Human vs Humanoid. A behavioral investigation of the individual tendency to adopt the intentional stance

Abstract

Humans interpret and predict behavior of others with reference to mental states or, in other words, by means of adopting the intentional stance. How to measure the likelihood to adopt the Intentional Stance towards humanoid robots still remain to be addressed. The present study investigated to what extent individuals adopt the intentional stance in explaining the behavior of two agents (a humanoid robot and a human). The present paradigm required participants to judge mentalistic or mechanistic descriptions as fitting or not to the displayed behaviors. We were able to measure their acceptance/rejection rate (as an explicit measure) and their response time (as an implicit measure). In addition, we examined the relationship between adopting the intentional stance and anthropomorphism. Our results show that at the explicit level (acceptance/rejection of the descriptions), participants are more likely to use mentalistic (compared to mechanistic) descriptions to explain other humans’ behavior. Conversely, when it comes to a humanoid robot, they are more likely to choose mechanistic descriptions. Interestingly, at the implicit level (response times), while for the human agent we found faster response time for the mentalistic descriptions, we found no difference in response times associated with the robotic agent. Furthermore, cluster analysis on the individual differences in anthropomorphism revealed that participants with a high tendency to anthropomorphize tend to accept faster the mentalistic description. In the light of these results, we argue that, at the implicit level, both stances are comparable in terms of “the best fit” to explain the behavior of a humanoid robot. Moreover, we argue that the decisional process on which stance is best to adopt towards a humanoid robot is influenced by individual differences of the observers, such as the tendency to anthropomorphize non-human agents.

Belief in sharing the same phenomenological experience increases the likelihood of adopting the intentional stance towards a humanoid robot

“…Thus, humans might anthropomorphize humanoid robots by ascribing typically human characteristics (Airenti, 2018;Epley et al, 2007Epley et al, , 2008Złotowski et al, 2014). Recently, several authors empirically investigated the adoption of the intentional stance towards robots (Marchesi et al, 2019;Marchesi, Spatola, et al, 2021;Thellman et al, 2017). For instance, Thellman and colleagues (Thellman et al, 2017) exposed participants to images of humans and humanoid robots.…”

“…This suggests that social cognition and the adoption of the intentional stance may be the default and spontaneous way of making sense of others (Abu-Akel et al, 2020;Meyer, 2019;Raichle, 2015;Schilbach et al, 2008;Spreng & Andrews-Hanna, 2015;. Moreover, recent studies reported that the spontaneous adoption of intentional stance towards robotic agents might be elicited by the individual tendency to anthropomorphize non-human agents (Marchesi, Spatola, et al, 2021;Spatola, Monceau, et al, 2020). Interestingly, the results of Marchesi et al's study (2019) showed also that individuals differed in their bias in adopting either one or the other stance towards a humanoid robot.…”

Is erring (only) human? A review of experimental evidence on how human likeness in failures affects sensorimotor signaling, intentionality attribution, and social inclusion of the iCub robot

“…we adopt the Design/Mechanical Stance. Recently, Marchesi and colleagues [21,22] developed a test to evaluate the likelihood of adopting Intentional Stance toward the iCub humanoid robot: the InStance Test (IST). It consists of 34 items in which users are presented with images of iCub engaged in different types of daily activities.…”

Effects of erring behavior in a human-robot joint musical task on adopting Intentional Stance toward the iCub robot

“…In the present study, the two types of erring behavior set a boundary between the user and the robot, since the mechanical error cannot be considered a feature of human agents, whereas a mismatch in sequence execution resembles a memory failure that often occurs in humans. We examined the adoption of Intentional Stance towards robots before and after a joint musical task, employing the Intentional Stance (InStance) Test developed and validated from our lab [8,12,14,15,18,19]. Also, before performing the task, we evaluated individual differences in attitudes towards robots to test whether they predicted the variation in the likelihood of adopting Intentional Stance before and after the musical joint task.…”

“…On the other hand, as manmade artifacts, the call for adopting the design stance. Indeed, a recent series of studies showed that humans can adopt either the intentional or the design/mechanical stance [11,12] to explain behaviors of the iCub robot [13] For example, Marchesi and colleagues [12,14] asked to users to judge between two different descriptions which one was better to explain the behaviors of the iCub robot or a human agent displayed in a visual scenario. The two possible explanations either referred to intentional or design stances.…”