Biology subjects

Goodale, M. A.

Publications and source records attributed to Goodale, M. A..

5 recordsLinked to original sources

bioRxiv2025

Separating error from bias: A new framework for facial age estimation in humans and AIs

Apparent facial age plays an important role in social interactions, serving a meaningful marker of biological aging. Although both humans and AIs achieve reasonable accuracy in estimating age from a persons face, performance remains imprecise, leaving substantial room for errors and biases. Drawing on principles from classical psychophysics, we demonstrate that the existing literature on age estimation suffers from a critical theoretical and methodological shortcoming, which casts doubt on established findings. We show that the conventional measure used to benchmark the accuracy of human and AI performance is fundamentally confounded by response bias. Consequently, we introduce a novel measure that eliminates this confound. A revised framework based on simulated data, reanalysis of existing data, and new experimental results, reveals fresh insights into how facial age is processed by humans and AIs. Our structure opens up new directions for future research and applications in the study of aging.

neuroscience↗

bioRxiv2025

Are online corrections really a distinct class of movement?

Humans have a remarkable capacity to adjust reaching movements rapidly and accurately when visual targets jump to a new location. The short latency of such online corrections has led to the hypothesis that they constitute a distinct class of movement and arise from an automatic pilot that is selectively engaged only during ongoing movements. Here, we test this idea by measuring muscle recruitment, force, and kinematics in a jumping target reaching task. In separate blocks of trials, participants were instructed to respond to target jumps by (1) following the jumped target, (2) stopping the on-going movement, or (3) ignoring the jumped target. This allowed us to establish the automaticity and timing of responses to target jumps and to compare such measures to the original reaching movement initiated from rest. We find that the earliest phase of muscle recruitment elicited by the jumped target corresponds to a subcortical reflex, beginning at [~]80ms and ending by [~]120ms, preceding the onset of voluntary recruitment at [~]130ms. This reflex inexorably drives a reaching adjustment towards the new target in all three blocks; it is only somewhat reduced in the stop and ignore blocks. Critically, this earliest phase of muscle recruitment was also present at the exact same latency (80ms) for the original reaching movement initiated from rest. Thus, rather than supporting the model of online corrections as distinct class of movement that is mediated by an automatic pilot, our results suggest that all reaches, whether adjusted in mid-flight or initiated from rest, arise from a common nested control system featuring subcortical and cortical components whose influence can be strategically preset by task demands. Our results also reinforce the importance of considering movement biomechanics when interpreting kinematic latency differences across movements made in different situations.

neuroscience↗

bioRxiv2023

Rapid integration of face detection and task set in visually guided reaching

The superior colliculus (SC) has been increasingly implicated in the rapid processing of evolutionarily relevant visual stimuli like faces, but the behavioural relevance of such processing is not clear. The SC has also been implicated in the generation of upper-limb Express Visuomotor Responses (EVRs) on upper limb muscles, which are very short-latency (within [~]80 ms) bursts of muscle activity time-locked to visual target presentation. This reasoning led us to investigate the influence of faces on EVRs. We recorded upper limb muscle activity from young healthy participants as they reached toward left or right targets in the presence of a distractor stimulus presented on the opposite side. Across blocks of trials, we varied the instruction as to which stimulus served as the target or distractor. Doing so allowed us to assess the impact of instruction on muscle recruitment by examining trials when the exact same stimuli required a reach to either the left or right. We found that EVRs were uniquely modulated in tasks involving face selection, promoting reaches toward or away from faces depending on instruction. Follow-up experiments confirmed that this phenomenon required highly salient repeated faces, and was not observed to non-facial salient stimuli nor to faces expressing different affect. We conclude that our results attest to an integration of top-down task set and bottom-up feature detection to promote rapid motor responses to faces at latencies that match or precede the arrival of face information in human cortex. STATEMENT OF SIGNIFICANCEThe tecto-reticulo-spinal pathway is hypothesized to mediate the express visuomotor response (EVR). This study extends this hypothesis by demonstrating that face detection in the subcortex impacts low-latency movement via the EVR at latencies preceding cortical activity for face perception. To date, this constitutes the most direct evidence for direct behavioural relevance of rapid face detection in the brainstem. Further, we find that this response can be modulated by task context, allowing for different instruction-based responses given the exact same visual stimulus and implicating top-down cortical control of the EVR.

neuroscience↗

bioRxiv2020

The role of animal faces in the animate-inanimate distinction in the ventral temporal cortex

Animate and inanimate objects elicit distinct response patterns in the human ventral temporal cortex (VTC), but the exact features driving this distinction are still poorly understood. One prominent feature that distinguishes typical animals from inanimate objects and that could potentially explain the animate-inanimate distinction in the VTC is the presence of a face. In the current fMRI study, we investigated this possibility by creating a stimulus set that included animals with faces, faceless animals, and inanimate objects, carefully matched in order to minimize other visual differences. We used both searchlight-based and ROI-based representational similarity analysis (RSA) to test whether the presence of a face explains the animate-inanimate distinction in the VTC. The searchlight analysis revealed that when animals with faces were removed from the analysis, the animate-inanimate distinction almost disappeared. The ROI-based RSA revealed a similar pattern of results, but also showed that, even in the absence of faces, information about agency (a combination of animals ability to move and think) is present in parts of the VTC that are sensitive to animacy. Together, these analyses showed that animals with faces do elicit a stronger animate/inanimate response in the VTC, but that this effect is driven not by faces per se, or the visual features of faces, but by other factors that correlate with face presence, such as the capacity for self-movement and thought. In short, the VTC appears to treat the face as a proxy for agency, a ubiquitous feature of familiar animals. Significance StatementMany studies have shown that images of animals are processed differently from inanimate objects in the human brain, particularly in the ventral temporal cortex (VTC). However, what features drive this distinction remains unclear. One important feature that distinguishes many animals from inanimate objects is a face. Here, we used fMRI to test whether the animate/inanimate distinction is driven by the presence of faces. We found that the presence of faces did indeed boost activity related to animacy in the VTC. A more detailed analysis, however, revealed that it was the association between faces and other attributes such as the capacity for self-movement and thinking, not the faces per se, that was driving the activity we observed.

neuroscience↗

bioRxiv2018

Temporal evolution from retinal image size to perceived size in human visual cortex

Our visual system affords a distance-invariant percept of object size by integrating retinal image size with viewing distance (size constancy). Single-unit studies with animals have shown that real changes in distance can modulate the firing rate of neurons in primary visual cortex and even subcortical structures, which raises an intriguing possibility that the required integration for size constancy may occur in the initial visual processing in V1 or even earlier. In humans, however, EEG and brain imaging studies have typically manipulated the apparent (not real) distance of stimuli using pictorial illusions, in which the cues to distance are sparse and not congruent. Here, we physically moved the monitor to different distances from the observer, a more ecologically valid paradigm that emulates what happens in everyday life. Using this paradigm in combination with electroencephalography (EEG), we were able for the first time to examine how the computation of size constancy unfolds in real time under real-world viewing conditions. We showed that even when all distance cues were available and congruent, size constancy took about 150 ms to emerge in the activity of visual cortex. The 150-ms interval exceeds the time required for the visual signals to reach V1, but is consistent with the time typically associated with later processing within V1 or recurrent processing from higher-level visual areas. Therefore, this finding provides unequivocal evidence that size constancy does not occur during the initial signal processing in V1 or earlier, but requires subsequent processing, just like any other feature binding mechanisms.

neuroscience↗