Photographs of Actions: What Makes Them Special Cues to Social Perception

Forward effects from action observation: the role of attentional focus

After viewing an image representing an action on an object, we recognize the forward states of the seen action faster than the backward states. The present study exploits a variant of a new experimental paradigm to investigate cognitive mechanisms underlying this effect. Participants viewed a series of still photos of unfolding actions on objects, each followed by a photo depicting either one of three (instead of two of the original paradigm) different and temporally distant moments after the image or one moment before the image, along with photos of different actions. Experiment 1 revealed the classical forward effects in this new context: when the task was to judge whether the action in the second photo was the same as in the first photo, evaluations were faster for all forward photos than for backward photos. In Experiment 2, we examined the role of participants' attention to the object alongside the role of attention to action kinematics in triggering these "forward effects" by manipulating participants' attentional focus. As the results showed, evaluations were faster for all forward photos when the focus was on the action kinematics, but when the focus was on the object, evaluations were faster only for the last forward photo showing the final action state. These results seem to suggest that focusing on the object triggers a representation of the action goal and thus modulates the mental simulation underlying action anticipation.

Actions are characterized by 'canonical moments' in a sequence of movements

Understanding what others are doing is an essential aspect of social cognition that depends on our ability to quickly recognize and categorize their actions. To effectively study action recognition we need to understand how actions are bounded, where they start and where they end. Here we borrow a conceptual approach - the notion of 'canonicality' - introduced by Palmer and colleagues in their study of object recognition and apply it to the study of action recognition. Using a set of 50 video clips sourced from stock photography sites, we show that many everyday actions - transitive and intransitive, social and non-social, communicative - are characterized by 'canonical moments' in a sequence of movements that are agreed by participants to 'best represent' a named action, as indicated in a forced choice (Exp 1, n = 142) and a free choice (Exp 2, n = 125) paradigm. In Exp 3 (n = 102) we confirm that canonical moments from action sequences are more readily named as depicting specific actions and, mirroring research in object recognition, that such canonical moments are privileged in memory (Exp 4, n = 95). We suggest that 'canonical moments', being those that convey maximal information about human actions, are integral to the representation of human action.1.

Ultra-high field fMRI identifies an action-observation network in the common marmoset

The observation of others' actions activates a network of temporal, parietal and premotor/prefrontal areas in macaque monkeys and humans. This action-observation network (AON) has been shown to play important roles in social action monitoring, learning by imitation, and social cognition in both species. It is unclear whether a similar network exists in New-World primates, which separated from Old-Word primates ~35 million years ago. Here we used ultra-high field fMRI at 9.4 T in awake common marmosets (Callithrix jacchus) while they watched videos depicting goal-directed (grasping food) or non-goal-directed actions. The observation of goal-directed actions activates a temporo-parieto-frontal network, including areas 6 and 45 in premotor/prefrontal cortices, areas PGa-IPa, FST and TE in occipito-temporal region and areas V6A, MIP, LIP and PG in the occipito-parietal cortex. These results show overlap with the humans and macaques' AON, demonstrating the existence of an evolutionarily conserved network that likely predates the separation of Old and New-World primates.

ERP responses to sexual cues among young women attracted to men

Previous event-related potential (ERP) studies reported larger N170, P3, and late positive potential (LPP) amplitudes to sexual than nonsexual stimuli. These ERPs may not be specifically sensitive to processing sexual cues, however, because the sexual stimuli included information beyond sexual cues (e.g., faces, bodies, social interaction) to a greater extent than comparison stimuli. We investigated ERPs to stimuli that focused on sexual and nonsexual body regions, in different states of readiness for activity, to elucidate neural responses involved in processing sexual cues. Forty cisgender, primarily white, undergraduate women who were attracted to men (M_age  = 18.6, SD = 0.9) viewed images that varied by male body part (penis, arm) and activity state (rest, poised for activity). Participants viewed 40 images per category (flaccid penises, erect penises, outstretched arms, bent arms). Electroencephalography (EEG) was recorded using a 128-channel net, time-locked to the onset of each image. Using a whole-head cluster-mass approach, we found that the P3 was sensitive to sexual readiness-P3 amplitudes were larger to erect than flaccid penises, but not to bent than outstretched arms. The N170 and LPP components did not show evidence of similarly specific responses to sexual readiness, revealing potential dissociation of different neural processes commonly elicited in response to more complex sexual stimuli. An additional novel finding was that an anterior N270-400 was sensitive to sexual readiness. Findings clarify the brain's rapid responses to sexual stimuli, setting the stage for future research aimed at better understanding the neurocognitive processes that contribute to the coordination of sexual arousal.

Editorial: “Neuromodulation of Language, Cognition and Emotion”

Neuromodulation can be defined as the alteration of brain activity by delivering physical stimuli to a specific neural region [...]