Priming the mental time line

Growing experimental evidence suggests that temporal events are represented on a mental time line, spatially oriented from left to right. Support for the spatial representation of time comes mostly from studies that have used spatially organized responses. Moreover, many of these studies did not avoid possible confounds attributable to target stimuli that simultaneously convey both spatial and temporal dimensions. Here we show that task-irrelevant, lateralized visuospatial primes affect auditory duration judgments. Responses to short durations were faster when the auditory target was paired with left- than with right-sided primes, whereas responses to long durations were faster when paired with right- than with left-sided primes. Thus, when the representations of physical space and time are concurrently activated, physical space may influence time even when a lateralized, spatially encoded response is not required by the task. The time-space interaction reported here cannot be ascribed to any Spatial-Temporal Association of Response Codes effect. It supports the hypothesis that the representation of time is spatially organized, with short durations represented on the left space and longer ones on the right.     

Pure left neglect for Arabic numerals

Arabic numerals are diffused and language-free representations of number magnitude. To be effectively processed, the digits composing Arabic numerals must be spatially arranged along a left-to-right axis. We studied one patient (AK) to show that left neglect, after right hemisphere damage, can selectively impair the computation of the spatial frames underpinning recognition and understanding of Arabic numerals, without impairing the spatial frames for coding alphabetic strings or for coding environmental spatial information. The presence in our brain of these specific and precise spatial frames must be rooted in the paramount importance of Arabic numerals processing in our everyday activities.     

Naturally together: pitch-height and brightness as coupled factors for eliciting the SMARC effect in non-musicians

Psychological Research - Pitch-height is often labeled spatially (i.e., low or high) as a function of the fundamental frequency of the tone. This correspondence is highlighted by the so-called...     

Larger,smaller, odd or even? Task-specific effects of optokinetic stimulation on the mental number space

Previous studies have shown that number processing can induce spatial biases in perception and action and can trigger the orienting of visuospatial attention. Few studies, however, have investigated how spatial processing and visuospatial attention influences number processing. In the present study, we used the optokinetic stimulation (OKS) technique to trigger eye movements and thus overt orienting of visuospatial attention. Participants were asked to stare at OKS, while performing parity judgements (Experiment 1) or number comparison (Experiment 2), two numerical tasks that differ in terms of demands on magnitude processing. Numerical stimuli were acoustically presented, and participants responded orally. We examined the effects of OKS direction (leftward or rightward) on number processing. The results showed that rightward OKS abolished the classic number size effect (i.e., faster reaction times for small than large numbers) in the comparison task, whereas the parity task was unaffected by OKS direction. The effect of OKS highlights a link between visuospatial orienting and processing of number magnitude that is complementary to the more established link between numerical and visuospatial processing. We suggest that the bidirectional link between numbers and space is embodied in the mechanisms subserving sensorimotor transformations for the control of eye movements and spatial attention.     

Experimental Evidence From Newborn Chicks Enriches Our Knowledge on Human Spatial–Numerical Associations

Núñez and Fias raised concerns on whether our results demonstrate a linear number‐space mapping. Patro and Nuerk urge caution on the use of animal models to understand the origin (cultural vs. biological) of the orientation of spatial–numerical association. Here, we discuss why both objections are unfounded.     

How tool use and arm position affect peripersonal space representation

Experiment 1 investigated whether tool use can expand the peripersonal space into the very far extrapersonal space. Healthy participants performed line bisection in peripersonal and extrapersonal space using wooden sticks up to a maximum of 240 cm. Participants misbisected to the left of the true midpoint, both for lines presented in peripersonal and for those presented in extrapersonal space, confirming a peripersonal space expansion up to a distance of 240 cm. Experiment 2 investigated whether arm position could influence the perception of peripersonal and extrapersonal space during tool use. Participants performed line bisection in the peripersonal and in the extrapersonal space (up to a maximum of 120 cm) using wooden sticks in two different conditions: either with the arm bent or with the arm stretched. Results showed stronger pseudoneglect in the stretched arm condition.     

Extra‐powerful on the visuo‐perceptual space,but variable on the number space: Different effects of optokinetic stimulation in neglect patients

We studied the effects of optokinetic stimulation (OKS; leftward, rightward, control) on the visuo‐perceptual and number space, in the same sample, during line bisection and mental number interval bisection tasks. To this end, we tested six patients with right‐hemisphere damage and neglect, six patients with right‐hemisphere damage but without neglect, and six neurologically healthy participants. In patients with neglect, we found a strong effect of leftward OKS on line bisection, but not on mental number interval bisection. We suggest that OKS influences the number space only under specific conditions.