A wide array of species, from ants to humans, live or forage in groups. Shoaling – the formation of groups by fish – confers protection from predation and enhances foraging. However, little is known about the detailed characteristics or the dynamics of shoaling. Shoaling is a complex social interaction and a better understanding of its mechanisms and limitations would permit the study of natural and induced changes on social behavior generally in fish. Here, I present data on the shoaling characteristics of zebrafish (Danio rerio). Novel tracking techniques are used to extract detailed trajectories of all members of a free-swimming shoal of zebrafish. Multiple measures of shoaling – such as distributions of nearest neighbor distances, shoal polarizations, and speeds – are calculated, to better describe the subtleties of the behavior including, for the first time, the high resolution spatio-temporal dynamics of shoaling. In addition, a novel criterion is introduced to determine when and how individual fish or sub-groups leave the shoal. Comparisons are presented between the shoaling characteristics of three populations of zebrafish (LFWT, SFWT, AB) and between days and hours of repeated exposure to the same testing environment, demonstrating the gradual effects of habituation on shoaling. In addition, the effects of manipulating the number of fish in the shoal, hunger levels, and predation threat are also examined, lending empirical support to ecological theories on the adaptive functions of the behavior. Finally, the data are compared to two leading theoretical models of shoaling and a novel simulation approach is suggested. The data strongly suggest that various aspects of shoaling in zebrafish are constantly changing, complex, and flexible, representing a dynamic form of social cognition. The study of these characteristics sheds much-needed light on complex social interactions in this popular genetic model organism, which may eventually lead to a better understanding of social behaviors in other species, including our own.

This study examined perspectives of the trip to/from school and travel mode choice among parents who differed in socio-economic status (SES), and whose children attended schools located in different areas (i.e., urban vs. inner-suburban) across Toronto. Thirty-seven parents (20 active and 17 non-active travelers) of grade four to six students from four elementary schools (capturing diversity with respect to built environment and SES) participated in qualitative interviews after taking photos of their trip to/from school. Data were analyzed using thematic analysis linking the text and visual data. School travel was a habitual behaviour involving a 2-step parental decision-making process; these decisions were influenced by different factors. While escort decisions were dictated by safety concerns, the behavioural cost and reinforcing value of travel mode alternatives dictated mode choice. Strategies addressing these behavioural cost and reinforcing value factors may be helpful in making walking to/from school the quickest and most convenient choice.

This study examined perspectives of the trip to/from school and travel mode choice among parents who differed in socio-economic status (SES), and whose children attended schools located in different areas (i.e., urban vs. inner-suburban) across Toronto. Thirty-seven parents (20 active and 17 non-active travelers) of grade four to six students from four elementary schools (capturing diversity with respect to built environment and SES) participated in qualitative interviews after taking photos of their trip to/from school. Data were analyzed using thematic analysis linking the text and visual data. School travel was a habitual behaviour involving a 2-step parental decision-making process; these decisions were influenced by different factors. While escort decisions were dictated by safety concerns, the behavioural cost and reinforcing value of travel mode alternatives dictated mode choice. Strategies addressing these behavioural cost and reinforcing value factors may be helpful in making walking to/from school the quickest and most convenient choice.

A wide array of species, from ants to humans, live or forage in groups. Shoaling – the formation of groups by fish – confers protection from predation and enhances foraging. However, little is known about the detailed characteristics or the dynamics of shoaling. Shoaling is a complex social interaction and a better understanding of its mechanisms and limitations would permit the study of natural and induced changes on social behavior generally in fish. Here, I present data on the shoaling characteristics of zebrafish (Danio rerio). Novel tracking techniques are used to extract detailed trajectories of all members of a free-swimming shoal of zebrafish. Multiple measures of shoaling – such as distributions of nearest neighbor distances, shoal polarizations, and speeds – are calculated, to better describe the subtleties of the behavior including, for the first time, the high resolution spatio-temporal dynamics of shoaling. In addition, a novel criterion is introduced to determine when and how individual fish or sub-groups leave the shoal. Comparisons are presented between the shoaling characteristics of three populations of zebrafish (LFWT, SFWT, AB) and between days and hours of repeated exposure to the same testing environment, demonstrating the gradual effects of habituation on shoaling. In addition, the effects of manipulating the number of fish in the shoal, hunger levels, and predation threat are also examined, lending empirical support to ecological theories on the adaptive functions of the behavior. Finally, the data are compared to two leading theoretical models of shoaling and a novel simulation approach is suggested. The data strongly suggest that various aspects of shoaling in zebrafish are constantly changing, complex, and flexible, representing a dynamic form of social cognition. The study of these characteristics sheds much-needed light on complex social interactions in this popular genetic model organism, which may eventually lead to a better understanding of social behaviors in other species, including our own.

This thesis examines how natural variation in the foraging gene (for) of Drosophila melanogaster influences several learning and memory phenotypes in adult flies. These studies are undertaken using aversive olfactory associative conditioning paradigms. Novel approaches to standard Pavlovian conditioning paradigms are used in order to test hypotheses that were formulated based on what is known concerning movement- and feeding-related behaviour in the rover (forR) and sitter (fors) variants of for. The results show that natural variation in for, which is thought to have been under balancing selection in the wild, influences adult learning and memory traits appreciably. More specifically, forR flies, who are exposed to greater environmental heterogeneity than sitters, display retroactive interference. As might be expected from their foraging behaviour, rover responses are biased towards more recent learning events. Additionally, results indicate that individual performance in a learning task was affected by allelic variation in for and through pharmacological manipulations of PKG activity levels. Interestingly, in fors, but not forR, the acquisition of information was facilitated by social interaction (i.e. being in a group). In forR, but not in fors, the type of social interaction (being with other forR or with other fors) affected learning and memory. Also, naive individual forR flies tended to follow groups of conditioned fors but not groups of conditioned forR. In several other chapters, the thesis explores recent issues in behaviour genetics. In particular, the following concepts are explored: 1) the fruit fly as model for ecological and evolutionary studies; 2) cGMP-dependent protein kinase as a modifier of behaviour in disparate species; and 3) conservation of gene function in behaviour.

This thesis examines how natural variation in the foraging gene (for) of Drosophila melanogaster influences several learning and memory phenotypes in adult flies. These studies are undertaken using aversive olfactory associative conditioning paradigms. Novel approaches to standard Pavlovian conditioning paradigms are used in order to test hypotheses that were formulated based on what is known concerning movement- and feeding-related behaviour in the rover (forR) and sitter (fors) variants of for. The results show that natural variation in for, which is thought to have been under balancing selection in the wild, influences adult learning and memory traits appreciably. More specifically, forR flies, who are exposed to greater environmental heterogeneity than sitters, display retroactive interference. As might be expected from their foraging behaviour, rover responses are biased towards more recent learning events. Additionally, results indicate that individual performance in a learning task was affected by allelic variation in for and through pharmacological manipulations of PKG activity levels. Interestingly, in fors, but not forR, the acquisition of information was facilitated by social interaction (i.e. being in a group). In forR, but not in fors, the type of social interaction (being with other forR or with other fors) affected learning and memory. Also, naive individual forR flies tended to follow groups of conditioned fors but not groups of conditioned forR. In several other chapters, the thesis explores recent issues in behaviour genetics. In particular, the following concepts are explored: 1) the fruit fly as model for ecological and evolutionary studies; 2) cGMP-dependent protein kinase as a modifier of behaviour in disparate species; and 3) conservation of gene function in behaviour.

This work characterized the ability of mice to respond for conditioned reinforcement, a phenomenon that can be used to investigate neural substrates of incentive learning. In both C57Bl/6 and CD1 mice, a reward-associated stimulus acted as a conditioned reinforcer (CR). Responding was stable over multiple test days, enhanced in CD1 mice by the dopamine transporter (DAT) blocker methylphenidate, and was extinguished when responding no longer produced the CR. However, transgenic C57Bl/6 mice overexpressing DAT, which decreased striatal dopamine by 40% responded normally for CR. Therefore, these results suggest that mice can be used to study brain mechanisms of incentive motivation. However, the choice of mouse strain in this paradigm is important as outbred CD1 mice appeared more susceptible to a DAT blocker compared to the inbred C57Bl/6 strain. These results also suggest that selective responding for a CR remains intact in a chronically hypodopaminergic state.

This work characterized the ability of mice to respond for conditioned reinforcement, a phenomenon that can be used to investigate neural substrates of incentive learning. In both C57Bl/6 and CD1 mice, a reward-associated stimulus acted as a conditioned reinforcer (CR). Responding was stable over multiple test days, enhanced in CD1 mice by the dopamine transporter (DAT) blocker methylphenidate, and was extinguished when responding no longer produced the CR. However, transgenic C57Bl/6 mice overexpressing DAT, which decreased striatal dopamine by 40% responded normally for CR. Therefore, these results suggest that mice can be used to study brain mechanisms of incentive motivation. However, the choice of mouse strain in this paradigm is important as outbred CD1 mice appeared more susceptible to a DAT blocker compared to the inbred C57Bl/6 strain. These results also suggest that selective responding for a CR remains intact in a chronically hypodopaminergic state.

Ideomotor theory holds that motor plans producing action and the sensory effects of the actions are cognitively represented in a functionally similar way. The response-effect (R-E) association is considered bidirectional and automatic in nature. The current research project was designed to test the hypothesized bidirectional nature of R-E associations by determining if motor codes were activated following perception of an effect. The automaticity of motor code activation was investigated via TMS–induced motor evoked potentials (MEPs) following the presentation an after-effect. To this end, participants completed a training phase in which they learned a specific R-E association. During the testing phase, the effects were presented prior to the imperative and TMS stimuli. Behavioural results replicated previous research; participants preferred to execute the response associated with the presented effect. MEP data, however, did not support the initial hypothesis. These results are discussed with relation to ideomotor theory and experimental design.

Ideomotor theory holds that motor plans producing action and the sensory effects of the actions are cognitively represented in a functionally similar way. The response-effect (R-E) association is considered bidirectional and automatic in nature. The current research project was designed to test the hypothesized bidirectional nature of R-E associations by determining if motor codes were activated following perception of an effect. The automaticity of motor code activation was investigated via TMS–induced motor evoked potentials (MEPs) following the presentation an after-effect. To this end, participants completed a training phase in which they learned a specific R-E association. During the testing phase, the effects were presented prior to the imperative and TMS stimuli. Behavioural results replicated previous research; participants preferred to execute the response associated with the presented effect. MEP data, however, did not support the initial hypothesis. These results are discussed with relation to ideomotor theory and experimental design.