Humans are altricial animals, meaning they are dependent on their caregivers to survive for a variety of life challenges, including obtaining food, keeping from harm’s way, and maintaining a stable core body temperature. In the social psychological literature, over 70 academic articles emerged testing effects pertaining to the latter (IJzerman, Hadi et al., 2022). For one specific example, IJzerman and colleagues (2012) predicted and found that being socially excluded (versus included) from an online ball-tossing game (“Cyberball”) leads to a significant decrease in peripheral skin temperature measured at the index finger of a non-dominant hand. However, the study suffered from multiple shortcomings. Although it was reasonably powered, current norms in psychological research require higher-powered testing. In addition, IJzerman and colleagues (2012) included no relevant moderators that could help better understand the relationship between exclusion and temperature, and the study was conducted in a single, cold, higher-income country. Finally, they measured peripheral temperature in a single body part that is known to be most sensitive to change. We, therefore, propose a new study that focuses on replicating the effect first and extending their Study 1 in several important ways. **Social thermoregulation in humans and other animals** Across the animal kingdom, temperature regulation is more costly metabolically when done alone than together (for a review of metabolic savings from huddling in several homeothermic endotherms, see Gilbert et al., 2010). Conserving and regulating body temperature is a basic metabolic process in mammals and it is fundamental for normal development. It is essential for survival in maintaining optimal body functionality and in maintaining optimal body functionality (Rocha IJzerman, 2021). In homeothermic endotherms (warm-blooded animals capable of regulating body temperature by generating heat internally), thermoregulation is a regulation of body temperature through a homeostatic mechanism controlling heat production in relation to heat loss, with the main aim of maintaining relatively constant temperature independently of environmental changes (McNab, 2002). Mammals typically rely on two broad types of thermoregulation: internal and external (behavioral) thermoregulation (Mota-Rojas et al., 2021). Behavioral thermoregulation can occur in a variety of ways: jumping in a pool, laying in the sun, or sharing heat with conspecifics; the latter is typically known as social thermoregulation. Social thermoregulation is a behavior of certain species to upregulate their core body temperature when the ambient temperature drops by sharing body heat. Social thermoregulation is often more efficient than internal forms of temperature regulation or other forms of behavioral thermoregulation (Gilbert et al., 2010). Social thermoregulation enables the reduction of body heat loss, cold stress exposure, and homeostatic energy costs, and consequently allows greater investment in growth, reproduction, and survival (Campbell et al., 2018; Morrison, 2016). Social thermoregulation is, however, not restricted to animals other than humans. Humans, like other homeothermic endotherms, have a need to keep their internal temperature stable as the ambient temperature fluctuates (IJzerman & Hogerzeil, 2017; Szabelska et al., 2021). Humans of course differ in many ways from other animals in regulating their temperature, as we possess a variety of mechanisms to regulate our temperature that do not directly involve other people. But these methods (clothes, houses, heaters) have been available for such a short time from an evolutionary perspective that the system responsible for these effects has unlikely to have disappeared. Even in the 18th and 19th century, reports exist that humans slept with many people in one bed in order to keep warm (Rocha IJzerman, 2021). Some evidence exists that social thermoregulation continues to play a role in adult human relationships. One preregistered experimental study showed that people are more likely to think of loved ones when in a cold (vs. warm) condition (e.g., IJzerman, Neyroud, et al., 2018), whereas self-reported desires to socially thermoregulate has repeatedly been found to be linked to feelings of loneliness (Wittmann et al., 2022). Of current interest is IJzerman et al’s 2012 study, which showed that social exclusion (versus inclusion) in an online ball-tossing game led to a decrease in peripheral temperature on the finger. Participants in this study first read an excerpt unrelated to the study to establish a baseline, were then alternatingly assigned to a control (inclusion) or experimental (exclusion) condition, while their peripheral temperature was measured on the index finger of their non-dominant hand through a device commonly used for industrial coolers, for a total of 24 times (with intervals of on average 15.6 s, measured with 0.03125° C). At the end of the experiment, the two groups differed on average 0.711° C in peripheral temperature. However, according to current standards, the study has several shortcomings. First, it was not pre-registered. Second, the study only had 67.20% power to detect an effect, if an effect existed. Third, the study was conducted in one cold, higher-income country, thus, with very little potential to generalize to other populations, particularly those from warmer climates. We therefore decided to replicate and extend the effect. **Extensions of the original study** Since the study has been conducted, several ideas emerged in the social thermoregulation literature that bear relevance to this specific effect, which can be split up into two broad categories: social and individual variables that could impinge on the social exclusion-peripheral temperature link and climatic variables that could alter the relationship between social exclusion and peripheral temperature. Additionally, we feel it is necessary to study a third category of effects, which pertains to the charting temperature changes across a few body parts - not just the finger - in terms of how people respond to social exclusion. On an individual and social level, IJzerman, Lindenberg et al. (2018) and IJzerman, Hadi et al. (2022) identified a number of variables that may moderate or be related to temperature manipulations, measurements of core body temperature, and/or measurements of peripheral temperature. These include measures of one’s social network, height, weight (IJzerman, Lindenberg et al, 2018), one’s attachment in close relationships (IJzerman, Neyroud et al., 2018), and one’s desire to regulate temperature individually or socially (Vergara et al., 2018). From an environmental perspective, the original study offered no possibility to generalize to other populations, as it was conducted in a student sample in the Netherlands (which has average summer temperatures between 20°C and 25°C and average winter temperatures between 0°C (32°F) and 4.4°C (39.9°F)). Yet, the literature so far offers little clarity on whether climate moderates the link of social thermoregulation effects. While IJzerman, Lindenberg et al. (2018) found the climate to matter for participation in diverse social networks, IJzerman, Hadi et al. (2022) did not find any moderating effects of climate for the social thermoregulation literature. It is thus necessary to start clearing up the effects of climate on social thermoregulation. Further, it is unclear which effects (if any) social exclusion has on body parts other than the index finger. Finger temperature is a reflection of peripheral temperature and often responds in the opposite direction to core body temperature, as the periphery protects the core from changing rapidly (Rocha IJzerman, 2021). The fingers are among the more sensitive body parts in temperature change; in a whole- and partial-body experiment, finger temperature has been found to vary by as much as 3 °C and changes in body temperature can vary by body part (Huizenga et al., 2004), with correlations between finger and wrist to be as low as r = .32 when temperature is manipulated through cold and warm water baths (Sarda et al., 2021). Further, a recent study investigating the validity of temperature measurement on different body parts revealed that wrist measurements are more stable than, for example, forehead measurements under a variety of circumstances (Ge et al., 2020). While there is a reasonable expectation of variance between body parts, there are also reasons to believe specific areas of the body are more important for thermoregulation. Brown adipose tissue, which is a type of fat that has been found to be crucial for individual (nonshivering) temperature regulation (Cannon & Nedergaard, 2004). Adult humans have several depots of brown adipose tissue, but several studies found that supraclavicular skin temperature can be used as a reliable marker of brown adipose tissue volume and activity (for an overview see Jimenez-Pavon et al., 2019). To further chart people’s thermoregulatory responses to social situations we extended the original measure (on the index finger of the non-dominant hand) to another finger (the pinky finger), to one on the wrist of non-dominant hand, and one on the supraclavicular area. **Research overview** The aim of the current study was thus to conduct a replication and extension of IJzerman et al.’s (2012) Study 1 on social exclusion and peripheral temperature. We will replicate the study with greater power and collect data in multiple countries other than the original to explore climatic differences. To explore individual and social differences and in line with IJzerman, Hadi et al.’s (2022) and Sarda et al.’s (2020) recommendations, we integrated their social thermoregulation protocol into our study to assess relevant climatic and social variables. Our study will allow us first to examine the replicability of the main effect showing that being socially excluded (versus included) leads to a decrease in peripheral body temperature and, second, to identify important moderators. **Reporting.** We report how we determined our sample size, all data exclusions, all manipulations, and all measures in the study. **Ethical approval.** Data were collected in accordance with the Declaration of Helsinki. This research was approved under an “umbrella” ethics proposal at the University of Belgrade, Serbia. Overarching IRB approval was obtained from the IRB of the Department of Psychology, University of Belgrade, Serbia. In addition, all laboratories obtained local IRB approval before the last round of Stage 1 manuscript submission. The IRB approvals are available on our OSF project page: https://osf.io/v5s6d/.