioned fear) produced a marked suppression in the frequency of A-to-B response sequences during the warning stimulus. The distribution of A-to-B interresponse times (timing behavior), however, did not change during the warning stimulus.     

Effects of visual-field and matching instruction on event-related potentials and reaction time

Vertical letter pairs were presented randomly in the left and right visual hemifields in a physical identity match and name identity match condition. The reaction times showed a right visual field superiority for name matches, and a left visual field superiority for physical matches. Event-related potentials to letter pairs showed a sequence of three waves: a negative wave (N2, around 270 msec), a positive wave (P3, around 500 msec), and a broad positive slow wave (SW, around 600-700 msec), respectively. P3 and SW amplitudes were consistently larger at the left hemisphere than at the right hemisphere, regardless of the field of stimulation. At both hemispheres, N2 waves were always larger to stimuli presented in the visual field contralateral to a hemisphere than stimuli presented in the visual field ipsilateral to a hemisphere. The positive waves (P3, SW) showed the opposite pattern: smaller amplitudes to stimuli that were presented contralaterally than stimuli that were presented ipsilaterally to a given hemisphere. These results were attributed to a shift in sustained negativity on the directly stimulated hemisphere, relative to the indirectly stimulated hemisphere, reflecting either sensory at attentional processes in the posterior cerebral hemispheres.     

The Sound of Grasp Affordances: Influence of Grasp‐Related Size of Categorized Objects on Vocalization

Previous research shows that simultaneously executed grasp and vocalization responses are faster when the precision grip is performed with the vowel [i] and the power grip is performed with the vowel [ɑ]. Research also shows that observing an object that is graspable with a precision or power grip can activate the grip congruent with the object. Given the connection between vowel articulation and grasping, this study explores whether grasp‐related size of observed objects can influence not only grasp responses but also vowel pronunciation. The participants had to categorize small and large objects into natural and manufactured categories by pronouncing the vowel [i] or [ɑ]. As predicted, [i] was produced faster when the object's grasp‐related size was congruent with the precision grip while [ɑ] was produced faster when the size was congruent with the power grip (Experiment 1). The effect was not, however, observed when the participants were presented with large objects that are not typically grasped by the power grip (Experiment 2). This study demonstrates that vowel production is systematically influenced by grasp‐related size of a viewed object, supporting the account that sensory‐motor processes related to grasp planning and representing grasp‐related properties of viewed objects interact with articulation processes. The paper discusses these findings in the context of size–sound symbolism, suggesting that mechanisms that transform size‐grasp affordances into corresponding grasp‐ and articulation‐related motor programs might provide a neural basis for size‐sound phenomena that links small objects with closed‐front vowels and large objects with open‐back vowels.     

Transformative Choice,Practical Reasons and Trust

Abstract

In this article I reflect on the question of whether we can have reason to make transformative choices. In attempting to answer it, I do three things. First, I bring forward an internalist account of practical reasons which entails the idea that agents should deliberate to the best of their ability. Second, I discuss L.A. Paul’s views on transformative choice, arguing that, although they present a real problem, the problem is not as profound as she believes it is. Third, I argue that, given the situation in which we face transformative choices (a situation of principled uncertainty though not cluelessness), trust is an appropriate response to transformative choices, and that when one’s trust that one’s current desires will be fulfilled in making a transformative choice is reasonable, one has a reason to make it. Thus, trust turns out to be a crucial response to a profound problem each of us will face during our lives.     

RETRACTED ARTICLE: Unexpected events disrupt visuomotor working memory and increase guessing

When an unexpected event, such as a car horn honking, occurs in daily life, it often disrupts our train of thought. In the lab, this effect was recently modeled with a task in which verbal working memory (WM) was disrupted by unexpected auditory events (Wessel et al. in Nature Communications, 7, 11195, 2016). Here we tested whether this effect extends to a different type of WM—namely, visuomotor. We found that unexpected auditory events similarly decremented visuomotor WM. Moreover, this effect persisted for many more trials than had previously been shown for verbal WM, and the effect occurred for two different types of unexpected auditory events. Furthermore, we found that unexpected events decremented WM by decreasing the quantity, but not necessarily the quality, of items stored. These results showed an impact of unexpected events on visuomotor WM that was statistically robust and endured across time. They also showed that the effect was based on an increase in guessing, consistent with a neuroscience-inspired theory that unexpected events “wipe out” WM by stopping the ongoing maintenance of the trace. This new task paradigm is an excellent vehicle for further explorations of distractibility.     

Aging affects attunement in perceiving length by dynamic touch

Earlier studies have revealed age-dependent differences in perception by dynamic touch. In the present study, we examined whether the capacity to learn deteriorates with aging. Adopting an ecological approach to learning, the authors examined the process of attunement--that is, the changes in what informational variable is exploited. Young and elderly adults were trained to perceive the lengths of unseen, handheld rods. It was found that the capacity to attune declines with aging: Contrary to the young adults, the elderly proved unsuccessful in learning to detect the specifying informational variables. The fact that aging affects the capacity to attune sets a new line of research in the study of perception and perceptual-motor skills of elderly. The authors discuss the implications of their findings for the ongoing discussions on the ecological approach to learning.     

Attitudinal Approaches to Health Behavior: Integrating Expectancy‐Value and Automaticity Accounts

Attitudes are a key construct in health psychology due to their central role in motivating and changing behavior. An expectancy‐value framework has been the dominant conceptual approach for exploring the impact of attitudes on health behavior, applications of which emphasize volition and rational decision making. More recently, attention has focused on automatic attitudes, which are believed to capture reflexive aspects of motivation. Dual‐process models such as the MODE generally treat expectancy‐value and automaticity accounts as representing separate processing pathways. However, both accounts depend on associative learning. Learning history pairs beliefs or features with evaluations; subsequent activation of beliefs or features activates associated evaluations and drives overall attitude. Therefore, a single information processing architecture may accommodate expectancy‐value and automaticity approaches within a unifying framework, and this is provided by neural network (connectionist) accounts. In this paper, we highlight how a greater emphasis on the information processing mechanics of associative learning can provide a more parsimonious model of attitudes, which may also extend to a wider array of memory‐related phenomena of relevance to health psychology.     

Local contrast in natural images: normalisation and coding efficiency

The visual system employs a gain control mechanism in the cortical coding of contrast whereby the response of each cell is normalised by the integrated activity of neighbouring cells. While restricted in space, the normalisation pool is broadly tuned for spatial frequency and orientation, so that a cell's response is adapted by stimuli which fall outside its 'classical' receptive field. Various functions have been attributed to divisive gain control: in this paper we consider whether this output nonlinearity serves to increase the information carrying capacity of the neural code. 46 natural scenes were analysed with the use of oriented, frequency-tuned filters whose bandwidths were chosen to match those of mammalian striate cortical cells. The images were logarithmically transformed so that the filters responded to a luminance ratio or contrast. In the first study, the response of each filter was calibrated relative to its response to a grating stimulus, and local image contrast was expressed in terms of the familiar Michelson metric. We found that the distribution of contrasts in natural images is highly kurtotic, peaking at low values and having a long exponential tail. There is considerable variability in local contrast, both within and between images. In the second study we compared the distribution of response activity before and after implementing contrast normalisation, and noted two major changes. Response variability, both within and between scenes, is reduced by normalisation, and the entropy of the response distribution is increased after normalisation, indicating a more efficient transfer of information.     

Dancing shapes: a comparison of luminance-induced distortions

We present an illusory display in which a grid of outlined squares is positioned in front of a moving luminance gradient. Observers perceive a strong, illusory, 'wavelike' motion of the superimposed squares. We compared luminance effects on dynamic and static aspects of this illusion. The dynamic aspect was investigated by means of a temporal gradient, which induced an illusory pulsing of the outlined squares. The static aspect was investigated in two different ways. In one experiment, the outlined squares were positioned on a spatial gradient, which caused the squares to look like trapezoid shapes. In another experiment, the squares were positioned on different luminance fields, which affected their apparent size. In all experiments, luminance settings were the same, and observers were asked to indicate the direction and strength of the induced distortions. The overall results show large agreements between the dynamic distortion and the first-mentioned static distortion, whereas different tendencies emerged for the second static distortion. In a second series of experiments, we examined these distortions for various ranges of the luminance gradient and for border gradients as well. On the basis of these data, we explored how the directions of the perceived distortions of the single-gradient displays examined in this paper could be related to each other.