[2] Such faking would likely be favored through natural selection due to the ubiquity of conflicts of interests among living things creating situations in which the negative impacts on others are either not relevant or still worth the benefits to the signaler.
[21][22] Evidence in favor of hunting being a costly signal of beneficial qualities has primarily come from its valuation by group members and by the benefits good hunters enjoy.
[22][26] Material benefits are also seen with good hunters having been shown to have increased reproductive success, more political power, and more support for one’s kin in both times of illness and health.
[20][28][30] This is primarily due to the finding that young males (who are the age and sex class with the highest reproductive variance) take more risks than any other group in both experiments and observational data.
[28][30][31] By undertaking risky endeavors, males are thought to signal the previously mentioned qualities which may be directly related to one’s ability to provision and protect one’s family.
[29] However, traits like bravery and physical prowess may also be valued by cooperative partners due to their benefits in group-hunting and warfare, thereby increasing the potential audience for risk takers.
[16] Outside of these areas, both sexes are often suggested to benefit similarly in signaling pathogen resistance or a lack of harmful mutations due to their hypothesized importance over human evolutionary history.
[41][42][43][44] If defined as environmental modification lacking adaptive functions outside of sexual selection, art or art-like behavior has been observed in spiders, crabs, fish, and birds in addition to humans.
Creating art can require substantial amounts of time to learn the skills involved, find materials, and produce the work, all of which can prevent the individual from investing in other fitness enhancing tasks.
[42][43][44] For this reason, it may reliably signal information about one’s health, access to resources, or the relative absence of harmful mutations which might negatively impact one’s ability or overall condition.
[44] However, in humans, the potential for sex differences has been argued to not extend to artistic ability due to the commonality of long-term monogamous relationships resulting in the increased importance of mutual mate choice, something which favors females to invest more in sexual signals relative to other species.
[45] Although often accompanied by other signals, courtship duration on its own can create substantial opportunity costs as males cannot court other females at this time or invest in other fitness enhancing activities.
[48][49] In these situations, older siblings are expected to be favored due to being closer to reproduction and the fact that they have already survived infancy which has higher mortality rates than later childhood.
[56][55] However, neither may be mutually exclusive with signaling strategies due to the importance of reputation to cooperative relationships and the fact that sharing food that may not be worth defending still requires the effort to collect in the first place.
[57] However, the fact that feasts tend to only happen at particular times of the year and involve competition between groups has been used to suggest that they may primarily be forms of conspicuous consumption meant to signal one's overall quality or status.
[58] This results in a lack of obvious benefits for the donator who also incurs opportunity costs and the risk of mistakes and other negative outcomes, the threat of which may cause anxiety and other forms of psychological distress.
[8] Costly signals have also been suggested to be important for demonstrating commitment to both initiate and maintain dyadic relationships, with gift giving in particular receiving substantial attention as an individual strategy [62][63][64][65] and as a custom.
[66] Such approaches emphasize that the risk of defection from potential friends and romantic partners is particularly high at the start of relationships due to the amount of private information individuals have about their intentions to cooperate.
[69] This difference in perception makes it less likely an individual will find belief worth faking, with costlier practices expected to provide greater indications of one’s commitment.
[78] Suicide attempts may also increase the spread of the information from the signal due to their noteworthy nature, something which may be particularly important when the transgression was made against a group or puts cooperative relationships with those outside the aggrieved at risk.
[82] However, costly self-punishment was common in a study which forced participants to accidentally treat an anonymous partner unfairly, something which is consistent with the idea that apologies may also serve to maintain one’s reputation to a larger audience.
[83] Infant-directed song has been suggested to be a costly signal of parental attentiveness, something which is thought to particularly important when infants are too young to walk or correctly avoid dangers in their environment.
Whatever form the costs take, the benefit to the parent is suggested to be quicker and more reliable satiation of infant demands which would then allow greater for investment in other areas.
Conspicuous consumption refers to instances when individuals purchase luxury goods which provide little to no utility over less costly versions,[86] thereby prioritizing self-presentation over economic efficiency.
This is mainly seen in experiments which have manipulated the costs of items associated with males, with cars and clothing typical of higher classes having been found to be associated with increased probabilities of females entering into various types of romantic and sexual relationships and greater perceptions of attractiveness across multiple studies.
[54][57][91] As with conspicuous consumption, such signals are also often expected to provide information about one's underlying quality in addition to wealth, particularly relating to one's ability to acquire and maintain possession of resources.
Consistent with this reasoning, public displays of generosity may often decrease one's perceptions of cooperativeness or trustworthiness when they appear to be strategies meant to gain recognition or prestige.
[4][92] The bargaining model of depression suggests that throughout our evolutionary history individuals would have often faced instances of social adversity (e.g., abuse, the death of an important figure in one’s life, or the end of a romantic relationship) in which their fitness prospects depended primarily on responses from others.
[93][95] Although much of one’s illness symptoms are likely to come in the form of cues resulting from one’s susceptibilities to a pathogen or byproducts of one's defenses against it, such approaches suggest they may also be upregulated in order to better signal need.
[100][101] It may also be connected to lessened immune function based on studies reporting lower levels of salivary Immunoglobulin A in adult women following tears but not sadness alone.