by Nanna M. Andersen | Published: 23.02.22 | Edited: 01.07.23
A review of the study: Rough-and-Tumble Play and the Development of the Social Brain By: Sergio M. Pellis and Vivien C. Pellis. Current Directions in Psychological Science 2007 16: 95. Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada In this study, we examine the importance of play fighting during early development and the effects of isolated rearing on social interactions. Play fighting, also known as rough-and-tumble play, involves rats wrestling and competing for access to the nape of their partner's neck. Contact with the nape results in nuzzling, while serious fighting involves biting the rump and lower flanks of the opposing rat's body (Pellis & Pellis, 1987). Adult rats that experience emotional and cognitive deficits often lack the opportunity to play with peers during their juvenile period. These rats exhibit social deficits such as hyper-defensiveness when approached by another rat, difficulties in reading social cues, and problems with social interactions (Pellis & Pellis, 2006). A Dutch study (Von Frijtag, Schot, van den Bos, & Spruijt, 2002) introduced a rat colony to an unfamiliar young adult male intruder. Some intruders were reared in isolation, while others had experienced play fighting with peers. The dominant male in the colony typically attacked the unfamiliar males. Intruder rats reared with peers quickly learned to avoid or experience diminished attacks by remaining crouched and motionless. In contrast, play-deprived intruder rats did not learn this important lesson and constantly provoked more serious attacks from the dominant male. Play-deprived rats also exhibited higher levels of stress hormones and experienced chronic stress (Von Frijtag et al., 2002). Overall, play-deprived rats displayed significant stress during social encounters and deficits in reading social cues and adopting strategies to alleviate social stress. This highlights the importance of providing young rats with the opportunity to engage in play fighting for their cognitive, emotional, and social development. It is crucial to consider that play-deprived rats lack all forms of social interactions due to their isolation (Pellis & Pellis, 2006). Additional studies by Dorothy Einon and her colleagues (Einon & Morgan, 1977) demonstrated that rats reared in conjoining cages with mesh netting separating them, allowing visual, olfactory, and tactile contact, still exhibited cognitive and social deficiencies as adults. Similarly, tests involving young rats reared with an adult but with limited play fighting also showed deficiencies in adulthood. However, isolated rats given access to an age-matched partner for one hour per day during the juvenile period performed as well as controls in cognitive tests as adults. Most of this hour was spent engaging in play fighting. Play fighting first occurs around the third week and peaks between 30 and 40 days of age, declining around the eighth to ninth week, during puberty (Pellis & Pellis, 2006). On a neurological level, highly social activities like play fighting activate certain parts of the brain. It is suggested that play fighting induces the release of growth factors in specific brain areas, promoting growth and development (Gordon, Burke, Akil, Watson, & Panksepp, 2003). Referencer
A review of the study: The Function of Play in Development of the Social Brain By: Pellis, Sergio & Pellis, Vivien & Broccard-Bell (Bell), Heather.University of California, San Diego The Function of Play in the Development of the Social Brain (2011). American Journal of Play. 2. 278-296. Building on the content of the previous study, we now delve into the subject of play fighting in adult rats. Although adult rats do engage in play fighting, the duration, frequency, and tactics of this behavior change with age. While rats remain consistent in their defensive reactions throughout their lives, the tactics they employ vary (Pellis, 2002b; Pellis and Pellis, 1987). Approximately 20 to 30 percent of the time, evasive tactics are utilized, but what undergoes change are the supine (laying on the back) and standing defense tactics. Additionally, the defensive reactions of rats are influenced by sex. Before the juvenile period, both sexes primarily employ the standing defense as their preferred tactic. However, as rats enter the juvenile phase, both sexes shift toward favoring the supine tactic. In males, as they reach puberty, they tend to prefer the standing defense, while females, as adults, continue to favor the supine defense (Pellis and Pellis, 1990; Smith et al., 1998). Males exhibit a higher tendency for play fighting compared to females, particularly during puberty when they strive to establish dominance relationships. Interestingly, dominant males consistently demonstrate the adult-typical pattern of play, utilizing the standing defense. On the other hand, subordinates or submissive rats exhibit variations in their defense patterns depending on the identity of their play partner (Pellis and Pellis, 1991b). When subordinate males engage in play with other subordinate males or females, they predominantly employ the standing defense. However, when playing with a dominant male, they primarily utilize the supine defense (Pellis and Pellis, 1992; Pellis et al., 1993; Smith et al., 1998). References
A review of the study: Adult-juvenile play fighting in rats: Insight into the experiences that facilitate the development of socio-cognitive skills By: Sergio M. Pellis, Vivien C. Pellis, and Lauren A. WilliamsInternational Journal of Comparative Psychology, 30(0) (2017) This study also delves into the importance of play fighting in early development and its impact on prefrontal cortex and brain development. We will not further explore this topic or reiterate what has already been discussed earlier. In this study, we examine two strains of rats: one characterized as highly playful and another as a low-playing strain during the juvenile period (Schneider et al., 2014; Schneider, Bindila, Schmahl, et al., 2016; Schneider, Pätz, Spanagel, et al., 2016). As adults, the Playful rats reared with Non-playful rats exhibited changes in pain threshold and displayed deficiencies in social cognition. Analysis of juvenile behavior revealed that Playful rats initiated numerous attacks, but these attacks were rarely reciprocated or initiated by the Non-playful rats. The Non-playful rats generally did not defend themselves against attacks, with only a few instances leading them to adopt wrestling-based defense tactics (Schneider, Bindila, Schmahl, et al., 2016; Schneider, Pätz, Spanagel, et al., 2016). When comparing these findings to the interactions between a nursing mother and her offspring, it becomes evident that mothers rarely engage in playful attacks or respond with playful defenses when attacked by their offspring. The young offspring prefer to play with their peers rather than their mother (Cramer, Thiels, & Alberts, 1990; Pellis & Pellis, 1997; Thiels, Alberts, & Cramer, 1990). There is a strong possibility that when a juvenile rat is reared with adult rats and lacks peers, they compensate by engaging in more play with the adults. However, the crucial factor is not merely the quantity of play with any rat, but rather the absence of wrestling and reciprocation in play with adults (Schneider, Bindila, Schmahl, et al., 2016; Schneider, Pätz, Spanagel, et al., 2016). When juvenile females were housed with adults or peers, there were no differences in nape attacks between the two groups, nor did the defensive behavior differ when attacked. Initially, this might suggest that the play experiences did not differ in the two groups. However, significant differences were found in the types of playful experiences. Adult females initiated only 13.3% of the playful attacks compared to the approximately 50% initiated by their counterparts in the juvenile pairs. Adult females were also only half as likely to employ defensive tactics that led to wrestling. For proper development to occur during the juvenile period, it is necessary for the partner being attacked to not only defend against the attacks but also engage in wrestling that allows for opportunities for role reversals. The present study suggests that a reduction of as little as 40% in playful wrestling may have negative consequences on development (Bell et al., 2010; Himmler, Pellis, & Kolb, 2013). Play fighting essentially provides an opportunity to acquire experience through cooperation and competition, ultimately fostering the development of good social skills. References
My conclusion As breeders, it is our utmost responsibility to ensure that the rats we rear develop into balanced and healthy adults. This responsibility begins well before the birth of any offspring, but in this article, we have solely focused on the post-birth responsibility during the early development of the pups we produce. We have discovered that juvenile rats require peers in order to develop properly. Failure to meet these requirements results in deficits in social, emotional, and cognitive abilities in adulthood. These deficits encompass an inability to interpret social cues, such as body language, and difficulties in interacting with other rats without resorting to defensive behavior. Additionally, rats reared without peers experience chronic stress, leading to a lower quality of life and reduced life expectancy. The decrease in play fighting observed around the 8th to 9th week does not signify a complete cessation of play fighting as the rats mature. Instead, we witness a shift in the tactics employed, which underscores the necessity for juveniles to have peers during their developmental stages to ensure proper development. As breeders, we may need to adjust our ethical practices to avoid depriving rats of essential play fighting or depriving them of age-matched peers during their development. If there is an insistence on selling single rats to individuals who already own rats, it may be advisable to ensure that the rat has reached sufficient maturity to develop properly without the need for a peer. However, this approach carries some risks since there are no studies available regarding this course of action. Some breeders suggest that rats should not be rehomed until they reach 12 weeks of age if they are to be placed in a home as a single rat (but with older rats present). However, upon considering these three studies, it becomes apparent that peers are better suited to be together throughout their lives, ensuring that they always have a rat at a similar developmental level. There is sufficient evidence to support the notion that breeders have valid reasons to insist on selling same-sexed pairs, even to homes with established groups.
0 Comments
|
❆
Alle
❆
Februar 2024
|