Inner speech sustains predictable task switching: direct evidence in adults

It has been proposed that inner speech supports task selection in task-switching studies, especially when the need for endogenous control is increased. This has been established through the suppression of inner speech in cognitive-flexibility tasks that leads to poorer performance. The aim of this study is to quantify the role of inner speech in a flexibility task by using surface laryngeal electromyography, which, contrary to previous studies, enables participants to freely verbalise the tasks. We manipulated endogenous and exogenous flexibility in a mathematical switching task paradigm. Experiment 1 shows that inner speech acts as a support for switching and is recruited more often when the tasks are of an endogenous type. The main result of Experiment 2 that language is recruited more for the mixing cost than for the switch cost (regardless of the endogenous factor) extends past findings obtained through articulatory suppression.     

Numerosity-length interference: a Stroop experiment

The existence of a common mechanism for length and numerosity processing was tested with a Stroop task. Participants compared the length or the numerosity of arrays of dots, for which the two variables were manipulated independently to create congruent, incongruent, or neutral pairs. Results showed that the spatial cues strongly interfered with the processing of numerosity, whereas the numerical cues only moderately interfered with the processing of length. These findings reflect a different mandatory processing of numerosity and length.     

Deliberating Risks Under Uncertainty: Experience, Trust, and Attitudes in a Swiss Nanotechnology Stakeholder Discussion Group

Scientific knowledge has not stabilized in the current, early, phase of research and development of nanotechnologies creating a challenge to ‘upstream’ public engagement. Nevertheless, the idea that the public should be involved in deliberative discussions and assessments of emerging technologies at this early stage is widely shared among governmental and nongovernmental stakeholders. Many forums for public debate including focus groups, and citizen juries, have thus been organized to explore public opinions on nanotechnologies in a variety of countries over the past few years. In Switzerland the Centre for Technology Assessment (TA-Swiss) organized such a citizen panel in fall 2006. Drawing from an ethnographic study of this panel called ‘publifocus on nanotechnologies, health, and environment’ this paper looks at the ways members of a stakeholder group deal with the epistemic uncertainty in their deliberation of nanotechnologies. By exploring the statements of the participants in the stakeholder discussion group, this paper reconstructs the narratives that constitute the epistemic foundations of the participants’ evaluations of nanotechnologies.

Waiting for more: the performance of domestic dogs (Canis familiaris) on exchange tasks

Five domestic dogs (Canis familiaris) were tested in a cooperative exchange task with an experimenter, as previously tested in non-human primates. In the first task, the dogs exchanged to maximise payoffs when presented with food items of differing quality. All consistently exchanged lower-value for higher-value rewards, as determined by their individual food preference, and exchanges corresponded significantly with the spontaneous preferences of three dogs. Next, all subjects demonstrated an ability to perform two and three exchanges in succession, to gain both qualitative and quantitatively increased rewards (group mean = 72 and 92% successful triple exchanges, respectively). Finally, the ability to delay gratification over increasing intervals was tested; the dogs kept one food item to exchange later for a larger item. As previously reported in non-human primates, there was considerable individual variation in the tolerance of delays, between 10 s and 10 min for the largest rewards. For those who reached longer time lags (>40 s), the dogs gave up the chance to exchange earlier than expected by each subject’s general waiting capacity; the dogs anticipated delay duration and made decisions according to the relative reward values offered. Compared to primates, dogs tolerated relatively long delays for smaller value rewards, suggesting that the socio-ecological history of domestic dogs facilitates their performance on decision-making and delay of gratification tasks.     

Role of the sympathetic nervous system in cerebrovascular responses to air-jet stress in rats

This study examined the role of sympathetic nerves in the control of cerebral hemodynamics during air-jet stress. In adult male Sprague-Dawley rats, blood flow velocity (pulsed Doppler) was measured in both internal carotid arteries 1 week after excision of one superior cervical ganglion. Blood pressure (BP) and carotid blood flows (CBFs) were simultaneously recorded during exposure to air-jet stress. In 5 out of 13 rats, stress was applied after β(2)-adrenoceptor blockade with ICI 118551 (0.4 mg/kg, then 0.2 mg/kg/h, i.v). Stress evoked an immediate rise in BP, CBFs, and vascular conductances. Vasodilatation was much larger on the denervated side than on the intact side (mean ± SEM: 78 ± 7 versus 19 ± 4%; P < 0.02) and lasted about 10 s. Thereafter, blood flows returned to or near normal and showed parallel variations while BP remained elevated. There was, therefore, a net vasoconstriction on both sides. In ICI 118551-treated rats, the initial vasodilatation was not significantly reduced on the denervated side (64 ± 4%), but the subsequent vasoconstriction was enhanced (P < 0.05) on both sides. In conclusion, air-jet stress evokes an immediate, short-lasting vasodilatation through a mechanism unrelated to β(2)-adrenoceptor stimulation. Sympathetic nerves powerfully limit this phenomenon, and thus contribute to protect the cerebral circulation from stress-induced BP surges.     

Diagnostic colours contribute to the early stages of scene categorization: Behavioural and neurophysiological evidence

We examined the effects of colour cues on the express categorization of natural scenes. Using a go/no-go paradigm sensitive to fast recognition processes, we measured early event-related potential (ERP) correlates of scene categorization to elucidate the processing stage at which colour contributes to scene recognition. Observers were presented with scenes belonging to four colour-diagnostic categories (desert, forest, canyon and coastline). Scenes were presented in one of three forms: Diagnostically coloured, nondiagnostically coloured, or greyscale images. In a verification task, observers were instructed to respond whenever the presented stimulus matched a previously presented category name. Reaction times and accuracy were optimal when the stimuli were presented as their original diagnostically coloured version, followed by their greyscale version, and lastly by their nondiagostically coloured version. These effects were mirrored in the early (i.e., 150 ms following stimulus onset) ERP frontal correlates. Their onset was delayed for greyscale scenes compared to diagnostically coloured scenes, and for nondiagnostically coloured scenes compared to the other two conditions. Frontal ERP amplitudes also decreased for greyscale and nondiagnostically coloured scenes. Together, the results suggest that diagnostic colours are part of the scene gist responsible for express scene categorization.     

Socio-demographic and psychopathological risk factors in obsessive-compulsive disorder: Epidemiologic study of school population

We assessed the presence of emotional disorders (obsessive-compulsive, anxiety and depressive) in 1,514 Spanish non-referred children (8–12 years old) to investigate the predictive ability of psychopathological and socio-demographic characteristics, and identify which of these were possible correlates for clinical obsessive-compulsive disorder (OCD) and subclinical OCD. At one year later, 562 subjects (risk group and without risk group) were re-assessed and we established the OCD diagnoses or the subclinical OCD diagnoses. We found that 20 participants presented clinical OCD and 46 participants presented subclinical OCD. Somatic and separation anxiety symptomatology were good predictors for clinical OCD, and obsessive concern was a predictor for subclinical OCD. Clinical OCD was associated with order/checking/pollution symptoms and with a lower socioeconomic status (SES). Subclinical OCD was associated with hyperactive and impulsive manifestations, obsessive concern, and superstition/mental compulsion. An early detection and the follow-up of anxiety or obsessive symptoms in children may be important for preventing the course of OCD.     

Obstacle Crossing Differences Between Blind and Blindfolded Subjects After Haptic Exploration

Little is known about the ability of blind people to cross obstacles after they have explored haptically their size and position. Long-term absence of vision may affect spatial cognition in the blind while their extensive experience with the use of haptic information for guidance may lead to compensation strategies. Seven blind and 7 sighted participants (with vision available and blindfolded) walked along a flat pathway and crossed an obstacle after a haptic exploration. Blind and blindfolded subjects used different strategies to cross the obstacle. After the first 20 trials the blindfolded subjects reduced the distance between the foot and the obstacle at the toe-off instant, while the blind behaved as the subjects with full vision. Blind and blindfolded participants showed larger foot clearance than participants with vision. At foot landing the hip was more behind the foot in the blindfolded condition, while there were no differences between the blind and the vision conditions. For several parameters of the obstacle crossing task, blind people were more similar to subjects with full vision indicating that the blind subjects were able to compensate for the lack of vision.