Thirty feet is the distance that is automatically set around important public figures (Hall 1966, p.124).

This quote—taken from Hall’s seminal work on how people use space—suggests that people tend to keep further distance from powerful and high-status people. This behavior is generally interpreted as a sign of respect toward individuals in positions of power and authority, and as an indication that power affects self-representation in space. Powerful individuals are believed to “occupy more space” as if feeling powerful would magnify the spatial extension of the self in the area immediately surrounding the body—i.e., the peri-personal space. In the present research, we rely on the concept of peri-personal space (PPS) developed in neuroscience to empirically test the validity of this idea.

It is not just anecdotal evidence, but also a scientific fact, that people treat the area immediately surrounding the body—i.e., the peri-personal space—as if it were a spatial extension of the self (Blanke et al. 2015; Noel et al. 2015b; Serino 2019). A consistent body of neurophysiology and neuroimaging studies has indicated that PPS is a multisensory representation of the space near the body—encoded by a set of neurons in the fronto-parietal areas—where tactile information on one’s body is preferentially integrated with visual or auditory information from external stimuli as they approach the body (Graziano and Cooke 2006; Cléry et al. 2015; Di Pellegrino and Làdavas 2015). At a behavioral level, this is clearly shown by performance in cross-modal interaction tasks in which participants are asked to react as soon as possible to a tactile stimulation delivered on one’s own body while receiving an external concurrent (auditory or visual) stimulus. Although irrelevant to the task, a stimulus presented at closer distances (i.e., within the peri-personal space) facilitates the processing of the tactile input compared to the same stimuli presented farther in space (Macaluso and Maravita 2010; Canzoneri et al. 2012; Serino et al. 2015a). Importantly, the extent of space coded by the brain as PPS is not fixed. The size and shape of PPS representation vary as a function of interaction with external objects or other people. For instance, PPS representation extends when reaching an object (Brozzoli et al. 2010), when walking forward (Noel et al. 2015a), or after using a tool to reach the far space (Canzoneri et al. 2013). When facing another person, to simulate the space of social interaction, PPS representation adjusts to the type of relationship. When the partner of the relation is cooperative (Heed et al. 2010; Teneggi et al. 2013; Hobeika et al. 2019) or moral (vs. immoral) (Iachini et al. 2015a; Pellencin et al. 2018), PPS representation is more extended toward them. These findings suggest that PPS representation rapidly adjusts to the social context, too.

An intriguing and theoretically relevant question is at the core of the present research: whether PPS representation maps also onto some individual psychological dispositions and states. We investigated this question by examining PPS representation both in terms of its spatial extent (i.e., the PPS boundary) and its shape (i.e., differentiation between peri- and the extra-personal space resulting from the amount of multisensory processing allocated in the near vs. far space).

Concurrent available evidence supports this hypothesis. People, depending on individual differences, approach the world differently and this could also influence PPS representation, as this is ultimately a sensory–motor interface mediating individual–environment interaction (Serino 2019). Literature suggests that spatial representations largely varies across people, depending on different clinically relevant traits, such as schizotypal traits or anxiety (Sambo and Iannetti 2013; Iachini et al. 2015b; Di Cosmo et al. 2018; Ferroni et al. 2020). For instance, anxiety (measured by the State–Trait Anxiety Inventory, STAI; Spielberger et al. 1983) is linked to a larger individuals’ defensive PPS (Sambo and Iannetti 2013; Spaccasassi and Maravita 2020) or smaller reaching distance (Iachini et al. 2015b). The link between PPS extent and anxiety is in keeping with one of the key putative functions of PPS representation, namely, to anticipate potential contacts with threatening stimuli and to prepare defensive responses (Graziano and Cooke 2006). In the same perspective, Gherri and colleagues (Gherri et al. 2022) observed an inverse relationship between levels of empathy and the strength of multisensory integration within PPS, together with a reduced differentiation between peri- and extra-personal space. These results might indicate that individuals with higher levels of empathy tend to process self-related stimuli over a larger space in the presence of others.

Other findings in the same line of research suggest that psychological dispositions can also account for when and why PPS representation dynamically adjusts to the context. For instance, only when a threatening stimulus is present (e.g., dog, spider), PPS representation extends (Taffou and Viaud-Delmon 2014; Hobeika et al. 2019) and becomes more differentiated—in terms of multisensory processing—from the representation of the far space (de Haan et al. 2016). Importantly, these effects occur only in participants who are afraid of that specific threat. More recently, we have shown that the introduction of COVID-19-related social distancing measures resulted in a reduction of PPS extent and in a stronger near–far differentiation (Serino et al. 2021). Interestingly, individuals who were more afraid of being contaminated by pathogens (as evaluated with the Germ aversion subscale of the Perceived Vulnerability Scale (Duncan et al. 2009) and were more likely to take precautionary measures to avoid contacts had a stronger near–far differentiation.

As suggested above, research on individual psychological differences offers a unique perspective to investigate between-individuals variability in PPS representation, but also an opportunity to understand “when” and “why” PPS dynamically shapes to adapt to specific contexts. In the present research, we further investigated the role of individual psychological difference and examined in particular the influence of personal sense of power in PPS representation in both social (i.e., when facing another person) and non-social (i.e., in an empty corridor) context. In the further sections of the paper, we will first introduce the notion of the personal sense of power, relying mainly on research in social psychology, and then introduce possible hypotheses on how, when, and why feeling powerful would affect individuals’ PPS representation.

Power is a ubiquitous characteristic of the social and relational world. Power can be defined as the potential to influence others in psychologically meaningful ways (French et al. 1959; Guinote 2017). It is therefore a relational feature that is usually defined by the situation (e.g., working organization, family, etc.) and the roles people have in it (e.g., manager, subordinate, parent, child). Power can also be thought of as a psychological state, temporarily elicited by the context (e.g., the role), or stemming from the personality and therefore as a stable characteristic of the individual. In this regard, Anderson, John, and Kelter (Anderson et al. 2012) introduced the concept of a personal sense of power as the perception of one’s ability to influence others. Using a self-reported scale, they showed that some people simply feel more powerful than others, across situations. In the present research, we rely on this conceptualization to investigate the relationship between individual differences in the personal sense of power and the multisensory representation of PPS.

Whether it is elicited by roles or a stable self-perception, feeling powerful or powerless has a series of important downstream consequences on the individual’s affect, higher cognition, and motor behavior. For instance, powerful people have a more positive view of themselves (Wojciszke and Struzynska–Kujalowicz 2007) and a more optimistic perspective on events even if risky (Anderson and Galinsky 2006). Being powerless impairs executive functions (Smith et al. 2008), whereas being powerful increases the ability to ignore task-irrelevant information. Importantly for the present research, a high sense of power increases the tendency to take any action, whether this is in the service of personal desires or a pro-social act (Galinsky et al. 2003). For instance, participants primed with power are more likely to stop an annoying fan (Galinsky et al. 2003), but also more likely to run and help a victim in case of emergency (Baumeister et al. 1988) and to initiate an approach to motor response (Maner et al. 2010). Guinote (2017; Guinote and Chen 2018) has recently suggested a theoretical framework to integrate these findings into the literature. She suggests that power energizes the self and increases the goal-related approach motivation. Differently stated, powerful individuals are focused on their goal/s and act in a way that prioritizes the attainment of this goal. Thus, the effects of power on affect, cognition, and motor actions should be seen in relation to goal pursuit.

In the present research, we relied on the concept of power as a psychological disposition to investigate whether individuals feeling powerful and powerless differ in their multisensory representation of PPS. Despite its intuitiveness, this idea, to the best of our knowledge, has never been empirically investigated. Feeling powerful is a noteworthy psychological individual characteristic to examine in the context of PPS representation for at least three reasons.

First, it would provide a better understanding of the role of individual dispositions in PPS representation. Research up to now has mainly investigated traits with clinical relevance (e.g., anxiety, schizophrenia and phobia), while studies that examine the role of non-clinical individual characteristics are needed. Second, it contributes to the ongoing debate on the nature and functions of the PPS representation. Studies have shown that multisensory representation of PPS is immediately translated into potential motor responses (Cooke and Graziano 2004; Makin et al. 2009; Serino et al. 2009; Finisguerra et al. 2015), either to protect the body from threat or to support appetitive actions (Rizzolatti et al. 1997; Ladavas and Serino 2008; Cléry et al. 2015; de Vignemont and Iannetti 2015; Serino 2019). Given that power is linked to the tendency to act and more generally to an approach motivation, the present research would provide indications concerning the action-related function of PPS representation.

Finally, the present research would extend our knowledge about the role of top-down and social processes in PPS representation and ultimately its functions in social interactions. While the research on PPS plasticity in human–object interaction and in response to sensory–motor inputs has a long tradition, only more recently the field has investigated the mutual relationship between PPS representation and social interactions. In this context, up to now, research has focused on morality (Iachini et al. 2015a; Pellencin et al. 2018), cooperation (Heed et al. 2010; Hobeika et al. 2019; Dell’Anna et al. 2021), and fairness (Teneggi et al. 2013), but never, to the best of our knowledge, on power. This is surprising as power is an omnipresent feature of our social world and, most importantly, a dimension that people spontaneously use to structure social relations (Fiske et al. 1991).

In the present research we conducted two studies in which we relied on a visual–tactile interaction task to assess individuals’ PPS representation (Canzoneri et al. 2012; Teneggi et al. 2013; Pellencin et al. 2018) and on the scale of the personal sense of power (Anderson et al. 2012) to identify powerful and powerless participants. Based on a recent validation work (Paladino et al. 2022), this scale allowed to capture two facets or domains of the personal sense of power and to differentiate participants, accordingly, on the self-evaluation of one’s own ability to have (1) power over others’ opinion and (2) power over others’ behavior. Study 1 assessed the representation of multisensory PPS in the context of a potential social interaction by means of mixed reality (Serino et al. 2018). Participants were asked to respond as soon as possible to a tactile stimulation on their body, while a virtual object was approaching at six different distances between the participants and another person facing them. Despite being instructed to focus on the tactile stimulation and to ignore the visual stimuli, several studies in the literature (for a comprehensive review, see Serino 2019) demonstrated that reaction times to touch increase as a function of the perceived distance of the external object at the time of tactile inputs. The distance between the visual stimulus and the participants' bodies at which this multisensory effect occurs is used as a proxy for PPS representation. This enables measuring the spatial extent of PPS representation as well as the degree of differentiation between near and far space. These PPS indexes were studied in relationship between individual differences in personal sense of power as assessed by the scale of the personal sense of power (Anderson et al. 2012). Study 2 was designed to investigate whether the effect of personal sense of power on PPS representation depends on contextual demands that make this individual disposition cognitively relevant and accessible. In Study 2, we did not probe the PPS representation in a social context—as the presence of another person would inevitably make this relational feature relevant. Instead, we assessed it in a non-social context (i.e., an empty corridor) before and after a manipulation aimed at priming their perceived power (i.e., asking to remind an episode related to high vs. low sense of power). As in Study 1, participants’ personal sense of power over others’ behavior and others’ opinions was also measured. This experimental design allows to test the role of cognitive accessibility of personal sense of power and at the same time provides indications on whether power affects PPS tout court, that is, independent of contextual demands.