Social Tests

Regardless of the interaction being voluntary or involuntary, almost every organism can be seen engaging in some form of social behavior. Social behaviors are adaptive in order to promote survivability and reproductive success. The most common social behavior is communication. In animals, most communication can be grouped as non-verbal. However, humans display both verbal and non-verbal communications. Communication between two or more individuals involves the production of the communication signals, its reception, and interpretation. Communication in organisms can be predominately divided into visual, auditory, chemical, and tactile communication. Apart from these categories of social modalities, some animals also utilize seismic, thermal, and electrocommunication. Different organisms rely on different modes of communication and their combinations.

Further classification of social behavior can be based on the type of interaction. When an interaction results in the benefit of all interacting parties, then it is a mutualistic behavior. Such interactions can also be seen between members of two different species. Altruistic interactions, on the other hand, results in the benefit of only the recipient, such as warning calls in birds. While these behaviors tend to be detrimental to the survival of the altruist, in some cases, the decision to indulge in these behaviors is calculated risk. Animals may engage in altruistic behaviors with the hope of future reciprocation. A common example of this is the reciprocal altruistic food sharing behavior among roost-mates that has been observed in vampire bats (Denault & McFarlane, 1995). However, not all social interactions are positive in nature. Animals can partake in both selfish and spiteful behaviors, with the latter behavior resulting in all interacting parties suffering the cost.

Highly social animals can be seen living in close-knit groups and engaging in behaviors that contribute to the maintenance of the group. Based on the degree of social interactions and cooperative living (excluding mating behaviors), animal sociality can be divided into isolatory, parasocial, and eusocial. Isolatory animals usually only partake in caring for their young (sub-social). In some cases, isolatory animals may occasionally cohabitate with other adults and young ones (solitary but social). Parasociality, on the other hand, is characterized by cooperative dwelling. Based on the responsibilities undertaken by the group members, para-sociality is further divided into communal, quasi-social, and semi-social communities. Communal animals care for their own offspring, while quasi-social animals share parental responsibilities in the nest. On the other hand, semi-social organisms not only share brood care responsibilities but also have a biological caste system in place. In addition to encompassing characteristics of semi-social organisms, eusocial societies have overlapping adult generations, cooperative care of young, and division of reproductive labor.

Social behaviors are influenced by a range of intrinsic and external factors in organisms. Studies of social behavior allow understanding of issues associated with animal conservation and wellbeing. Apart from understanding animal-centric issues and processes, animal social behavior also allows the generation of ideas that can be applied for betterment and development of human societies. Animal models are often used to understand and develop treatments for neuropsychiatric disorders and diseases that impact sociability in humans. Additionally, animal social behaviors also provide insights into the causes and evolution of human behaviors and the ideas that influence them.

Animal social assays tend to have multiple application scopes and are sometimes used in combination with other assays. While most behaviors in social assays can be recorded manually, it helps to have an automated tracking and recording system such as the Noldus EthoVision XT to assist with the observations.

2.1 Sociability Assays

Sociability assays are often used in the observation of general social behaviors and group-social interactions. Observed behaviors can vary depending on the context of the investigation.

Visual Burrow System

Developed by Bob Blanchard and Caroline Blanchard in the late 1980s, the Visual Burrow System mimics the natural environment of the rodents. This semi-naturalistic environment consists of an arena that is divided into an open arena and a burrow system. The apparatus allows observation of close to natural group social behaviors and can be extended to the observation of other behaviors, including maternal behaviors and aggressive social behaviors.

Zebrafish Sociability Chamber

The Zebrafish Sociability Chamber consists of a tank that has dividers creating a zig-zag path to the shoal chamber. The apparatus is usually used in the observation of social behaviors associated with the personality type of the subject. Additionally, the apparatus also provides insights into the shoaling preferences of the fish.

Drosophila Shallow Chamber

The Drosophila Shallow Chamber was designed by Simon and Dickinson (Simon, & Dickinson, 2010) to create a shallow volume of space that allows the flies to move in a single layer. This design makes the observation of social interactions between the flies easier to record and analyze.

2.2 Social Recognition Assays

The ability to recognize conspecifics plays a critical role in the formation of social relationships. Recognition allows distinction of familiars from unfamiliar conspecifics, which then allows reflecting of appropriate behavior. Social organization is also heavily affected by social recognition in animals. Apart from the context of mate-finding, social recognition contributes to other behaviors such as territory establishment, reciprocal altruism, and parent-offspring interactions (Mateo, 2004). In most animals, social recognition is predominantly based on olfactory cues, although visual and auditory cues may also be used.

Apart from applied animal behavior science, animal models of social recognition are usually used to assess short-term memory impairments and/or social cognition deficits that are often associated with neuropsychiatric disorders and other diseases. The time spent exploring a social stimulus is usually used as the parameter to assess social recognition.

SocioBox

The SocioBox was developed by Krueger-Burg and colleagues in 2016 in order to assess complex social recognition in rodents. The apparatus consists of a circular arena that is surrounded by an outer ring that provides individual housing for stimulus. The social recognition task involves exposing the subject to live conspecific held in the outer ring, followed by a recognition test where one of the stimulus conspecifics is replaced with an unfamiliar one.

2.3 Social Preference Assays

In their most basic application, social preference assays, assess the preference of the subject for a live social stimulus as opposed to an inanimate object. Social decision-making may be adaptive choices that are based on a variety of social and contextual factors. These assays also allow exploration of social preferences for unfamiliar versus familiar conspecific and even interspecies preferences. Additionally, these assays can also provide insights into the amount of effort the subject is ready to invest to receive a social reward. Based on the assay used, observed measures may include time spent in the vicinity of the social stimulus, time spent interacting with the social stimulus, and social behaviors directed towards the social stimulus.

Social Y-Maze

Social Y-Maze is an adaptation of the conventional Y-Maze and is used in the assessment of social preferences. The apparatus offers cages at the end of each goal arm to hold the stimuli used. The task is usually applied using a live unfamiliar conspecific in one arm and a dummy object in the other (Bitanihirwe, Peleg-Raibstein, Mouttet, Feldon, & Meyer, 2010)

Social Reward Chamber

The Social Reward Chamber is used to investigate the effects of social rewards on social preferences. The chamber is designed based Operant Social Preference task that offers the subject visual access to the stimulus held in the choice chambers. Additionally, the doors to the choice chambers are equipped to hold weights that force the subject to put in effort in order to access the reward.

Sociability Chamber

The Sociability Chamber is used in the assessment of social novelty preference. The apparatus consists of 3 chambers, with the central chamber serving as the start area and the lateral chambers as the choice chambers. The choice chambers come equipped with acrylic cages to hold stimulus, which prevents direct interactions as opposed to the interactions in the Social Reward Chamber. This helps minimize any aggressive behaviors between the animals used in the task.

2.4 Social Aggression and Dominance Assays

Some form of dominance hierarchy can often be observed in the social structure of animals that participate in communal living. In such groups, certain individuals are dominant over the others and tend to be given the first claim over resources and mates. Dominant behavior may also be observed between the interactions of members of different colonies. While not always, dominant behaviors can also include aggressive behaviors intended to assert dominance. In most cases, aggressive behaviors are usually responses to a perceived threat and are caused by fear. Aggressive behaviors can include either aggressive displays or actual physical harm to the other animal involved.

Tube Dominance

The Tube Dominance Test is predominantly used in assessing social dominance and social hierarchy in rodents. The apparatus consists of an open-ended tube with guillotine doors placed at its center to prevent interactions. Dominance is evaluated by placing opponents at either end of the tube and observing which of them forces the other to retreat.

Resident Intruder Chamber

Primarily used in the assessment of aggressive behaviors, the Resident Intruder Chamber can also be used to induce social stress. The apparatus is an opaque rectangular cage with a mesh roof and clear front wall. The general protocol involves habituating the resident subject (usually male) to the apparatus followed by the introduction of an unfamiliar conspecific (male) into the apparatus.

Mirror Biting Chamber

The Mirror Biting Chamber is a popular fish assay used to assess agnostic behaviors without the use of a large number of subjects. The apparatus is available in different variants, Elwood Mirror Biting Chamber, Pham et al. Mirror Biting Chamber, Balzarini et al. Mirror Biting Chamber, and Catellan et al. Mirror Biting Chamber; however, the underlying working principle remains the same. The tank(s) are equipped with mirror(s) which help provoke a strong, aggressive response in the subject without endangering them.

2.5 Social Emotions Assays

Social emotion assays are usually applied to emulate human emotions in animal models to assess treatments and therapies for psychiatric diseases and disorders. These assays also offer the opportunity to investigate whether animal behaviors are influenced by emotions or if animals are capable of emotions similar to humans.

Empathy Assay

The Empathy Assay combines a two-chamber Fear Conditioning Chamber to evaluate the empathetic response of the subject to observing a familiar or unfamiliar conspecific receiving shocks (Jeon & Shin, 2011). The protocol is applied in two phases, a training phase, and a retention phase. Behaviors indicating empathy include freezing and the number of fecal droppings.

Water E-Maze

The Water E-Maze combines aspects of the Morris Water Maze and social preference to evaluate the empathetic motivation of the subject to conspecific distress. The subject is usually given a choice to help escape one of the two live conspecifics held in the choice chambers. In order to address if the social preference of the subject can be affected by empathy, one of the stimulus conspecifics is placed in a pool of water in the goal chamber.

Social Interactions Test

The Social Interaction Test is usually used to assess social novelty. The apparatus is composed of an Open-Field with a perforated acrylic cage situated at the center of one of the arena wall. The test uses a similar concept as the Social Defeat Chamber that is often used to induce social stress to assess the change in the sociability of the stressed subject (Berton et al., 2006).

Social interactions and sociability greatly contribute to the quality of life in humans. Human sociability evolves in phases (aging) and is influenced by factors that are intrinsic, such as emotions, and external such as the environment an individual is raised in. The variety of influential factors make understanding human social psychology a difficult process. Understanding of human sociability is usually based on empirical investigations through surveys, observational research, and correlational methods (For digital healthcare tools visit Qolty). While these do provide relevant insights; emotions, and social understandings of humans are subjective in nature. Additionally, investigators own bias may also influence the data apart from other experimental factors that cannot be controlled and kept consistent.

With the advancement of technology, more researchers are opting for virtual reality-based investigations that eliminate few of the ethical concerns associated with human-based research (For virtual reality tools visit SimianLabs). Virtual reality environments offer researchers great control over the simulation and the variables of social interactions. This then allows the creation of experiments that are more specific and controlled across all participants. Human virtual reality experiments also allow simulation of difficult social scenarios, such as racist social behaviors, and dangerous situations, such as crowd behavior in escaping a burning building. For human virtual reality experiments, click here.

Animal models provide great assistance when it comes to drug testing and the development of treatments for sociability and social cognitive impairments associated with many neuropsychiatric disorders and diseases. It is important that efforts be made to perform all investigations as ethically as possible. The following are few guidelines for animal-based experiments,

• Social isolation for some animals can be extremely stressful and thus should be kept to the required minimum for an experiment.
• Animals should be habituated to handling to minimize the effects of handling stress.
• Experiments that involve aggressive interactions should be carefully monitored to prevent injury to the animals involved.
• Animals should be habituated to restraint to prevent unnecessary fear and stress. (For restraints click here).
• Apparatuses should be cleaned as necessary to prevent any lingering olfactory cue from influencing the subject behavior.

Apart from the above guidelines, efforts should be made to ensure the overall wellbeing of the animals in the laboratory. Animals should not be subjected to unnecessary stress or mishandling at any time.

In human experiments and research, the following are few guidelines that should be followed,

• Explicit consent of the participants should be obtained prior to testing.
• Experiments should be age-appropriate and take into consideration all medical factors.
• Safety and wellbeing of the participants should be prioritized above all.
• Experiments that involve potential triggering set-ups should be carefully created so as not to overwhelm or stress the participant.
• Appropriate measures should be taken when using virtual reality for experimentation.

Researching animal sociability and associated behaviors helps in conservation efforts and improving animal welfare. Animal models contribute to technological development, providing insights into ways communication can be managed. Further, they allow the overcoming of ethical concerns associated with human experimentation. Modeling of diseases and disorders in animals makes it possible to explore different approaches of understanding and treating social impairments in humans. Despite the fact that different animal models have provided us with relevant insights into the possible process involved in the development of sociability behaviors, they do not serve as an exact model of human emotions and behaviors.

1. Allport, G. W (1985). “The historical background of social psychology.” In Lindzey, G; Aronson, E (eds.). The Handbook of Social Psychology. New York: McGraw Hill.p.5
2. Amdam, G. V. & Hovland, A. L. (2011) Measuring Animal Preferences and Choice Behavior. Nature Education Knowledge, 3(10):74
3. Berton, O., McClung, C. A., Dileone, R. J., Krishnan, V., Renthal, W., Russo, S. J., … , Nestler, E. J. (2006). Essential role of BDNF in the mesolimbic dopamine pathway in social defeat stress. Science;311(5762):864-8.
4. Bitanihirwe, B. K., Peleg-Raibstein, D., Mouttet, F., Feldon, J., & Meyer, U. (2010). Late Prenatal Immune Activation in Mice Leads to Behavioral and Neurochemical Abnormalities Relevant to the Negative Symptoms of Schizophrenia. Neuropsychopharmacology, 35(12), 2462–2478. doi:10.1038/npp.2010.129
5. Blanchard, R. J., & Blanchard, D. C. (1989). Antipredator defensive behaviors in a visible burrow system. Journal of Comparative Psychology, 103(1):70-82.
6. Denault, L. K, & McFarlane, D.A. (1995). Reciprocal altruism between male vampire bats, Desmohs votundus. Animal Behavior, 49, 855-856
7. Gillam, E. (2011) An Introduction to Animal Communication. Nature Education Knowledge 3(10):70
8. Jeon, D., & Shin, H. S. (2011). A mouse model for observational fear learning and the empathetic response.Current Protocols in Neuroscience, Chapter 8:Unit 8.27. doi: 10.1002/0471142301.ns0827s57.
9. Krueger-Burg, D., Winkler, D., Mitkovski, M., Daher, F., Ronnenberg, A., Schlüter, O. M., … Ehrenreich, H. (2016). The SocioBox: A Novel Paradigm to Assess Complex Social Recognition in Male Mice. Frontiers in Behavioral Neuroscience, doi:10.3389/fnbeh.2016.00151
10. Mateo, J. M. (2004). Recognition systems and biological organization: The perception component of social recognition. Annales Zoologici Fennici, 41: 729-745.
11. McGlynn, T. (2010). How Does Social Behavior Evolve? Nature Education Knowledge 3(10):69
12. Robinson, G. E., Fernald, R. D., & Clayton, D. F. (2008). Genes and social behavior. Science, 322(5903):896-900. doi: 10.1126/science.1159277.
13. Simon, J. C., & Dickinson, M. H. (2010). A new chamber for studying the behavior of Drosophila.PLoS One. 5(1), e8793. DOI: 10.1371/journal.pone.0008793