Marijuana use among American young adults is rising, and perceptions of harm are declining. Individual states continue to enact more lenient marijuana use and possession laws. Marijuana use is associated with many serious negative outcomes. Thus, marijuana use among this age group has become a public health concern. According to Primary Socialization Theory, parents exert their influence on youth behavior through the parent-adolescent bond and through communication. Previous researchers have identified parent-offspring communication about alcohol and tobacco as a potentially important target of prevention efforts. Little research has yet explored marijuana communication and its potential influence on use-related outcomes. This study sought to model the influence of the parent-adolescent bond and parent-offspring communication about marijuana on marijuana use and problems related to use. In order to model this influence, the Communication about Marijuana (CAM) measure first was developed. In Study 1, an initial pool of items tapping marijuana communication was tested using a sample of 18-25 year old (M=20.22) undergraduate students (N=433). Confirmatory factor analyses were performed to test the fit of the data to the proposed model. In Study 2, a revised CAM measure was tested with a second sample of 18-25 year old (M=20.40) undergraduate students (N=432). The final measure included four content topic factors comprising 9 items, and 3 descriptive items tapping communication context. Structural equation models were specified to model the parent-adolescent bond and marijuana communication content on student self-reported past year marijuana use and marijuana use problems. Results suggested that the parent-adolescent bond was protective on marijuana use frequency, while models including only the manifest variable parental support better fit the data with regard to marijuana use problems. Communication content was somewhat differentially related to outcomes. Discussions encouraging abstinence, offering advice on peer pressure and monitoring use were related to more frequent use. Communication that conveyed disappointment about marijuana use and offered advice about peer pressure and choosing non-using friends was related to more marijuana use problems. Positive relations between communication and use outcomes were unexpected, but may reflect reactive parenting. Results and implications for future research are discussed in the context of the extant literature.

La reconnaissance joue un rôle important dans les systèmes de communication animale et plusieurs modalités sensorielles sont impliquées à cette fin. Bien que la reconnaissance mère-jeune ait été largement étudiée, il y a un manque d'information sur la reconnaissance multimodale et l'importance relative des différentes modalités dans ce processus. Dans cette thèse, j'ai exploré la communication multimodale chez un mammifère colonial - le lion de mer Australien (Neophoca cinerea). La reconnaissance mère-jeune est connue pour être multimodale chez cette espèce, mais les processus sous-jacents de la reconnaissance olfactive et visuelle, ainsi que les interactions entre les indices acoustiques, visuels et olfactifs, et leurs contributions relatives restent inconnues. Des analyses chimiques ont permis de déterminer si les profils chimiques diffèrent selon le sexe et l'âge, les colonies et les régions corporelles des animaux. La présence de similarités chimiques entre la mère et son petit suggèrent que l'appariement des phénotypes pourrait être utilisé pour la reconnaissance olfactive. J'ai examiné le rôle des indices visuels lors de la reconnaissance mère-jeune et j'ai constaté que les indices visuels spécifiques à l'âge sont utilisés par les femelles pour affiner la recherche de leur petit dans la colonie. Les jeunes ont également la capacité de distinguer divers indices visuels, qui peuvent être utilisés pour identifier les différentes classes de congénères. Enfin, j’ai pu aussi déterminer comment les indices acoustiques, olfactifs et visuels sont utilisés de manière synergique dans le processus d’identification individuel, et les résultats sont interprété dans une perspective coûts-avantages pour démêler les pressions évolutives sur chaque composante de ce système de communication. Si les différents indices sensoriels ont la capacité de transmettre des informations en isolation, leur rôle peut être différent lorsque d'autres indices sensoriels sont présents. Les résultats de cette recherche fournissent des résultats sans précédent, contribuant à une meilleure compréhension de la reconnaissance mère-jeune chez les mammifères, ainsi que des règles générales de communication chez les vertébrés. / Recognition plays an important role in animal communication systems and individuals often employ different sensory modalities to enact this activity. Although recognition has been widely investigated, especially for mother-offspring interactions, there is a dearth of information about multimodal recognition and the relative importance and interactions of various sensory cues. In this thesis, I explored multimodal communication in a colonial mammal – the Australian sea lion (Neophoca cinerea). Communication during mother-pup reunions is known to be multimodal in this species, yet the underlying processes of olfactory and visual recognition, as well as the interactions between acoustic, visual and olfactory cues remain unclear. Through chemical analyses, I determined whether chemical profiles differ among sex and age classes, colonies, and body regions of animals. Chemical similarities between mothers and pups indicate that phenotype matching may be used by Australian sea lions for olfactory recognition. I examined the role of visual cues in mother-pup recognition and found that age-specific visual cues assist mothers to refine their search for their offspring in the colony. Pups are capable of distinguishing various visual cues that can be used in the assessment of conspecifics. Having provided baseline information about the role of sensory cues in isolation, I determined how acoustic, olfactory, and visual cues are used in a synergistic way to ensure accurate mutual recognition and then interpreted the results using a cost-benefit perspective to disentangle the evolutionary pressures on each component of this communication system. I showed that although cues have the ability to convey given information in isolation, their role may be different when other sensory cues are present. Furthermore, there is a mutual dependency in the communication system, where the limitations imposed on one participant of the dyad affect cue use by the other. These findings contribute to a better understanding of mammal mother-offspring recognition and communication mechanisms in vertebrates.