Attention and Decision-making: How allocation of attention to decision alternatives influences the final choice

Research in the area of decision-making has acknowledged the role of attention in arriving to the final choice. The gaze cascade model suggests a bidirectional relationship between attention and preference – as we begin to orient towards the preferred option, such orienting further increases preference. The attentional drift diffusion model suggests that attention can amplify evidence; however, attention varies randomly between the options. This thesis aims to investigate the role of attention in decision-making from two perspectives: the decision-making models that suggest that attention can bias evidence, and the perceptual learning literature, which has investigated how exposure can affect discrimination between similar stimuli. Chapter 1 investigates whether attention can bias preference. We used a design in which some of the decision options are paired with reward-related stimuli. As we expected such stimuli to capture attention, we aimed to investigate whether such attentional capture can bias the choice. Our results showed a choice bias over short exposure times but not with self-paced decisions. Chapter 2 investigates whether attention is biased towards the eventually chosen option. Using a perceptual decision task, results showed that participants spend longer attending to the chosen option; however, the result did not replicate when the task required participants to press a key to inspect each option. Chapters 3 and 4 investigate the intermixed-blocked exposure effect, a finding that shows how the manner of exposure to stimuli can affect the ease of discrimination between them. Specifically, alternating exposure to two stimuli facilitates discrimination relative to a case in which all exposures to one precede all exposures to the other. Chapter 3 investigates the inhibitory relationships account, which suggests that alternating exposure to stimuli allows for inhibitory relationships to form between their unique features, such that the presence of one signals the absence of the other. However, our experiments showed no evidence for this account. Chapter 4 investigates a memory account of the intermixed-blocked exposure effect - the account suggests that alternating exposure between two stimuli means that the unique feature of each, shown at every other exposure, requires more processing than the rest of the stimulus. However, our results showed that increasing the delay between exposures to the unique features had no effect on discrimination accuracy

Experimental evolution of herbicide resistance in chlamydomonas reinhardtii

Our understanding of the evolutionary dynamics of selection for herbicide resistance is limited by the time and space required to conduct meaningful selection experiments in higher plants. This constrains the study of the dynamics of resistance evolution predominantly to mathematical models. The primary goal of this thesis was to overcome these limitations, and to study the evolutionary phenomena underpinning several management strategies. To do so, a series of experimental evolution studies were conducted using Chlamydomonas reinhardtii, a single-­‐cell green chlorophyte susceptible to a range of commercial herbicides. In particular, this thesis explored the impact of herbicide sequences, rotations and mixtures, as well the impact of herbicide dose, on evolution of resistance. Applying herbicides in sequence allowed the study of the impact of environmental perturbation on the dynamics of resistance and the associated fitness costs, finding more rapid selection for resistance to a second and third mode of action in some populations. Cycling between herbicides creates conditions of temporal environmental heterogeneity, the outcomes of which are not easily predictable as resistance was slowed down in some cycling regimes, while in others it accelerated the evolution of resistance or gave rise to cross-­‐resistance. Herbicide mixtures are a management strategy relying on increases in environmental complexity to provide better control of resistance. The results presented show that mixtures were effective at slowing the evolution of resistance when all mixture components were used at fully effective doses, while low doses of mixtures accelerated resistance evolution and led to more cross-­‐resistance. Finally, modifications of the applied herbicide dose allowed the study of local adaptation along an environmental gradient, where the differences in outcomes based on the specific herbicides used were again evident. Overall, the work presented here uses applied scenarios to study the underlying evolutionary phenomena, in order to feed back into the applied thinking

Herbicide mixtures at high doses slow the evolution of resistance in experimentally evolving populations of Chlamydomonas reinhardtii

The widespread evolution of resistance to herbicides is a pressing issue in global agriculture. Evolutionary principles and practices are key to the management of this threat to global food security. The application of mixtures of herbicides has been advocated as an anti-resistance strategy, without substantial empirical support for its validation. We evolved experimentally populations of the unicellular green chlorophyte, Chlamydomonas reinhardtii, to minimum inhibitory concentrations (MICs) of single-herbicide modes of action and to pair-wise and three-way mixtures between different herbicides at various total combined doses. Herbicide mixtures were most effective when each component was applied at or close to its MIC. When doses were high, increasing the number of mixture components was also effective in reducing the evolution of resistance. Employing mixtures at low combined doses did not retard resistance evolution, even accelerating the evolution of resistance to some components. At low doses, increasing the number of herbicides in the mixture tended to select for more generalist resistance (cross-resistance). Our results reinforce findings from the antibiotic resistance literature and confirm that herbicide mixtures can be very effective for resistance management, but that mixtures should only be employed where the economic and environmental context permits the applications of high combined doses

Strange but true: Corroboration and base rate neglect

How do we deal with unlikely witness testimonies? Whether in legal or everyday reasoning, corroborative evidence is generally considered a strong marker of support for the reported hypothesis. However, questions remain regarding how the prior probability, or base rate, of that hypothesis interacts with corroboration. Using a Bayesian network model, we illustrate an inverse relationship between the base rate of a hypothesis, and the support provided by corroboration. More precisely, as the base rate of hypothesis becomes more unlikely (and thus there is lower expectation of corroborating testimony), each piece of confirming testimony provides a nonlinear increase in support, relative to a more commonplace hypothesis-assuming independence between witnesses. We show across 3 experiments that lay reasoners consistently fail to account for this impact of (rare) base rates in both diagnostic and intercausal reasoning, resulting in substantial underestimation in belief updating. We consider this a novel demonstration of an inverted form of base rate neglect. We highlight the implications of this work for any scenario in which one cannot assume the confirmation or disconfirmation of a reported hypothesis is uniform.

Adaptation at different points along antibiotic concentration gradients

Antibiotic concentrations vary dramatically in the body and the environment. Hence, understanding the dynamics of resistance evolution along antibiotic concentration gradients is critical for predicting and slowing the emergence and spread of resistance. While it has been shown that increasing the concentration of an antibiotic slows resistance evolution, how adaptation to one antibiotic concentration correlates with fitness at other points along the gradient has not received much attention. Here, we selected populations of Escherichia coli at several points along a concentration gradient for three different antibiotics, asking how rapidly resistance evolved and whether populations became specialized to the antibiotic concentration they were selected on. Populations selected at higher concentrations evolved resistance more slowly but exhibited equal or higher fitness across the whole gradient. Populations selected at lower concentrations evolved resistance rapidly, but overall fitness in the presence of antibiotics was lower. However, these populations readily adapted to higher concentrations upon subsequent selection. Our results indicate that resistance management strategies must account not only for the rates of resistance evolution but also for the fitness of evolved strains

The relation between parental supervision and conduct on the internet

Cilj ovog istraživanja bio je ispitati odnos roditeljskog nadzora i spola sudionika sa nekim ponašanjima na internetu. U istraživanju je sudjelovalo 388 učenika četvrtih razreda osnovnih škola u Republici Hrvatskoj. Rezultati pokazuju kako djeca češće percipiraju visoku razinu roditeljskog nadzora. Učenici koji percipiraju višu razinu roditeljskog nadzora provode više vremena dnevno u dopisivanju s prijateljima i u traženju zanimljivih podataka, češće pronalaze motivaciju za pristupanje internetu u traženju informacija vezanih za školu i druženju te češće objavljuju sadržaje na društvenim mrežama od učenika koji percipiraju nižu razinu roditeljskog nadzora. Prilikom ispitivanja spolnih razlika utvrđeno je kako dječaci češće izražavaju kako imaju otvoren Facebook profil, provode više vremena na internetu radnim danom i vikendom od djevojčica te češće igraju igrice, objavljuju postove i traže zanimljive podatke. Osim toga, češće pronalaze motivaciju za pristup internetu u odlaganju dosade i želji da ne budu drugačiji od drugih, a i češće navode kako ne mogu bez interneta, dok djevojčice češće pristupaju internetu u obrazovne svrhe. Rezultati su pokazali kako dječaci češće objavljuju različite sadržaje na društvenim mrežama i češće otkrivaju osobne informacije na Facebook-u, dok u percipiranoj razini roditeljskog nadzora nisu utvrđene spolne razlike. Ovi podaci mogu pridonijeti boljem razumijevanju uloge roditelja u korištenju interneta kod djece.The aim of this study was to examine the relationship between parental control and gender in some behaviors on Internet. The participants were 388 fourth-grade primary school students in the Republic of Croatia. The results indicated that children are more likely to perceive high level of parental control. The students who perceive a higher level of parental control spend more time in correspondence with friends and in search of interesting informations, more often find the motivation to access the Internet in finding school related informations and socializing, often publish content on social networks unlike students who perceive a lower level of parental control. When examining gender differences, it was found that boys more often say that they have an open Facebook profile, spend more time on the Internet on weekday and weekend, play games, publish posts and look for interesting information. In addition, the boys more often find the motivation for Internet access in ending boredom and the desire not to be different from others and more often they state they can not do without the Internet while girls are more likely to access the Internet in educational purposes. Also, the results indicated that the boys frequently post more diverse content on social networks and reveal personal information on Facebook. There are no gender differences in perceived level of parental control. These data can contribute to a better understanding of the role of parents in using the Internet in children

The relation between parental supervision and conduct on the internet

Cilj ovog istraživanja bio je ispitati odnos roditeljskog nadzora i spola sudionika sa nekim ponašanjima na internetu. U istraživanju je sudjelovalo 388 učenika četvrtih razreda osnovnih škola u Republici Hrvatskoj. Rezultati pokazuju kako djeca češće percipiraju visoku razinu roditeljskog nadzora. Učenici koji percipiraju višu razinu roditeljskog nadzora provode više vremena dnevno u dopisivanju s prijateljima i u traženju zanimljivih podataka, češće pronalaze motivaciju za pristupanje internetu u traženju informacija vezanih za školu i druženju te češće objavljuju sadržaje na društvenim mrežama od učenika koji percipiraju nižu razinu roditeljskog nadzora. Prilikom ispitivanja spolnih razlika utvrđeno je kako dječaci češće izražavaju kako imaju otvoren Facebook profil, provode više vremena na internetu radnim danom i vikendom od djevojčica te češće igraju igrice, objavljuju postove i traže zanimljive podatke. Osim toga, češće pronalaze motivaciju za pristup internetu u odlaganju dosade i želji da ne budu drugačiji od drugih, a i češće navode kako ne mogu bez interneta, dok djevojčice češće pristupaju internetu u obrazovne svrhe. Rezultati su pokazali kako dječaci češće objavljuju različite sadržaje na društvenim mrežama i češće otkrivaju osobne informacije na Facebook-u, dok u percipiranoj razini roditeljskog nadzora nisu utvrđene spolne razlike. Ovi podaci mogu pridonijeti boljem razumijevanju uloge roditelja u korištenju interneta kod djece.The aim of this study was to examine the relationship between parental control and gender in some behaviors on Internet. The participants were 388 fourth-grade primary school students in the Republic of Croatia. The results indicated that children are more likely to perceive high level of parental control. The students who perceive a higher level of parental control spend more time in correspondence with friends and in search of interesting informations, more often find the motivation to access the Internet in finding school related informations and socializing, often publish content on social networks unlike students who perceive a lower level of parental control. When examining gender differences, it was found that boys more often say that they have an open Facebook profile, spend more time on the Internet on weekday and weekend, play games, publish posts and look for interesting information. In addition, the boys more often find the motivation for Internet access in ending boredom and the desire not to be different from others and more often they state they can not do without the Internet while girls are more likely to access the Internet in educational purposes. Also, the results indicated that the boys frequently post more diverse content on social networks and reveal personal information on Facebook. There are no gender differences in perceived level of parental control. These data can contribute to a better understanding of the role of parents in using the Internet in children

Kritika kapitala u savremenoj umjetnosti

Glavni predmet ove doktorske disertacije je pojava i razvoj kritike kapitala u savremenoj postmedijskoj umjetnosti kojom se nastoji pružiti otpor savremenom kapitalizmu zbog paradoksa, društvenih kriza i konflikata, nejednakosti i prekarnosti koje on, tokom svojih globalističkih i eksploatacijskih tendencija, proizvodi. Time se nastoji ukazati na neophodno rješavanje dileme o tome da li naš svijet treba da predvodi moć kapitala ili znanje, pri čemu se kapital i ekonomija ne posmatraju sa stanovišta ekonomske teorije već iz diskursa teorije savremene umjetnosti. Osnovni ciljevi ogledaju se u izučavanju diskursa savremenosti, diskurzivnom proučavanju kritičkog umjetničkog otpora prema represivnim metodama politike i ekonomije, ukazivanju na značaj teorijskog i istraživačkog postupka u savremenoj postmedijskoj umjetnosti, analizi istorijskih okolnosti i društveno-kulturalne i geopolitičke stvarnosti kao preduslova za nastanak kritičke umjetnosti koja ne negira svoj politički i društveni angažman u nastojanju stvaranja i održavanja inkluzivnijeg i ravnopravnijeg društva. Uvodni dio prikazuje metodološki aspekt disertacije koji stavlja naglasak na komparativnu analizu i dedukciju koja iz nje proizilazi, kao i predlog hipoteza koje se ovom disertacijom razvijaju. Prvo poglavlje bavi se prikazom i komparacijom teorija savremenog kapitala i kapitalizma. Drugo poglavlje obrazlaže pojavu kritike kapitala u teoriji umjetnosti. Treće poglavlje prikazuje domete i karakter kritike kapitala u savremenoj umjetnosti. Četvrto poglavlje tumači fenomen boje u novoj i smjeloj ulozi kritike kapitala. Peto poglavlje analizira pojam forme u umjetnosti koji se može posmatrati i sa kritičkog aspekta. Šesto poglavlje posmatra kritiku kapitala iz diskursa kritike modernosti i antropocena. Zaključak objedinjuje ponuđene hipoteze o aktivnom kritičkom odnosu savremene umjetnosti prema globalnom kapitalizmu, o umjetnosti kao socijalnoj strategiji odgovornoj prema društvu, i o umjetnosti kao jeziku otpora prema dominantnim oblicima moći putem diskurzivnog i epistemološkog istraživanja, i upućuje na njegovu istorijsku, društvenu i naučnu opravdanost i primjenljivost po pitanju daljeg razvoja i uloge umjetnosti u svijetu

On the mechanistic nature of epistasis in a canonical cis -regulatory element

Understanding the relation between genotype and phenotype remains a major challenge. The difficulty of predicting individual mutation effects, and particularly the interactions between them, has prevented the development of a comprehensive theory that links genotypic changes to their phenotypic effects. We show that a general thermodynamic framework for gene regulation, based on a biophysical understanding of protein-DNA binding, accurately predicts the sign of epistasis in a canonical cis-regulatory element consisting of overlapping RNA polymerase and repressor binding sites. Sign and magnitude of individual mutation effects are sufficient to predict the sign of epistasis and its environmental dependence. Thus, the thermodynamic model offers the correct null prediction for epistasis between mutations across DNA-binding sites. Our results indicate that a predictive theory for the effects of cis-regulatory mutations is possible from first principles, as long as the essential molecular mechanisms and the constraints these impose on a biological system are accounted for

Epistatic Interactions in the Arabinose Cis-Regulatory Element

Changes in gene expression are an important mode of evolution; however, the proximate mechanism of these changes is poorly understood. In particular, little is known about the effects of mutations within cis binding sites for transcription factors, or the nature of epistatic interactions between these mutations. Here, we tested the effects of single and double mutants in two cis binding sites involved in the transcriptional regulation of the Escherichia coli araBAD operon, a component of arabinose metabolism, using a synthetic system. This system decouples transcriptional control from any posttranslational effects on fitness, allowing a precise estimate of the effect of single and double mutations, and hence epistasis, on gene expression. We found that epistatic interactions between mutations in the araBAD cis-regulatory element are common, and that the predominant form of epistasis is negative. The magnitude of the interactions depended on whether the mutations are located in the same or in different operator sites. Importantly, these epistatic interactions were dependent on the presence of arabinose, a native inducer of the araBAD operon in vivo, with some interactions changing in sign (e.g., from negative to positive) in its presence. This study thus reveals that mutations in even relatively simple cis-regulatory elements interact in complex ways such that selection on the level of gene expression in one environment might perturb regulation in the other environment in an unpredictable and uncorrelated manner