The Virtual Kitchen Challenge: preliminary data from a novel virtual reality test of mild difficulties in everyday functioning

ABSTRACT

Background: Efficient, objective measures of mild functional difficulties are lacking. Preliminary data from a novel, non-immersive virtual reality, performance-based task (Virtual Kitchen Challenge; VKC) were obtained to address this gap.

Methods: 14 older and 21 younger adults completed cognitive tests and two everyday tasks (breakfast, lunch) in the VKC with virtual objects and a touch-screen and in the Real Kitchen with real objects (order counterbalanced). Automated performance measures were obtained from the VKC program and human coders scored VKC and Real Kitchen videos for errors.

Results: Older adults made more errors than younger adults on the VKC and Real Kitchen, with similar error patterns across measures. VKC automated measures were significantly related to measures from human coders, performance on the Real Kitchen, and cognitive test scores.

Conclusion: The VKC is a valid and highly efficient performance-based measure of subtle functional difficulties with great potential for future clinical and research applications.     

The effect of hydrogen plasma on the properties of a-Si:H/a-Si1-xNx:H superlattices

Abstract

A hydrogen plasma introduced during the interrupting interval when alternating two gases affects the properties of a-Si:H/a-Si_1-xN_x:H superlattices resulting in the creation of fewer interface defects than the superlattices prepared without the hydrogen plasma.     

Two‐ to three‐month‐old infants prefer moving face patterns to moving top‐heavy patterns

Newborn infants prefer face‐like patterns over non‐face‐like patterns. This preference is explained by newborns' preference for a “top‐heavy” configuration, that is, for geometric patterns that have more elements in the upper part than in the lower part of the configuration (Simion, Valenza, Macchi Cassia, Turati, & Umiltà, 2002). However, for 3‐month‐old infants, face preference cannot be explained only by a preference for “top‐heaviness” because they prefer veridical face images over top‐heavy images. The present study used geometric patterns to investigate whether 2‐ to 3‐month‐old infants' preference for face patterns exceeds their preference for top‐heavy configurations. In Experiment 1, we revealed that the infants preferred the face pattern to the top‐heavy pattern only when the internal elements of the patterns were presented with face‐like movements. This facilitative effect of internal movement was observed again in Experiment 2, in which the patterns were presented with non‐face‐like movements. These results suggest that 2‐ to 3‐month‐olds' preference for geometric face patterns is greater than their preference for top‐heavy patterns only when aided by the movement of internal elements.     

Chemical ordering of Co and Ni in a W-(AlCoNi) crystalline approximant related to Al–Co–Ni decagonal quasicrystals studied by atomic resolution energy-dispersive X-ray spectroscopy

A W-(AlCoNi) crystalline approximant, which is closely related to Al–Co–Ni decagonal quasicrystals, in an Al_72.5Co₂₀Ni_7.5 alloy has been studied by atomic resolution energy-dispersive X-ray spectroscopy (EDS), in an instrument attached to a spherical aberration (Cs)-corrected scanning transmission electron microscope. On high-resolution EDS maps of Co and Ni elements, obtained by integrating many sets of EDS data taken from undamaged areas, chemical ordering of Co and Ni is clearly detected. In the structure of the W-(AlCoNi) phase, consisting of arrangements of transition-metal (TM) atoms located at vertices of pentagonal tilings and pentagonal arrangements of mixed sites (MSs) of TM and Al atoms, Co atoms occupy the TM atom positions with the pentagonal tiling and Ni is enriched in part of the pentagonal arrangements of MSs.     

Young children produce categorical false recall without activation of the lure items

Individuals who study a list of words that are all related to another word that is not presented (a lure word) sometimes produce a false memory of having studied the lure word. The false memories are observed in lists of words that are in the same category as (category list) or associated with (associative list) a word that was not presented in an attempt to elicit false recall. The present study investigated whether young children create these types of false recall. Following the study of a categorical list, false recall was elicited in young children to the same degree as in adults, but studying an associative list elicited false recall only in adults. Furthermore, categorically related lure words did not have a priming effect in young children. These results suggest that the categorical false recall is produced via a different mechanism from the associative false recall.     

Estimating averages from distributions of tone durations

We examined whether estimating average duration was influenced by the distribution peak location. We presented participants with samples of various tone durations and then presented comparison tone durations. Participants judged whether each comparison duration was longer than the average sample duration. Estimates of the averages were inferred from the psychophysical functions. The durations were sampled from three distributions: one positively skewed, one symmetric, and one negatively skewed. In Experiment 1, every participant was presented with every distribution. Estimates of the averages were unbiased for the symmetric distribution but were biased toward the long tail of each skewed distribution. This would occur if participants combined the sample to be judged with the previous, irrelevant samples, or with the comparison durations. In Experiment 2, each participant was presented with samples from only one of the distributions. Estimates of the averages were still biased toward the long tails of the skewed distributions. This would occur if participants combined the sample to be judged with the comparison durations, which were the same for the three distributions. In Experiment 3, each participant was presented with only one distribution, and each distribution was tested with its own comparison durations, selected as percentiles from the distribution. The estimates were accurate for the smallest population mean (positively skewed distribution) but underestimated the larger means. These results could be explained by subjective shortening of the durations in memory, with a simple equation from scalar timing theory. This equation correctly predicted two results: The estimated averages were a linear function of the stimulus means, and the variances were a linear function of the squared stimulus means. Neither prediction was dependent on the skewness of the stimulus durations.     

The movement of internal facial features elicits 7 to 8‐month‐old infants' preference for face patterns

A preference for static face patterns is observed in newborns and disappears around 3 months after birth. A previous study has demonstrated that 5‐month‐old infants prefer schematic faces only when the internal features are moving, suggesting that face‐specific movement enhances infants' preference. The present study investigates the facilitative effect of the movement of internal facial features on infants' preference. To examine infants' preference, we used animated face patterns consisting of a head‐shaped contour and three disk blobs. The inner blobs expanded and contracted to represent the opening and closing of the eyes and mouth, and were constrained to open and close only in a biologically possible vertical direction resembling the facial muscle structure. We compared infants' preferential looking time for this vertically moving (VM) face pattern with their looking time for a horizontally moving (HM) face pattern in which blobs transformed at the same speed in a biologically impossible, horizontal direction. In Experiment 1, 7 to 8‐month‐olds preferred the VM to the HM, but 5 to 6‐month‐olds did not. However, the preference was diminished in both cases when the moving face patterns were presented without contour (Experiment 2). Our results suggest that internal facial features with vertical movements promote face preference in 7 to 8‐month‐olds. Copyright © 2011 John Wiley & Sons, Ltd.     

Perception of Mooney faces by young infants: the role of local feature visibility, contrast polarity, and motion

We examined the ability of young infants (3- and 4-month-olds) to detect faces in the two-tone images often referred to as Mooney faces. In Experiment 1, this performance was examined in conditions of high and low visibility of local features and with either the presence or absence of the outer head contour. We found that regardless of the presence of the outer head contour, infants preferred upright over inverted two-tone face images only when local features were highly visible (Experiment 1a). We showed that this upright preference disappeared when the contrast polarity of two-tone images was reversed (Experiment 1b), reflecting operation of face-specific mechanisms. In Experiment 2, we investigated whether motion affects infants' perception of faces in Mooney faces. We found that when the faces appeared to be rigidly moving, infants did show an upright preference in conditions of low visibility of local features (Experiment 2a). Again the preference disappeared when the contrast polarity of the image was reversed (Experiment 2b). Together, these results suggest that young infants have the ability to integrate fragmented image features to perceive faces from two-tone face images, especially if they are moving. This suggests that an interaction between motion and form rather than a purely motion-based process (e.g., structure from motion) facilitates infants' perception of faces in ambiguous two-tone images.     

Visual discrimination in an orangutan (Pongo pygmaeus): measuring visual preference

Although previous studies have confirmed that trained orangutans visually discriminate between mammals and artificial objects, whether orangutans without operant conditioning can discriminate remains unknown. The visual discrimination ability in an orangutan (Pongo pygmaeus) with no experience in operant learning was examined using measures of visual preference. Sixteen color photographs of inanimate objects and of mammals with four legs were randomly presented to an orangutan. The results showed that the mean looking time at photographs of mammals with four legs was longer than that for inanimate objects, suggesting that the orangutan discriminated mammals with four legs from inanimate objects. The results implied that orangutans who have not experienced operant conditioning may possess the ability to discriminate visually.