The survival processing effect in episodic memory in older adults and stroke patients.

In the present study, we tested whether processing information in the context of an ancestral survival scenario enhances episodic memory performance in older adults and in stroke patients. In an online study (Experiment 1), healthy young and older adults rated words according to their relevance to an ancestral survival scenario, and subsequent free recall performance was compared to a pleasantness judgment task and a moving scenario task in a within-subject design. The typical survival processing effect was replicated: Recall rates were highest in the survival task, followed by the moving and the pleasantness judgment task. Although older adults showed overall lower recall rates, there was no evidence for differences between the age groups in the condition effects. Experiment 2 was conducted in a neurological rehabilitation clinic with a sample of patients who had suffered from a stroke within the past 5 months. On the group level, Experiment 2 revealed no significant difference in recall rates between the three conditions. However, when accounting for overall memory abilities and executive function, independently measured in standardized neuropsychological tests, patients showed a significant survival processing effect. Furthermore, only patients with high executive function scores benefitted from the scenario tasks, suggesting that intact executive function may be necessary for a mnemonic benefit. Taken together, our results support the idea that the survival processing task - a well-studied task in the field of experimental psychology - may be incorporated into a strategy to compensate for memory dysfunction.

LED-based light sources optimised for high colour rendition from an end users' perspective.

Light emitting diode (LED) technology is continuously developing, leading to the current transition from simple phosphor-converted LED lamps to LED lamps optimised for high colour rendition in residential lighting. To assess whether such optimised phosphor-converted LED lamps may fulfil the end users' needs better than simple phosphor-converted LED lamps we asked participants to rank two particular brands of phosphor-converted LED lamps optimised for high colour rendition, a typical simple phosphor-converted LED lamp and a halogen lamp for pleasantness, naturalness and purchase preference. The results of two experiments suggest that phosphor-converted LED lamps optimised for high colour rendition have the potential to outperform simple phosphor-converted LED lamps and even to measure up to traditional halogen lighting in terms of user preference. However, this is not the case for all phosphor-converted LED lamps optimised for high colour rendition. From the end users' perspective, unfortunately, it is currently difficult if not impossible to choose the LED light source that one would prefer most. Practitioner Summary: Considering innovations in LED technology, we assessed the potential of LED lamps optimised for high colour rendition to outperform their predecessors regarding user preference. In one of two conditions, these optimised LED lamps outperformed a simple phosphor-converted LED lamp and measured up to halogen lighting. Abbreviations: LED: light emitting diode; CCT: correlated colour temperature; CRI: colour rendering index; CIE: Commission Internationale de l'Éclairage; CRI Ra: CIE General Colour Rendering Index; K: kelvin; lx: lux; GFC: goodness of fit coefficient; BLED80: simple blue-pumped phosphor-converted LED with a CRI Ra of 80; BLED96: blue-pumped phosphor-converted LED optimised for high colour rendition with a CRI Ra of 96; VLED97: violet-pumped phosphor-converted LED optimised for high colour rendition with a CRI Ra of 97; R9: CIE Special Colour Rendering Index for red; ANSI: American National Standards Institute; IES: Illuminating Engineering Society; Rf: IES Fidelity Index; Rg: IES Gamut Index; CC: chromaticity coordinates.

A common type of commercially available LED light source allows for colour discrimination performance at a level comparable to halogen lighting.

As light sources based on light emitting diodes (LED) are increasingly used to replace classic tungsten-based light sources in household lighting applications, possible impairments of colour perception under those light sources due to a different spectral power distribution become a major concern. The Colour Rendering Index (CRI) which is the only measure available to the end user is controversial and does not represent a comprehensive measure of colour perception. Aspects of colour perception disregarded by the CRI such as colour discrimination have to be taken into account as well. Therefore, we evaluated colour discrimination performance under a commercially available phosphor-converted LED light source from a popular brand (OSRAM) in comparison to a classic tungsten-based halogen light source. Colour discrimination performance was not affected by the type of light source, indicating that the phosphor-converted LED light source enables colour discrimination performance comparable to that of halogen lighting despite being associated with a lower CRI. Practitioner summary: Considering the increasing use of energy efficient light sources, we compared colour discrimination under a common type of phosphor-converted LED and under traditional halogen lighting. Colour discrimination performance was comparable in both lighting conditions, indicating that the phosphor-converted LED can replace halogen lighting without sacrificing colour discrimination for energy efficiency. Abbreviations: LED: light emitting diode; CRI: colour rendering index; CCT: correlated colour temperature; CIE: commission internationale de l'éclairage; FMHT: Farnsworth-Munsell 100-Hue Test; lm: lumen; lx: lux, lumen/m^2; W: watt; nm: nanometer; K: kelvin.

Subliminal stimuli modulate somatosensory perception rhythmically and provide evidence for discrete perception.

Despite being experienced as continuous, there is an ongoing debate if perception is an intrinsically discrete process, with incoming sensory information treated as a succession of single perceptual cycles. Here, we provide causal evidence that somatosensory perception is composed of discrete perceptual cycles. We used in humans an electrotactile temporal discrimination task preceded by a subliminal (i.e., below perceptual threshold) stimulus. Although not consciously perceived, subliminal stimuli are known to elicit neuronal activity in early sensory areas and modulate the phase of ongoing neuronal oscillations. We hypothesized that the subliminal stimulus indirectly, but systematically modulates the ongoing oscillatory phase in S1, thereby rhythmically shaping perception. The present results confirm that, without being consciously perceived, the subliminal stimulus critically influenced perception in the discrimination task. Importantly, perception was modulated rhythmically, in cycles corresponding to the beta-band (13-18 Hz). This can be compellingly explained by a model of discrete perceptual cycles.