Staircase Procedure Research Articles

Method for the design and evaluation of binary sensitivity tests

Abstract For many materials or specimen, their resistance to stress is an important (safety) characteristic. The target value is the event stress, i.e., the value of the stress at which the (adverse) event occurs. Depending on the test procedure and the test items, the event stress cannot always be measured directly but must be determined by binary sensitivity tests. A method for the evaluation of binary sensitivity tests based on the principle of Maximum Likelihood is presented and compared to other methods (traditionally) applied. Sensitivity testing of explosives and fatigue testing of metallic materials are used as real examples to illustrate application of the method and to compare actual results. The method presented delivers not only the estimate of the stress at any specified probability of the event but also the respective 95 % confidence interval. Application of the method is facilitated because it does not require the data to be obtained in a staircase procedure, can process any kind of input data (e.g., as measured or logarithmic), and does not require the stress levels to be equidistant. The method is easily applicable for any laboratory because it is implemented into an Excel file, which is made freely available at https://www.statistics-wilrich.info.

An open-access database of video stimuli for action observation research in neuroimaging settings: psychometric evaluation and motion characterization.

Video presentation has become ubiquitous in paradigms investigating the neural and behavioral responses to observed actions. In spite of the great interest in uncovering the processing of observed bodily movements and actions in neuroscience and cognitive science, at present, no standardized set of video stimuli for action observation research in neuroimaging settings exists. To facilitate future action observation research, we developed an open-access database of 135 high-definition videos of a male actor performing object-oriented actions. Actions from 3 categories: kinematically natural and goal-intact (Normal), kinematically unnatural and goal-intact (How), or kinematically natural and goal-violating (What), directed toward 15 different objects were filmed from 3 angles. Psychometric evaluation of the database revealed high video recognition accuracy (Mean accuracy = 88.61 %) and substantial inter-rater agreement (Fleiss' Kappa = 0.702), establishing excellent validity and reliability. Videos' exact timing of motion onset was identified using a custom motion detection frame-differencing procedure. Based on its outcome, the videos were edited to assure that motion begins at the second frame of each video. The videos' timing of category recognition was also identified using a novel behavioral up-down staircase procedure. The identified timings can be incorporated in future experimental designs to counteract jittered stimulus onsets, thus vastly improving the sensitivity of neuroimaging experiments. All videos, their psychometric evaluations, and the timing of their frame of category recognition, as well as our custom programs for performing these evaluations on our, or on other similar video databases, are available at the Open Science Framework (https://osf.io/zexc4/).

Design and Perception of a Soft Shape Change Beneath a Smartwatch

We explore the design of a watch that can deliver notifications through shape changes, with a specific focus on changes in curvature at the back of the watch face. We explain our design choices and the challenges we faced while creating such a watch. We conducted an experimental study to determine the absolute detection threshold (ADT) of this novel form of feedback. We compared the ADT of two different watches, both of which have a back face that can change its curvature and make contact with the wearer's wrist to notify them. These two watches exhibit different shapes when inflated with high air pressure. To determine the ADT, we conducted a standard two-down, one-up adaptive staircase procedure. Our findings show that an ADT of 3.86 psi is required to inflate the back surface for detection by participants. Overall, our qualitative findings indicate that participants enjoyed this novel type of feedback and could feel different sensations with each watch.

The duration discrimination respiratory task: A new test to measure respiratory interoceptive accuracy.

Interoception, which refers to the perception of body's internal state, is implicated in emotional processes and psychopathological disorders. Over the last decades, different tools have been developed to measure interoceptive accuracy, or the ability to accurately perceive physiological signals. Most of these tools have focused on cardiac interoception, but respiratory interoception has been less investigated due to the more complex and less portable equipment required. In this study, we suggest a new duration discrimination respiratory (DDR) task that does not require complex equipment. Using an adaptive staircase procedure, this task aims to determine an individual's ability to detect exhalation longer than their resting reference duration. One hundred and twenty-three healthy subjects completed the DDR task, an interoceptive task of heart rate discrimination, and filled out questionnaires on interoceptive awareness (Multidimensional Assessment of Interoceptive Awareness), alexithymia (Toronto Alexithymia Scale [TAS]), affects (Positive and Negative Affect Scale [PANAS]), and anamnestic. Results demonstrated a good internal consistency (Cronbach's alpha = .93) of the DDR task. On average, subjects needed 99.22% (SD = 36.38) of their reference exhalation time in addition to reference exhalation to detect a prolonged exhalation. Higher self-reported fitness levels, not counting during the DDR task and lower difficulty in describing feelings (TAS subscale), predicted higher respiratory discrimination duration. In conclusion, this study demonstrates the utility of the DDR task as a valid measure of interoception.

No evidence for top-down expertise effects on action perception in sprinters using static images

Athletes have been found to demonstrate a superior ability to detect subtle variations in dynamic displays (e.g., point-light displays and videos) depicting expert actions compared to non-athletes. The current study aimed to determine whether this advantage also exists when dynamic information is unavailable (i.e., using static images). Using a staircase procedure, two frames from a video depicting an athlete either walking (everyday action) or performing a sprint start (expert action) were presented, and athletes (sprinters) and non-athletes were asked to indicate whether the images were identical or different. We examined whether presenting the images sequentially (temporal task) or simultaneously (spatial task) influenced participants' discrimination performance. We predicted that the sprinters would outperform the non-sprinters in the spatial task as body postures could be compared directly but not in the temporal task due to larger representational momentum effects for athletes. Contrary to our hypotheses, the sprinters and non-sprinters performed similarly in all tasks and conditions. In line with the prediction that representational momentum may impair performance, participants’ thresholds were lower for the spatial than the temporal task. However, post-hoc analysis suggested that this effect is likely to be better explained by a task order effect whereby participants who completed the temporal task first exhibited an advantage in the spatial task, while there were no performance differences for participants who completed the opposite task order. In sum, our results provide no evidence for the idea that motor expertise affects action perception (i.e., perceptual resonance) in a simple psychophysical task employing static images.

Feature variability determines specificity and transfer in multiorientation feature detection learning.

Historically, in many perceptual learning experiments, only a single stimulus is practiced, and learning is often specific to the trained feature. Our prior work has demonstrated that multi-stimulus learning (e.g., training-plus-exposure procedure) has the potential to achieve generalization. Here, we investigated two important characteristics of multi-stimulus learning, namely, roving and feature variability, and their impacts on multi-stimulus learning and generalization. We adopted a feature detection task in which an oddly oriented target bar differed by 16° from the background bars. The stimulus onset asynchrony threshold between the target and the mask was measured with a staircase procedure. Observers were trained with four target orientation search stimuli, either with a 5° deviation (30°-35°-40°-45°) or with a 45° deviation (30°-75°-120°-165°), and the four reference stimuli were presented in a roving manner. The transfer of learning to the swapped target-background orientations was evaluated after training. We found that multi-stimulus training with a 5° deviation resulted in significant learning improvement, but learning failed to transfer to the swapped target-background orientations. In contrast, training with a 45° deviation slowed learning but produced a significant generalization to swapped orientations. Furthermore, a modified training-plus-exposure procedure, in which observers were trained with four orientation search stimuli with a 5° deviation and simultaneously passively exposed to orientations with high feature variability (45° deviation), led to significant orientation learning generalization. Learning transfer also occurred when the four orientation search stimuli with a 5° deviation were presented in separate blocks. These results help us to specify the condition under which multistimuli learning produces generalization, which holds potential for real-world applications of perceptual learning, such as vision rehabilitation and expert training.

The effect of target and background texture on relative depth discrimination in a virtual environment

The spatial frequency (SF) content of an object’s texture is an important cue for depth perception, although less is known about the role of background texture. Here, we used bandpass-filtered noise patterns to systematically study the interactions between target and background textures in a virtual environment. During the trials, three square targets were presented at 3 m against a background wall 6 m away from the observer. One of the squares was presented closer than the other two, and the subjects had to indicate it with a key press. The threshold distance from the two reference tiles was determined using a staircase procedure. Both the target and background were tested with different combinations of SF textures and a non-textured gray, which were rendered onto the flat surfaces. Against a gray background, the distance thresholds were smallest when the targets were presented with a mid-SF texture. Performance declined significantly with a non-textured target against a textured background. With different combinations of target-background texture, the background texture significantly affected the performance. We propose several hypotheses to explain the behavioral result. Understanding the effect of surrounding texture can be useful in improving the depth perception experience in virtual reality.

Visual field asymmetries in visual word form identification

Visual performance across the visual fields interacts with visual tasks and visual stimuli, and visual resolution decreases as a function of eccentricity, varying at isoeccentric locations. In this study, we investigated the extent of asymmetry and the rate of change in visual acuity threshold for visual word form (VWF) identification at horizontal and vertical azimuths across the fovea, and at eccentricities of 1°, 2°, 4°, 6° and 8° for 10%, 20%, 40%, and 80% contrast levels, to determine whether and how the eccentricities, meridians, and contrasts modulated the VWF identification acuity threshold. The stimuli were 16 traditional Chinese characters of similar legibility. Participants pressed a key to indicate the character presented, either monocularly or binocularly, at one of 21 randomly selected locations. A staircase procedure was used to determine the threshold, and a multiple linear regression model was used to fit the linear cortical magnification factor (CMF). We found that (1) the asymmetry was most pronounced on the vertical and superior azimuths, (2) the asymmetry between the right and left azimuths was not significant, (3) the CMF was significantly smaller on the vertical azimuth than on the horizontal azimuth, (4) the CMF was smaller on the superior vertical azimuth than on the inferior azimuth, and (5) monocular viewing and low contrast enhanced the CMF difference between azimuths. In conclusion, vertical and horizontal azimuths, location of eccentricity, contrast levels of word symbols, and monocular/binocular viewing have different effects on visual field asymmetry and cortical magnification factors.

Conscious perception of fear in faces: Insights from high-density EEG and perceptual awareness scale with threshold stimuli

Contrary to the extensive research on processing subliminal and/or unattended emotional facial expressions, only a minority of studies have investigated the neural correlates of consciousness (NCCs) of emotions conveyed by faces. In the present high-density electroencephalography (EEG) study, we first employed a staircase procedure to identify each participant's perceptual threshold of the emotion expressed by the face and then compared the EEG signals elicited in trials where the participants were aware with the activity elicited in trials where participants were unaware of the emotions expressed by these, otherwise identical, faces. Drawing on existing knowledge of the neural mechanisms of face processing and NCCs, we hypothesized that activity in frontal electrodes would be modulated in relation to participants' awareness of facial emotional content. More specifically, we hypothesized that the NCC of fear seen on someone else's face could be detected as a modulation of a later and more anterior (i.e., at frontal sites) event-related potential (ERP) than the face-sensitive N170. By adopting a data-driven approach and cluster-based statistics to the analysis of EEG signals, the results were clear-cut in showing that visual awareness of fear was associated with the modulation of a frontal ERP component in a 150–300 msec interval. These insights are dissected and contextualized in relation to prevailing theories of visual consciousness and their proposed NCC benchmarks.

Finding the ratio of perceived duration between tones with flat and percussive amplitude envelopes

The extensive literature on duration assessment generally uses tones with clear onsets and offsets. However, simplistic sounds can fail to evoke the same processes used when listening to sounds with time varying amplitude envelopes (Schutz & Gillard, 2020). To facilitate future research on the duration assessment of time varying tones, here we explore the ratio at which constant amplitude ‘flat’ and varying amplitude ‘percussive’ tones are perceived as the same duration. We will use an adaptive staircase procedure, in which flat and percussive tones are presented in pairs and participants state which tone sounded longer in duration. Each response changes the duration difference on subsequent trials and continues until responses converge around a specific point, with convergence defined as four consecutive reversals in response direction. One instance of these trials constitutes a single staircase; we will then calculate the millisecond point of subjective equality between flat and percussive tones by finding the average point of convergence between multiple, interleaved staircases. Beyond providing guidance on stimulus durations for studies comparing amplitude envelope, we aim to shed light on the process of duration assessment in sounds with time-varying amplitude envelopes.

Intention offloading: Domain-general versus task-specific confidence signals

Intention offloading refers to the use of external reminders to help remember delayed intentions (e.g., setting an alert to help you remember when you need to take your medication). Research has found that metacognitive processes influence offloading such that individual differences in confidence predict individual differences in offloading regardless of objective cognitive ability. The current study investigated the cross-domain organization of this relationship. Participants performed two perceptual discrimination tasks where objective accuracy was equalized using a staircase procedure. In a memory task, two measures of intention offloading were collected, (1) the overall likelihood of setting reminders, and (2) the bias in reminder-setting compared to the optimal strategy. It was found that perceptual confidence was associated with the first measure but not the second. It is shown that this is because individual differences in perceptual confidence capture meaningful differences in objective ability despite the staircase procedure. These findings indicate that intention offloading is influenced by both domain-general and task-specific metacognitive signals. They also show that even when task performance is equalized via staircasing, individual differences in confidence cannot be considered a pure measure of metacognitive bias.

Contrast threshold recovery after bleaching during cone‐mediated mesopic adaptation: The effect of test conditions

Aims/Purpose: To determine the optimal luminance conditions and the staircase procedures for evaluating the time course of macular contrast sensitivity recovery after photobleaching in order to decide the best protocol to assess cone‐mediated mesopic adaptation.Methods: The dynamics of contrast threshold (CT) recovery following photopigment bleach were measured psychophysically for five minutes in twenty‐four healthy adults (23.7 ± 3.7 years old). The stimuli used were sine‐wave gratings of low‐spatial frequency (1 cycle‐per‐degree). In each subject, six tests were performed, combining three luminance levels (0.1, 1.0, and 10 cd/m2) and two modified staircase procedures (3‐down/1‐up and 2‐down/1‐up) to estimate CTs. The test order was randomized, conducted in two visits, with a 15‐min washout period between tests. Outlier detection techniques were applied to verify the integrity of the sample. Non‐linear exponential‐based optimization was adopted to fit CT recovery functions to estimate the time constant (τ, seconds) of cone sensitivity recovery and the final CT (CTf, log units). Classical and heteroscedastic ANOVA analyses were performed to assess the effect of test conditions.Results: The 2‐down/1‐up staircase allowed for denser point sampling of CTs measurements than the 3‐down/1‐up. Under the lowest luminance test condition, the CT recovery was modelled by bumpier functions, for both staircases procedures, than the other luminance levels. Mean cone τ increased (21.7, 42.5, and 72.0 seconds (p < 0.001)) and CTf worsened (−1.99, −1.85, and − 1.47 log units (p < 0.001)) as luminance level decreased. The best fit (median R2 = 0.87) was achieved under 1 cd/m2 mesopic luminance conditions. There were no statistically significant differences in mean cone τ and CTf between the two staircases procedures.Conclusions: An intermediate mesopic light level and a 2‐down/1‐up staircase provided the best protocol for assessing cone‐mediated mesopic adaptation.

A colour vision test assisted by neural networks

Aims/Purpose: Traditional computerized colour vision tests resort to the magnitude of chromatic thresholds to determine the quality of the colour vision of an observer. The limits of perceived colours are tested against a background that will be conspicuous to normal colour vision observers, but inconspicuous to colour vision deficient (CVD) observers. The purpose of this work was to implement a Neural Network capable of performing independent and automatic classification of the colour vision of an observer, using as inputs the sRGB chromaticity coordinates, response times, and eye movements obtained using a colour vision test on a computer screen calibrated in colour and luminance (Display++).Methods: Chromatic discrimination limits were estimated using a staircase procedure that tested colour vision close to the dichromatic confusion lines. Only the last 8 responses were considered in the analysis. 50 normal colour vision observers and 8 CVD observers performed the test on Display++. CVD participants were diagnosed using the results of the anomaloscope and the CAD colour vision tests. A Sequential Neural Network was implemented with a dense structure (256–128–64‐16‐1 nodes), with relu and sigmoid activation functions, dropout commands to prevent overfitting, the Adam optimizer, and the binary crossentropy loss function. The performance of the neural network was estimated by computing its accuracy, where variables are related to the results obtained after training the Neural Network and inspecting the test results. The database was divided into a training/test following different splitting strategies: T1 observers' responses considering sRGB coordinates, response times, and eye movements. T2 observers' responses considering only sRGB coordinates.Results: The averages and standard deviations of the estimated accuracy for five consecutive trials with a random division between training/test for conditions T1 and T2 was 91% ± 7% and 93% ± 5% respectively. It was found that the implemented neural network had an accuracy of more than 90% across all conditions.Conclusions: The accuracies found across conditions considered seem to indicate that the implemented Neural Network can analyse and classify the colour vision of human observers, with an accuracy greater than 90% of success.

A colour Vision Test – Comparing results between computer screens

Aims/Purpose: A colour vision test was developed to run on web browser without specific hardware. It can estimate observers' colour vision thresholds, response times and eye movements with a webcam. The aim of this work was to compare the chromatic thresholds (CT) obtained for normal colour vision observers when estimated on calibrated and uncalibrated computer screens.Methods: Four squares with random luminance noise were presented on a uniform grey background. One square was randomly selected to present a colour with a particular hue and saturation. Twenty‐six hues were tested on or near the dichromatic confusion lines. CT for each hue were estimated after a staircase procedure, and by computing the colour difference between the observers' CT and the reference white of the screen in use. The observers' task was to point and select the coloured square with the computer mouse. Two conditions were considered: a condition where the uncalibrated screen of the participants' laptop was used (L), and a condition using a screen calibrated in colour and luminance (D). The setup for D condition was equal across observers ensuring the same stimulus size and colour, observers' distance to screen and dark environment. The setup for L condition was uncontrolled but observers were guided towards providing information about pixel size, using a dark environment, disabling screen night light mode, using a laptop screen, and ensuring that screen brightness and zoom were adequate.Results: 48 normal colour vision observers performed this test on D condition, while a subset of 45 observers repeated this test on L condition. CT were averaged across observers for both conditions. It was found that CT are comparable across different screens and correlatable with traditional colour vision tests. It was also found that hues at degrees 157°,162°,167°,179°,185° and 347° had statistical differences (p < 0.05) when comparing conditions L and D.Conclusions: These results seem to indicate that the assumptions made to run the colour vision test on unknown computer screens with the instructions given, may be sufficient to obtain CT comparable to traditional colour vision tests, even if the test was done in non‐controlled conditions.

Automated Speech Audiometry: Can It Work Using Open-Source Pre-Trained Kaldi-NL Automatic Speech Recognition?

A practical speech audiometry tool is the digits-in-noise (DIN) test for hearing screening of populations of varying ages and hearing status. The test is usually conducted by a human supervisor (e.g., clinician), who scores the responses spoken by the listener, or online, where software scores the responses entered by the listener. The test has 24-digit triplets presented in an adaptive staircase procedure, resulting in a speech reception threshold (SRT). We propose an alternative automated DIN test setup that can evaluate spoken responses whilst conducted without a human supervisor, using the open-source automatic speech recognition toolkit, Kaldi-NL. Thirty self-reported normal-hearing Dutch adults (19-64 years) completed one DIN + Kaldi-NL test. Their spoken responses were recorded and used for evaluating the transcript of decoded responses by Kaldi-NL. Study 1 evaluated the Kaldi-NL performance through its word error rate (WER), percentage of summed decoding errors regarding only digits found in the transcript compared to the total number of digits present in the spoken responses. Average WER across participants was 5.0% (range 0-48%, SD = 8.8%), with average decoding errors in three triplets per participant. Study 2 analyzed the effect that triplets with decoding errors from Kaldi-NL had on the DIN test output (SRT), using bootstrapping simulations. Previous research indicated 0.70 dB as the typical within-subject SRT variability for normal-hearing adults. Study 2 showed that up to four triplets with decoding errors produce SRT variations within this range, suggesting that our proposed setup could be feasible for clinical applications.

Auditory model-based parameter estimation and selection of the most informative experimental conditions

Identifying the causes underlying a person’s hearing impairment is challenging. It requires linking the results of listening tests to possible pathologies of the highly non-linear auditory system. This process is further aggravated by restrictions in measurement time, especially in clinical settings. A central but difficult goal is thus, to maximize the diagnostic information that is collectable within a given time frame. This study demonstrates the practical applicability of the model-based experiment-steering procedure introduced in Herrmann and Dietz (2021, Acta Acustica, 5:51). The approach chooses the stimuli that are presented and estimates the model parameters best predicting the subject’s performance using a maximum-likelihood method. The same binaural tone-in-noise detection task was conducted using two measurement procedures: A standard adaptive staircase procedure and the model-based selection procedure based on an existing model. The model-steered procedure reached the same accuracy of model parameter estimation in on average only 42% of the time that was required with the standard adaptive procedure. Difficulties regarding the choice of a reliable model and reasonable discretization steps of its parameters are discussed. Although the physiological causes of an individual’s results cannot directly be inferred using this procedure, a characterization in terms of functional parameters is possible.

Temporal Detection Threshold of Audio-Tactile Delays With Virtual Button.

Synchronization of audio-tactile stimuli represents a key feature of multisensory interactions. However, information on stimuli synchronization remains scarce, especially with virtual buttons. This work used a click sensation produced with traveling waves and auditory stimulus (a bip-like sound) related to a virtual click for a psychological experiment. Participants accomplish a click gesture and judge if the two stimuli were synchronous or asynchronous. Delay injection was performed on the audio (haptic first) or the click (audio first). In both sessions, one stimulus follows the other with a delay ranging from 0-700 ms. We use weighted and transformed 3-up/1-down staircase procedures to estimate people's sensitivity. We found a threshold of 179 ms and 451 ms for the auditory first and haptic first conditions, respectively. Statistical analysis revealed a significant effect between the two stimuli' order for threshold. Participants' acceptable asynchrony decreased when the delay was on the haptic rather than on the audio. This effect could be due to the natural experience in which the stimuli tend to be first tactile and then sonorous rather than the other way around. Our findings will help designers to create multimodal virtual buttons by managing audio-tactile temporal synchronization.

Gaze behaviour during multiple object tracking is dependent on binocular vision integrity.

Despite the critical importance of binocular vision integrity in daily activities, there exists limited understanding of how alterations in binocular vision integrity impact gaze behaviour during dynamic, complex psychomotor skills. This study aimed to measure how alterations in binocular vision integrity, created by Bangerter filters (BF), affect gaze behaviour during multiple object tracking (MOT). During the experiment, 22 volunteers completed the MOT task under three different visual conditions. The first condition involved natural binocular viewing, while the second and third conditions used 0.4 and 0.2 neutral density BF, respectively, resulting in monocular blur in the sensorially dominant eye. During the MOT task, participants were instructed to track three of eight balls for 10 s, and the speed was adjusted using a staircase procedure. Throughout the task, the following gaze parameters were recorded: fixation duration, saccade duration, amplitude and frequency as well as blink rate. During MOT execution, participants employed three gaze strategies regardless of viewing conditions: saccadic movements were predominant, followed by maintaining fixation on a central location throughout the trial and to a lesser extent, smooth pursuit eye movements. There was a significant effect of manipulating viewing conditions on the MOT scores (p = 0.046, η2 = 0.09). As the viewing conditions became more difficult, we observed a decrease in fixation duration (p = 0.004, η2 = 0.16) and blink rate (p < 0.001, η2 = 0.20) and an increase in saccadic amplitude (p < 0.001, η2 = 0.29). The results support the notion that perceptual-cognitive skills depend on the integrity of binocular vision, underscoring the sensitivity of gaze behaviours to any impairment of binocular function.

Gender Differences in Mental Rotational Training Based on Computer Adaptive Tests.

Mental rotation tasks have been widely used to assess individuals' spatial cognition and the ability to mentally manipulate objects. This study employed a computerized adaptive training method to investigate the behavioral performance of participants of different genders in mental rotation tasks with different rotation angles before and after training. A total of 44 Chinese university students participated in the experiment, with the experimental group undergoing a five-day mental rotation training program. During the training phase, a three-down/one-up staircase procedure was used to adjust the stimulus levels (response time) based on participants' responses. The results showed that the training had a facilitative effect on the mental rotation ability of both male and female participants, and it was able to eliminate the gender differences in mental rotation performance. Regarding the angles, we observed that the improvement in the angles involved in the training was significantly higher compared to untrained angles. However, no significant differences in improvement were found among the three trained angles. In summary, these findings demonstrate the effectiveness of computerized adaptive training methods in improving mental rotation ability and highlight the influence of gender and angles on learning outcomes.

A Novel Approach to Assessing Infant and Child Mental Rotation.

Mental rotation is a critically important, early developing spatial skill that is related to other spatial cognitive abilities. Understanding the early development of this skill, however, requires a developmentally appropriate assessment that can be used with infants, toddlers, and young children. We present here a new eye-tracking task that uses a staircase procedure to assess mental rotation in 12-, 24-, and 36-month-old children (N = 41). To ensure that all children understood the task, the session began with training and practice, in which the children learned to fixate which of two houses a giraffe, facing either left or right, would approach. The adaptive two-up, one-down staircase procedure assessed the children's ability to fixate the correct house when the giraffe was rotated in 30° (up) or 15° (down) increments. The procedure was successful, with most children showing evidence of mental rotation. In addition, the children were less likely to succeed as the angle of rotation increased, and the older children succeeded at higher angles of rotation than the younger children, replicating previous findings with other procedures. The present study contributes a new paradigm that can assess the development of mental rotation in young children and holds promise for yielding insights into individual differences in mental rotation.