Name: methods for presenting real-world objects under controlled laboratory conditions
Uploaded: 2019-06-21T14:30:00.000+00:00
Duration: 6 min 54 s
Description: Watch this Scientific Journal Video about Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions at JoVE.com

This work was supported by grants to J.C. Snow from the National Eye Institute of the National Institutes of Health (NIH) under Award Number R01EY026701, the National Science Foundation (NSF) [grant 1632849] and the Clinical Translational Research Infrastructure Network [grant 17-746Q-UNR-PG53-00]. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH, NSF or CTR-IN.

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The authors have nothing to disclose.

The overarching goal of the current paper is to facilitate future studies of &#39;real world&#39;&#160;object vision by providing detailed information about how to present large numbers of real-world objects (and images) under controlled experimental conditions. We present an ecologically-valid approach for studying the factors that influence dietary choice and food valuation. We describe methods employed in a recent study of human decision-making7 in which we examined whether snack foods presented in the form of real-world objects are valued differently to foods presented as 2-D images. In our experiment7, hungry college students placed monetary bids on a range of everyday snack foods. Using a within-subjects design, half of the stimuli were presented to each observer as real foods and the remainder were presented as high-resolution colored 2-D photographs of foods. The real foods and food images were matched closely for apparent size, distance, background, viewpoint, and illumination. In an important departure from previous studies7, environmental conditions and stimulus timing were identical across the different display formats. The order of trials in each display format was randomized throughout the experiment using a custom-built turntable device. At the start of the testing session, participants rated their preference for, and familiarity with, sixty different appetitive snack foods (presented as images). In the main experiment, observers indicated their willingness-to-pay (WTP) for each of the sixty foods which were displayed either as real objects or 2-D images. Assignment of food items to the real object or image conditions was counterbalanced across observers. Following from an earlier study that addressed a similar question12, we measured WTP using a Becker DeGroot Marschak (BDM)35 bidding task in which observers entered a monetary bid ($0-$3) for each snack food to &#8216;win&#8217; the opportunity to consume a food at the end of the experiment. Given the nested structure of the data, we used linear mixed effects modeling to determine the extent to which WTP was influenced by display format, food preference, caloric content, and estimated calories. We found that observers were willing to pay 6.62% more for foods displayed as real objects versus food images7. The amplification in value for real food displays was consistent across all levels of food preference, as well as across actual and estimated caloric content of the foods. These results are surprising because participants knew that they could receive the same (real) snack food reward at the end of the experiment regardless of the format in which the food was presented during the bidding task. Importantly, the findings confirm that there is a reliable &#39;real-food exposure effect&#39;&#160;on willingness-to-pay7,12 that cannot be accounted for by differences in environmental context, stimulus presentation method, or trial timing&#160;across display formats.
In summary, we have provided detailed methods that describe how to prepare real object stimuli and closely-matched 2-D computerized images of the same items, as well as methods for creating a manually-operated turntable for presenting large numbers of real objects and images in interleaved succession. We provided instructions for controlling stimulus presentation and viewing time across all trials, for example, by using computer-controlled display glasses. The methods presented here open up new avenues to examine the underlying mechanisms for the observed effects. For example, future studies could assess directly the impact of stereopsis by presenting real-world stimuli under monocular viewing conditions (which could, for example, be tested easily using monocular vs. binocular states of the computer-controlled glasses described here). This would form a nice comparison with the image-based trials in which both motion parallax and stereopsis provide conflicting depth information.
Although we have offered practical solutions for presenting real-world objects under controlled viewing conditions, working with real objects in the laboratory is undeniably challenging, costly, and time-consuming. In addition to the technicalities associated with controlling stimulus parameters such as illumination, position, size and timing, collection and careful preparation (i.e. mounting) of real object stimuli can be painstakingly slow compared to the time that would be required to prepare images alone. The experimenter(s) must be well-practiced with locating the correct exemplars prior to each trial within required time limits and there are obvious possibilities for experimenter error. In some cases where trial numbers are limited, such as in fMRI8,39 and patient10 studies of real-object vision, we use a video camera to record which exemplars were presented on each trial and the recordings are cross-checked post-hoc for accuracy. There are additional challenges with working with foods, which are perhaps a unique class of real object stimuli. Depending on the number of items used in the study, a relatively large selection of foods must be kept fresh, on-hand, and in relatively close proximity to the testing room. In decision-making paradigms involving foods, the stimuli are typically shown with the packaging opened and some of the contents visible. Although many manufactured foods seem to have an indefinite shelf life (i.e., the Twinkie) most items need to be replaced regularly to maintain freshness and visual appeal. Together, these conditions make it difficult to control exactly the appearance of the foods between real and image formats to the degree that we have found is possible with non-perishable stimulus classes, such as objects and tools. It is also important to note that we modified our turntable apparatus from the way it appeared in the original study7 (black) to the way it is depicted here (white) because we found that the white apparatus was easier to clean and stimulus contrast was improved.
The above considerations raise the critical question of whether or not the time and resource costs of working with real objects are justified, or whether similar results can be obtained using more convenient image displays. The results from our decision-making paradigm7 indicate that real food displays elicit a constant increase in valuation (i.e., a linear effect) that does not interact with other factors such as preference or caloric density. These results from decision-making dovetail with findings from other domains of human cognition. For example, real-world objects are more easily recognized10,40,41, enhance memory42, and capture attention43,44 more so than images do. Compared to 2-D images, fMRI repetition suppression effects are reduced for real objects8. Similarly, fine-grained examination of the temporal dynamics of brain responses to real objects as measured by high-density EEG reveals that real objects&#160; (vs. images) elicit stronger and more prolonged desynchronization of the mu rhythm -a signature of activation in visuo-motor networks involved in automatic planning of motor actions9. The amplification in mu desynchronization for real objects is independent of early signal differences related to stereopsis9. Taken together, these findings suggest that the pattern of results that could be obtained using image displays may be broadly consistent, but just less compelling, than what might otherwise have been observed had real-world objects been used. In other words, if findings from studies of image vision transfer predictably to real object vision, then the translational value of basic research studies of image vision is preserved. Although there is currently insufficient data to make firm conclusions on this issue, recent evidence for dissociations in the effects of real objects across motor areas in the left versus right hemispheres9 and across egocentric distances6 raise concerns about this assumption. For example, the effect of real objects on attentional capture fall to the levels observed for 2-D and 3-D images when the objects are positioned outside of reach of the observer, or when they are within reach but behind a transparent barrier6, suggesting that the potential for manual interaction with a real object (but not an image) determines how it is processed. Future studies could use the protocols described here to investigate whether similar underlying causal mechanisms modulate &#8216;real-food exposure effects&#39;&#160;on willingness-to-pay. For example, a distance or barrier manipulation6 could be employed to determine whether real snack foods that are reachable or graspable are processed differently to those that are not (and to determine whether the same manipulation has any effect on processing of food images). Future studies using ecologically-valid real-object stimuli are required to make definitive conclusions on this issue. Importantly, it may not be the case that similar mechanisms are at play in different cognitive domains, or in different tasks. Nevertheless, our approach to working with real-world objects promises to provide important new insights into the underlying processes and mechanisms that drive naturalistic vision.

The translational value of primary research in human perception and cognition hinges on the extent to which the findings transfer to real-world stimuli and contexts. A long-standing question concerns how the brain processes real-world sensory inputs. Currently, knowledge of visual cognition is based almost exclusively on studies that have relied on stimuli in the form of two-dimensional (2-D) pictures, usually presented in the form of computerized images. Although image interaction is becoming increasingly common in the modern world, humans are active observers for whom the visual system has evolved to allow perception and interaction with real objects, not images1. To date, the overarching assumption in studies of human vision has been that images are equivalent to, and appropriate proxies for, real object displays. Currently, however, we know surprisingly little about whether images effectively trigger the same underlying cognitive processes as do the real objects. Therefore, it is important to determine the extent to which responses to images are like, or different from, those elicited by their real-world counterparts.
There are several important differences between real objects and images that could lead to differences in how these stimuli are processed in the brain. When we look at real objects with two eyes, each eye receives information from a slightly different horizontal vantage point. This discrepancy between the different images, known as binocular disparity, is resolved by the brain to produce a unitary sense of depth2,3. Depth cues derived from stereoscopic vision, together with other sources such as motion parallax, convey precise information to the observer about the object&#8217;s egocentric distance, location, and physical size, as well its three-dimensional (3-D) geometric shape structure4,5. Planar images of objects do not convey information about the physical size of the stimulus because only the distance to the monitor is known by the observer, not the distance to the object. While 3-D images of objects, such as stereograms, approximate more closely the visual appearance of real objects, they do not exist in 3-D space, nor do they afford genuine motor actions such as grasping with the hands6.
The practical challenges of using real object stimuli in experimental contexts 
Unlike studies of the image vision in which stimulus presentation is entirely computer-controlled, working with real objects presents a range of practical challenges for the experimenter. The position, order, and timing of object presentations must be controlled manually throughout the experiment. Working with real objects (unlike images) can involve a significant time commitment due to the need to collect7,8,9 or make10 the objects, set up the stimuli prior to the experiment, and present the objects manually during the study. Moreover, in experiments that are designed to compare, directly, responses to real objects with images, it is critical to match closely the appearance of the stimuli in the different display formats8,9. Stimulus parameters, environmental conditions, as well as randomization and counterbalancing of real object and image stimuli, must all be controlled carefully to isolate causal factors and rule out alternative explanations for the observed effects.
The methods detailed below for presenting real objects (and matched images) are described in the context of a decision-making paradigm. The general approach can be extended, however, to examine whether stimulus format influences other aspects of visual cognition such as perception, memory or attention.
Are real objects processed differently to images? A case example from decision-making 
The mismatch between the kinds of objects that we encounter in real-world scenarios versus those examined in laboratory experiments is especially apparent in studies of human decision-making. In most studies of dietary choice, participants are asked to make judgments about snack foods that are presented as colored 2-D images on a computer monitor 11,12,13,14. In contrast, everyday decisions about which foods to eat are usually made in the presence of real foods, such as at the supermarket or the cafeteria. Although in modern life we regularly view images of snack foods (i.e., on billboards, television screens and online platforms), the ability to detect and respond appropriately to the presence of real energy-dense foods may be adaptive from an evolutionary perspective because it facilitates growth, competitive advantage, and reproduction15,16,17.
Research outcomes in scientific studies of decision-making and dietary choice have been used to guide public health initiatives aimed at curbing rising obesity rates. Unfortunately, however, these initiatives appear to have met with little to no measurable success18,19,20,21. Obesity remains a major contributor to the global burden of a disease22 and is linked to a range of associated health problems, including coronary heart disease, dementia, Type II diabetes, certain cancers, and increased overall risk of morbidity22,23,24,25,26,27. The sharp rise in obesity and associated health conditions over recent decades28 has been linked with the availability of cheap, energy-dense foods18,29. As such, there is an intense scientific interest in understanding the underlying cognitive and neural systems that regulate everyday dietary decisions.
If there are differences in the way foods in different formats are processed in the brain, then this might provide insights into why public health approaches to combating obesity have been unsuccessful. Despite the differences between images and real-world objects, described above, surprisingly little is known about whether images of snack foods are processed similarly to their real-world counterparts. In particular, little is known about whether or not real foods are perceived to be more valuable or satiating than matched images of the same items. Classic early behavioral studies found that young children were able to delay gratification in the context of 2-D colored images of snack foods30, but not when they were confronted with real snack foods31. However, few studies have examined in adults whether the format in which a snack food is displayed influences decision-making or valuation12,32,33 and only one study to date, from our laboratory, has tested this question when stimulus parameters and environmental factors are matched across formats7. Here, we describe innovative techniques and apparatus for investigating whether decision-making in healthy human observers is influenced by the format in which the stimuli are displayed.
Our study7 was motivated by a previous experiment conducted by Bushong and colleagues12 in which college-aged students were asked to place monetary bids on a range of everyday snack foods using a Becker-DeGroot-Marschak (BDM) bidding task34. Using a between-subjects design, Bushong and colleagues12 presented the snack foods in one of three formats: text descriptors (i.e., &#39;Snickers bar&#39;), 2-D colored images, or real foods. Average bids for the snacks (in dollars) were contrasted across the three participant groups. Surprisingly, students who viewed real foods were willing to pay 61% more for the items than those who viewed the same stimuli as images or text descriptors -a phenomenon the authors termed the &#39;real-exposure effect&#39;12. Critically, however, participants in the text and image conditions completed the bidding task in a group setting and entered their responses via individual computer terminals; conversely, those assigned to the real food condition performed the task one-on-one with the experimenter. The appearance of the stimuli in the real and image conditions was also different. In the real food condition, the foods were presented to the observer on a silver tray, whereas in the image condition the stimuli were presented as scaled cropped images on a black background. Thus, it is possible that participant differences, environmental conditions, or stimulus-related differences, could have led to inflated bids for the real foods. Following from Bushong, et al.12, we examined whether the real foods are valued more than 2-D images of food, but critically, we used a within-subjects design in which environmental and stimulus-related factors were carefully controlled. We developed a custom-designed turntable in which the stimuli in each display format could be interleaved randomly from trial to trial. Stimulus presentation and timing were identical across the real object and image trials, thus reducing the likelihood that participants could use different strategies to perform the task in the different display conditions. Finally, we controlled carefully the appearance of the stimuli in the real object and image conditions so that the real foods and images were matched closely for apparent size, distance, viewpoint, and background. There are likely to be other procedures or mechanisms that could allow for randomizing stimulus formats across trials, but our method allows for many objects (and images) to be presented in relatively rapid interleaved succession. From a statistical standpoint, this design maximizes power to detect significant effects more so than is possible using between-subjects designs. Similarly, the effects cannot be attributed to a-priori differences in willingness-to-pay (WTP) between observers. It is, of course, the case that in within-subjects designs open the possibility for demand characteristics. However, in our study participants understood that they could &#39;win&#39;&#160;a food item at the end of the experiment regardless of the display format in which it appeared in the bidding task. Participants were also informed that arbitrarily reducing bids (i.e., for the images) would reduce their chances of winning and that the best strategy for winning the desired item is to bid one&#8217;s true value34,35,36. The aim of this experiment is to compare WTP for real foods versus 2-D images using a BDM bidding task34,35.

<table><tbody><tr><td>EOS Rebel T2i Body Camera</td><td>Canon&amp;nbsp;</td><td>4462B001</td><td></td></tr><tr><td>MATLAB</td><td>MathWorks&amp;nbsp;</td><td>R2017b</td><td>Computer programming software. Download this additional free toolbox: PsychToolbox 3.0.14</td></tr><tr><td>Photoshop</td><td>Adobe</td><td>CS6</td><td></td></tr><tr><td>PLATO Visual Occlusion Glasses</td><td>Translucent Technologies Inc.&amp;nbsp;</td><td>N/A</td><td></td></tr><tr><td>SPSS</td><td>IBM</td><td>Version 22</td><td>Statitical analysis software</td></tr><tr><td>ToTaL Control System (USB)</td><td>Translucent Technologies Inc.&amp;nbsp;</td><td>N/A</td><td>The ToTaL Control System&amp;nbsp; controls the&amp;nbsp;PLATO&amp;nbsp;spectacles</td></tr></tbody></table>

methods for presenting real-world objects under controlled laboratory conditions

Our knowledge of human object vision is based almost exclusively on studies in which the stimuli are presented in the form of computerized two-dimensional (2-D) images. In everyday life, however, humans interact predominantly with real-world solid objects, not images. Currently, we know very little about whether images of objects trigger similar behavioral or neural processes as do real-world exemplars. Here, we present methods for bringing the real-world into the laboratory. We detail methods for presenting rich, ecologically-valid real-world stimuli under tightly-controlled viewing conditions. We describe how to match closely the visual appearance of real objects and their images, as well as novel apparatus and protocols that can be used to present real objects and computerized images on successively interleaved trials. We use a decision-making paradigm as a case example in which we compare willingness-to-pay (WTP) for real snack foods versus 2-D images of the same items. We show that WTP increases by 6.6% for food items displayed as real objects versus high-resolution 2-D colored&#160;images of the same foods -suggesting that real foods are perceived as being more valuable than their images. Although presenting real object stimuli under controlled conditions presents several practical challenges for the experimenter, this approach will fundamentally expand our understanding of the cognitive and neural processes that underlie naturalistic vision.

Representative results from this experiment are presented below. A more detailed description of the results, together with a follow-up study, can be found in the original publication7. We used a linear mixed effects model with the dependent variable of Bid, and independent variables of Display Format, Preference, Caloric Density, and Estimated Calories. As expected, and in line with previous studies12,14, there was a strong positive relationship between Preference ratings and Bids (F(1,1655) = 1803.69, p &#60; .001) such that a one unit increase in Preference was associated with an increase of $0.15 in Bid value (&#946; = .15, t(1655) = 42.47, p &#60; .001; d = 8.03). There was also a significant main effect of Caloric Density on Bids (F(1, 1649) = 6.87, p &#60; .01). A one unit increase in Caloric Density was associated with an increase of $.024 in Bids (&#946; = .024, t(1649) = 2.62, p &#60; .01; d = 0.50). The main effect of Estimated Calories was also significant (F(1, 1672) = 6.88, p &#60; .01)11. A one unit increase in Estimated Calories was associated with an increase of $.009 in WTP (&#946; = .009, t(1671) = 2.62, p &#60; .01; d = .50). In other words, observers rated foods that were perceived to be of greater caloric content to be more valuable than foods of lower caloric content. Critically, after controlling for all other factors, we found a significant main effect of Display Format (F(1, 1645) = 7.99, p &#60; .01, d = .53) in which there was a 6.62% increase in Bids for real foods versus food images. The amplification in WTP for real foods (vs. images) was relatively consistent across participants, with 20 out of 28 participants showing the effect. For illustrative purposes, Figure 5 displays average Bid values for each snack food item as a function of Preference, separately for foods shown as real objects (red) and images (blue). Similarly, Figure 6 displays average Bid values for each snack food as a function of Caloric Density, separately for foods in each Display Format. The amplification in WTP for real foods vs. images is evident in both Figure 5 and Figure 6. Importantly, the effect of Display Format on bids was constant across food Preference (F(1, 1644) = .025, p = .88), Caloric Density (F(1, 1643) = 2.54, p = .11) and Estimated Calories (F(1,1643) = .11, p = .74), and there were no significant higher-order interactions between any other factors (all p-values &#8805; .11).
Although we observed an effect of estimated calories on Bids, the effect was relatively weak. This result may be explained by the fact that participants performed the estimation task in response to text prompts after the main experiment, rather than while looking at the foods at the time of stimulus presentation. Furthermore, estimating the number of calories in a given food item is not necessarily an intuitive task; many observers are unaware (or do not pay attention to) the caloric density of the foods they consume.
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/59762/59762fig5.jpg" /> 
Figure 5: Average monetary bids for each snack food plotted as a function of preference and display format. As expected, there was a strong positive relationship between monetary bids and food preference ratings, with higher bids for foods that were more strongly liked. Importantly, there was a significant main effect of Display Format in which bids for real foods were greater than matched food images. There was no significant interaction between the effect of display format and preference. Mean bid values ($) for the foods are displayed separately for the real foods (red) and 2-D images (blue). Each data point represents the group average bid for each food item, separately for foods in each display format. Solid red and blue lines represent lines of best fit for the real object and image conditions, respectively. This figure has been reprinted from from reference7 with permission from Elsevier. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59762/59762fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/59762/59762fig6.jpg" /> 
Figure 6: Average monetary bids for each snack food plotted as a function of caloric density and display format. We found a significant positive relationship between bids and actual caloric density, with higher bids for foods of higher caloric density. There was no significant interaction between the effect of display format and caloric density. Mean bid values ($) for the foods are displayed separately for the real foods (red) and 2-D images (blue). Each data point represents the group average bid for each food item, separately for foods in each display format. Solid red and blue lines represent lines of best fit for the real object and image conditions, respectively. This figure has been reprinted from from reference7 with permission from Elsevier. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/59762/59762fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions at JoVE.com

Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions

We describe methods for presenting real-world objects and matched images of the same objects under tightly-controlled experimental conditions. The methods are described in the context of a decision-making task, but the same real-world approach can be extended to other cognitive domains such as perception, attention, and memory.

Our knowledge of human object vision is based almost exclusively on studies in which the stimuli are presented in the form of computerized two-dimensional ...

methods-for-presenting-real-world-objects-under-controlled-laboratory

Nanyang Technological University

Research

JoVE Journal

Behavior

5.9K Views.  University of Nevada, Reno. We describe methods for presenting real-world objects and matched images of the same objects under tightly-controlled experimental conditions. The methods are described in the context of a decision-making task, but the same real-world approach can be extended to other cognitive domains such as perception, attention, and memory.

Video: Methods for Presenting Real-world Objects Under Controlled Laboratory Conditions

Using a Virtual Store As a Research Tool to Investigate Consumer In-store Behavior

People&#39;s responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various approaches (e.g., surveys or laboratory settings) to study in-store behaviors, but the external validity of these is limited by their poor capability to resemble realistic choice environments. In addition, building a real store to meet experimental conditions while controlling for undesirable effects is costly and highly difficult. A virtual store developed by virtual reality techniques potentially transcends these limitations by offering the simulation of a 3D virtual store environment in a realistic, flexible, and cost-efficient way. In particular, a virtual store interactively allows consumers (participants) to experience and interact with objects in a tightly controlled yet realistic setting. This paper presents the key elements of using a desktop virtual store to study in-store consumer behavior. Descriptions of the protocol steps to: 1) build the experimental store, 2) prepare the data management program, 3) run the virtual store experiment, and 4) organize and export data from the data management program are presented. The virtual store enables participants to navigate through the store, choose a product from alternatives, and select or return products. Moreover, consumer-related shopping behaviors (e.g., shopping time, walking speed, and number and type of products examined and bought) can also be collected. The protocol is illustrated with an example of a store layout experiment showing that shelf length and shelf orientation influence shopping- and movement-related behaviors. This demonstrates that the use of a virtual store facilitates the study of consumer responses. The virtual store can be especially helpful when examining factors that are costly or difficult to change in real life (e.g., overall store layout), products that are not presently available in the market, and routinized behaviors in familiar environments.

This paper describes the use of a desktop virtual store to create virtual shopping environments to investigate in-store consumer behavior. A description of the protocol to build and run experiments, example results from an experiment concerning store layout, and important considerations when conducting virtual store experiments are presented.

People&#39;s responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various ...

Creating Objects and Object Categories for Studying Perception and Perceptual Learning

In order to quantitatively study object perception, be it perception by biological systems or by machines, one needs to create objects and object categories with precisely definable, preferably naturalistic, properties1. Furthermore, for studies on perceptual learning, it is useful to create novel objects and object categories (or object classes) with such properties2.
Many innovative and useful methods currently exist for creating novel objects and object categories3-6 (also see refs. 7,8). However, generally speaking, the existing methods have three broad types of shortcomings.
First, shape variations are generally imposed by the experimenter5,9,10, and may therefore be different from the variability in natural categories, and optimized for a particular recognition algorithm. It would be desirable to have the variations arise independently of the externally imposed constraints.
Second, the existing methods have difficulty capturing the shape complexity of natural objects11-13. If the goal is to study natural object perception, it is desirable for objects and object categories to be naturalistic, so as to avoid possible confounds and special cases.
Third, it is generally hard to quantitatively measure the available information in the stimuli created by conventional methods. It would be desirable to create objects and object categories where the available information can be precisely measured and, where necessary, systematically manipulated (or 'tuned'). This allows one to formulate the underlying object recognition tasks in quantitative terms.
Here we describe a set of algorithms, or methods, that meet all three of the above criteria. Virtual morphogenesis (VM) creates novel, naturalistic virtual 3-D objects called 'digital embryos' by simulating the biological process of embryogenesis14. Virtual phylogenesis (VP) creates novel, naturalistic object categories by simulating the evolutionary process of natural selection9,12,13. Objects and object categories created by these simulations can be further manipulated by various morphing methods to generate systematic variations of shape characteristics15,16. The VP and morphing methods can also be applied, in principle, to novel virtual objects other than digital embryos, or to virtual versions of real-world objects9,13. Virtual objects created in this fashion can be rendered as visual images using a conventional graphical toolkit, with desired manipulations of surface texture, illumination, size, viewpoint and background. The virtual objects can also be 'printed' as haptic objects using a conventional 3-D prototyper.
We also describe some implementations of these computational algorithms to help illustrate the potential utility of the algorithms. It is important to distinguish the algorithms from their implementations. The implementations are demonstrations offered solely as a 'proof of principle' of the underlying algorithms. It is important to note that, in general, an implementation of a computational algorithm often has limitations that the algorithm itself does not have.
Together, these methods represent a set of powerful and flexible tools for studying object recognition and perceptual learning by biological and computational systems alike. With appropriate extensions, these methods may also prove useful in the study of morphogenesis and phylogenesis.

We describe a novel methodology for creating naturalistic 3-D objects and object categories with precisely defined feature variations. We use simulations of the biological processes of morphogenesis and phylogenesis to create novel, naturalistic virtual 3-D objects and object categories that can then be rendered as visual images or haptic objects.

In order to quantitatively study object perception, be it perception by biological systems or by machines, one needs to create objects and object ...

Neuroscience

Three Laboratory Procedures for Assessing Different Manifestations of Impulsivity in Rats

The present article provides a guide for the conduction and analysis of three conditioning-based protocols to evaluate impulsivity in rats. Impulsivity is a meaningful concept because it is associated with psychiatric conditions in humans and with maladaptive behavior in non-human animals. It is believed that impulsivity is composed of separate factors. There are laboratory protocols devised to assess each of these factors using standardized automated equipment. Delay discounting is associated with the incapacity to be motivated by delayed outcomes. This factor is evaluated through intertemporal choice protocols, which consist&#160;of presenting the individual with a choice situation involving an immediate reward and a larger but delayed reward. Response inhibition deficit is associated with the incapacity to withhold prepotent responses. Differential reinforcement of low rates (DLR) and feature-negative discrimination protocols assess the response inhibition deficit factor of impulsivity. The former imposes a condition to a motivated individual in which most wait a minimum period of time for a response to be rewarded. The latter evaluates the capacity of individuals to refrain from food seeking responses when a signal of the absence of food is presented. The purpose of these protocols is to construct an objective quantitative measure of impulsivity, which serves to make cross-species comparisons, allowing the possibility of translational research. The advantages of these particular protocols include their easy set-up and application, which stems from the relatively small amount of equipment needed and the automated nature of these protocols.

We present three protocols that assess different forms of impulsivity in rats and other small mammals. Intertemporal choice procedures evaluate the tendency to discount the value of delayed outcomes. Differential reinforcement of low rates and feature-negative discrimination evaluate response inhibition capacity with and without punishment for inappropriate responses, respectively.

The present article provides a guide for the conduction and analysis of three conditioning-based protocols to evaluate impulsivity in rats. Impulsivity is ...

Design and Use of an Apparatus for Presenting Graspable Objects in 3D Workspace

Reaching and grasping are highly-coupled movements, and their underlying neural dynamics have been widely studied in the last decade. To distinguish reaching and grasping encodings, it is essential to present different object identities independent of their positions. Presented here is the design of an automatic apparatus that is assembled with a turning table and three-dimensional (3D) translational device to achieve this goal. The turning table switches different objects corresponding to different grip types while the 3D translational device transports the turning table in 3D space. Both are driven independently by motors so that the target position and object are combined arbitrarily. Meanwhile, wrist trajectory and grip types are recorded via the motion capture system and touch sensors, respectively. Furthermore, representative results that demonstrate successfully trained monkey using this system are described. It is expected that this apparatus will facilitate researchers to study kinematics, neural principles, and brain-machine interfaces related to upper limb function.

Presented here is a protocol to build an automatic apparatus that guides a monkey to perform the flexible reach-to-grasp task. The apparatus combines a 3D translational device and turning table to present multiple objects in an arbitrary position in 3D space.

Reaching and grasping are highly-coupled movements, and their underlying neural dynamics have been widely studied in the last decade. To distinguish ...

Safe Experimentation in Optical Levitation of Charged Droplets Using Remote Labs

The work presents an experiment that allows the study of many fundamental physical processes, such as photon pressure, diffraction of light or the motion of charged particles in electrical fields. In this experiment, a focused laser beam pointing upwards levitate liquid droplets. The droplets are levitated by the photon pressure of the focused laser beam which balances the gravitational force. The diffraction pattern created when illuminated with laser light can help measure the size of a trapped droplet. The charge of the trapped droplet can be determined by studying its motion when a vertically directed electrical field is applied. There are several reasons motivating this experiment to be remotely controlled. The investments required for the setup exceeds the amount normally available in undergraduate teaching laboratories. The experiment requires a laser of Class 4, which is harmful to both skin and eyes and the experiment uses voltages that are harmful.

Optical levitation is a method for levitating micrometer-sized dielectric objects using laser light. Utilizing computers and automation systems, an experiment on optical levitation can be controlled remotely. Here, we present a remotely controlled optical levitation system that is used both for educational and research purposes.

The work presents an experiment that allows the study of many fundamental physical processes, such as photon pressure, diffraction of light or the motion ...

Engineering

A Within-Subject Experimental Design using an Object Location Task in Rats

Object place recognition is a prominent method used to investigate spatial memory in rodents. This object place recognition memory forms the basis of the object location task. This paper provides an extensive protocol to guide the establishment of an object location task with the option of up to four repetitions using the same cohort of rats. Both weak and strong encoding protocols can be used to study short- and long-term spatial memories of varying strength and to enable the implementation of relevant memory-inhibiting or -enhancing manipulations. In addition, repetition of the test with the counterbalancing presented here allows the combination of results from two or more tests for within-subject comparison to reduce variability between rats. This method helps to increase statistical power and is strongly recommended, particularly when running experiments that produce high variation in individual behavior. This directly refines the study by increasing the data obtained from each animal and reducing the overall number of animals needed.&#160;Finally, implementation of the repeated object location task increases the efficiency of studies that involve surgical procedures by saving time and labor.

This protocol provides detailed steps for an object location task with four repetitions using the same cohort of rats. Weak and strong encoding can produce short- and long-term memories. The flexibility of the protocol with repetition can be beneficial for studies involving surgical operations by saving time and labor.

Object place recognition is a prominent method used to investigate spatial memory in rodents. This object place recognition memory forms the basis of the ...

Interactive and Visualized Online Experimentation System for Engineering Education and Research

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also research. Interactive and visualizing features, including theory-guided algorithm implementation, web-based algorithm design, customizable monitoring interface, and three-dimensional (3-D) virtual test rigs are discussed. To illustrate the features and functionalities of the proposed laboratories, three examples, including the first-order system exploration using a circuit-based system with electrical elements, web-based control algorithm design for virtual and remote experimentation, are provided. Using user-designed control algorithms, not only can simulations be conducted, but real-time experiments can also be conducted once the designed control algorithms have been compiled into executable control algorithms. The proposed online laboratory also provides a customizable monitoring interface, with which users can customize their user interface using provided widgets such as the textbox, chart, 3-D, and camera widget. Teachers can use the system for online demonstration in the classroom, students for after-class experimentation, and researchers to verify control strategies.

This work describes an online experimentation system that provides visualized experiments, including the visualization of theories, concepts, and formulas, visualizing the experimental process with three-dimensional (3-D) virtual test rigs, and visualizing the control and monitoring system using widgets such as charts and cameras.

Experimentation is crucial in engineering education. This work explores visualized experiments in online laboratories for teaching and learning and also ...

WebVR-Based Virtual Reality Laboratory System for Immersive Online Experiments

Online Virtual Reality Networked Control Laboratory Applied in Control Engineering Education

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the simulated laboratory environment through a virtual reality (VR) device and interacts with the experimental equipment, similar to hands-on experiments in a physical laboratory. In addition, the proposed system allows users to design their own control algorithms and observe the effects of different control parameters to enhance their understanding of the experiment. To illustrate the features of the proposed virtual laboratory, an example is provided in this paper, which is an experiment on a double inverted pendulum system. The experimental results show that the proposed system allows users to conduct experiments in an immersive and interactive manner and provides users with a complete experimental process from principal design to experimental operation. A solution is also provided to change any virtual laboratory into a WebVR-based virtual laboratory for education and training.

Author Spotlight: Enhancing Engineering Education via WebVR-Based Online Laboratories

This study describes a WebVR-based online virtual reality (VR) laboratory system that provides users with immersive and interactive experimentation capabilities supported by VR devices. The proposed system not only helps to enhance the realism of user participation in online experiments but is also applicable to a wide range of online laboratory frameworks.

Online laboratories play an important role in engineering education. This work discusses a WebVR-based virtual laboratory system. The user enters the ...

A Setup for Human Vision, Cognition, and Interaction in Real-Life Scenarios

A Naturalistic Setup for Presenting Real People and Live Actions in Experimental Psychology and Cognitive Neuroscience Studies

Perception of others&#39; actions is crucial for survival, interaction, and communication. Despite decades of cognitive neuroscience research dedicated to understanding the perception of actions, we are still far away from developing a neurally inspired computer vision system that approaches human action perception. A major challenge is that actions in the real world consist of temporally unfolding events in space that happen &#34;here and now&#34; and are actable. In contrast, visual perception and cognitive neuroscience research to date have largely studied action perception through 2D displays (e.g., images or videos) that lack the presence of actors in space and time, hence these displays are limited in affording actability. Despite the growing body of knowledge in the field, these challenges must be overcome for a better understanding of the fundamental mechanisms of the perception of others&#39; actions in the real world. The aim of this study is to introduce a novel setup to conduct naturalistic laboratory experiments with live actors in scenarios that approximate real-world settings. The core element of the setup used in this study is a transparent organic light-emitting diode (OLED) screen through which participants can watch the live actions of a physically present actor while the timing of their presentation is precisely controlled. In this work, this setup was tested in a behavioral experiment. We believe that the setup will help researchers reveal fundamental and previously inaccessible cognitive and neural mechanisms of action perception and will be a foundation for future studies investigating social perception and cognition in naturalistic settings.

Author Spotlight: A Novel Setup to Conduct Naturalistic Laboratory Experiments with Real Human Actors in Scenarios 

This study presents a naturalistic experimental setup that allows researchers to present real-time action stimuli, obtain response time and mouse tracking data while participants respond after each stimulus display, and change actors between experimental conditions with a unique system including a special transparent organic light-emitting diode (OLED) screen and light manipulation.

Perception of others&#39; actions is crucial for survival, interaction, and communication. Despite decades of cognitive neuroscience research dedicated to ...

Common Lab Glassware and Uses

Source: Laboratory of Dr. Neal Abrams &#8212; SUNY College of Environmental Science and Forestry
Glassware is a regular appearance in the professional chemistry laboratory, because it has a relatively low cost, extreme durability, and specific levels of precision. While some labware is being supplemented with plastic or even everyday kitchen materials, glass is still the standard material by which laboratory work is done. While there are few rules about glassware, there are some best practices for use that set the groundwork for good techniques in the lab.
Glass is ubiquitous in the chemistry laboratory, but not all glass is the same. Standard consumer-grade glass is known as &#34;soda-lime&#34; or &#34;float&#34; glass. It is good for many applications, but cracks under rapid heating and cooling applications due to expansion/contraction. Borosilicate glass is used to solve this problem in the lab. Made with an introduction of small amounts of boron, borosilicate glass has a very low coefficient of expansion, which prevents internal stresses. The most common trade name for borosilicate glass is Pyrex, the same type of glass used in some kitchen bakeware.
While borosilicate glass is thermally robust, the impurities found in borosilicate and standard glass lead to a limited temperature range and optical quality. Fused silica, or quartz, is used in situations where glass needs to be heated above 450 &#176;C or to be transparent to UV light. Fused silica is chemically-pure silicon dioxide with no impurities and a very high melting point above 1,600 &#176;C. The easiest way to tell the difference between borosilicate glass and fused silica in the lab is to look down the long axis of a piece of glassware. A greenish color is indicative of borosilicate impurities, whereas fused silica is optically clear and colorless.

Lab Glassware: Qualitative, Quantitative and Procedural Uses

Source: Laboratory of Dr. Neal Abrams &#8212; SUNY College of Environmental Science and Forestry
Glassware is a regular appearance in the professional ...