Quantitative genetic analysis of attractiveness of yeast products to Drosophila.

An attractive perfume is a complex mixture of compounds, some of which may be unpleasant on their own. This is also true for the volatile combinations from yeast fermentation products in vineyards and orchards when assessed by Drosophila. Here, we used crosses between a yeast strain with an attractive fermentation profile and another strain with a repulsive one and tested fly responses using a T-maze. QTL analysis reveals allelic variation in four yeast genes, namely PTC6, SAT4, YFL040W, and ARI1, that modulated expression levels of volatile compounds [assessed by gas chromatography-mass spectrometry (GC-MS)] and in different combinations, generated various levels of attractiveness. The parent strain that is more attractive to Drosophila has repulsive alleles at two of the loci, while the least attractive parent has attractive alleles. Behavioral assays using artificial mixtures mimicking the composition of odors from fermentation validated the results of GC-MS and QTL mapping, thereby directly connecting genetic variation in yeast to attractiveness in flies. This study can be used as a basis for dissecting the combination of olfactory receptors that mediate the attractiveness/repulsion of flies to yeast volatiles and may also serve as a model for testing the attractiveness of pest species such as Drosophila suzukii to their host fruit.

Choice-induced tasting. Evaluating the effect of choice on children's acceptance of an unfamiliar vegetable.

Children's vegetable intake is in general below recommendations. It is known that self-selection of vegetables out of multiple options can increase intake in children. However, it is not clear if this effect is driven by a pre-existing preference for the selected food, or purely by having a choice. Allowing children to choose could create a positive bias and endorse feelings of autonomy, which could increase acceptance of the food and promote intake. The aim of the present pre-registered study was to investigate the effect of choice in promoting the acceptance of an unfamiliar vegetable during a blind-choice task. Children aged 4-5 years old (n = 161) were randomly assigned to the choice or no-choice condition. Each child was presented with three closed cups, containing a vegetable. The children were unaware that the cups contained the same vegetable, a piece of raw celeriac. In the choice condition, the children were able to choose a cup themselves whereas in the no-choice condition, the experimenter made the decision. We hypothesized that children in the choice condition would show more acceptance of the vegetable compared to children in the no-choice condition and that higher levels of picky eating would lead to less vegetable acceptance. The results demonstrated that choice indeed significantly increased vegetable acceptance (4.7 ± 1.7 versus 4.0 ± 1.9 on a 6-point scale), irrespective of pickiness in eating. In addition, picky children showed less acceptance of the vegetable compared to non-picky children. The results of this study imply that choice is an important factor in promoting unfamiliar vegetable intake in young children. Including children in the decision process may be a practical strategy for educators and caregivers to increase children's vegetable intake.

Neurochronometry of choice-induced preference changes: when do preferences actually change?

According to cognitive dissonance theory, a discrepancy between preferences and actions may lead to the revaluation of preferences, increasing preference for the chosen options and decreasing for the rejected options. This phenomenon is known as the spreading of alternatives (SoA), which results in a choice-induced preference change (CIPC). Previous neuroimaging studies have identified several brain regions that play a role in cognitive dissonance. However, the neurochronometry of the cognitive mechanisms underlying CIPC is a topic of debate. In other words, does it occur during the difficult choice, immediately after the choice, or when people encounter the options again? Furthermore, it remains unclear what is the exact time point, relative to the onset of facing options, either within the choice or after it, when the attitudes start to be revised. We argue that applying online protocols of transcranial magnetic stimulation (TMS), during or immediately after the choice process, could be the most efficient way to better understand the temporal dynamics of the SoA effect. TMS allows for achieving high temporal and spatial resolution, modulating the activity of areas of interest, and examining the causal relationships. Besides, unlike the offline TMS, the online instrument allows tracking of the neurochronometry of attitude change, by varying stimulation onsets and durations with respect to the option stimuli. Based on scrupulous analysis of previous findings, employing online TMS studies of conflict monitoring, cognitive control, and CIPC neuroimaging results, we conclude that the use of online TMS is critical to examine the neurochronometry of CIPC.

Everything is connected: Inference and attractors in delusions.

Delusions are, by popular definition, false beliefs that are held with certainty and resistant to contradictory evidence. They seem at odds with the notion that the brain at least approximates Bayesian inference. This is especially the case in schizophrenia, a disorder thought to relate to decreased - rather than increased - certainty in the brain's model of the world. We use an active inference Markov decision process model (a Bayes-optimal decision-making agent) to perform a simple task involving social and non-social inferences. We show that even moderate changes in some model parameters - decreasing confidence in sensory input and increasing confidence in states implied by its own (especially habitual) actions - can lead to delusions as defined above. Incorporating affect in the model increases delusions, specifically in the social domain. The model also reproduces some classic psychological effects, including choice-induced preference change, and an optimism bias in inferences about oneself. A key observation is that no change in a single parameter is both necessary and sufficient for delusions; rather, delusions arise due to conditional dependencies that create 'basins of attraction' which trap Bayesian beliefs. Simulating the effects of antidopaminergic antipsychotics - by reducing the model's confidence in its actions - demonstrates that the model can escape from these attractors, through this synthetic pharmacotherapy.

How decisions and the desire for coherency shape subjective preferences over time.

Recent findings suggest a bidirectional relationship between preferences and choices such that what is chosen can become preferred. Yet, it is still commonly held that preferences for individual items are maintained, such as caching a separate value estimate for each experienced option. Instead, we propose that all possible choice options and preferences are represented in a shared, continuous, multidimensional space that supports generalization. Decision making is cast as a learning process that seeks to align choices and preferences to maintain coherency. We formalized an error-driven learning model that updates preferences to align with past choices, which makes repeating those and related choices more likely in the future. The model correctly predicts that making a free choice increases preferences along related attributes. For example, after choosing a political candidate based on trivial information (e.g., they like cats), voters' views on abortion, immigration, and trade subsequently shifted to match their chosen candidate.

Increased Preference and Value of Consumer Products by Attentional Selection.

It is usually assumed that individuals base their preferences for products or other items on the utility or value associated with the items. However, there is evidence that the attentional selection of an item alone already modulates the preference for that item. This has been shown, for instance, in preference choice tasks with unknown consumer products. Products that served as targets in a preceding visual search task were preferred to former distractor products. However, it is unclear whether such effects can also be observed when individuals have pre-existing attitudes toward products and whether attentional selection can change the perceived value of products. Hence, the aim of the present research was to replicate the attentional-selection effect on choice with known products and examine whether selective attention affects the perceived value of products beyond choosing the items. In two experiments, we replicated the attentional-selection effect on item preference in a choice task. Items that had served as targets in the search task were preferred to previous distractors. Introducing a response deadline in the preference-choice task in Experiment 2 did not further increase this effect. However, the value of former targets was rated higher than that of former distractors. Hence, the present results indicate that attentional selection not only affects preference choices but can also increase the value of attended and selected items.

From neuronal to psychological noise - Long-range temporal correlations in EEG intrinsic activity reduce noise in internally-guided decision making.

Our personal internal preferences while making decisions are usually consistent. Recent psychological studies, however, show observable variability of internal criteria occurs by random noise. The neural correlates of said random noise - an instance of 'psychological noise' - yet remain unclear. Combining simulation, behavioral, and neural approaches, our study investigated the psychological and neural correlates of such random noise in our internal criteria during decision making. We applied well-established decision-making tasks which relied on either internal criteria - occupation choice task as internally-guided decision making (IDM) - or external criteria - salary judgment task as externally-guided decision making (EDM). Subjects underwent EEG for resting state and task-evoked activity during IDM and EDM. We measured resting state long-range temporal correlation (LRTC) in the alpha frequency range as the index of neuronal noise. Based on our simulation, we identified a measure of psychological noise (as distinguished from true preference change) in IDM. The main finding shows that the indices for psychological noise are directly related to frontocentral LRTC in the alpha range. Higher degrees of frontocentral LRTC, which index lower neuronal noise, were related to lower degrees of psychological noise during IDM. This was not found during EDM. Resting state LRTC was also related to task-evoked activity, such as conflict-related negativity, during IDM only. Taken together, our data demonstrate, for the first time, the direct relationship between neuronal noise in the brain's intrinsic activity and psychological noise in the internal criteria of our decision making.

Hard Decisions Shape the Neural Coding of Preferences.

Hard decisions between equally valued alternatives can result in preference changes, meaning that subsequent valuations for chosen items increase and decrease for rejected items. Previous research suggests that this phenomenon is a consequence of cognitive dissonance reduction after the decision, induced by the mismatch between initial preferences and decision outcomes. In contrast, this functional magnetic resonance imaging and eye-tracking study with male and female human participants found that preferences are already updated online during the process of decision-making. Preference changes were predicted from activity in left dorsolateral prefrontal cortex and precuneus while making hard decisions. Fixation durations during this phase predicted both choice outcomes and subsequent preference changes. These preference adjustments became behaviorally relevant only for choices that were remembered and were in turn associated with hippocampus activity. Our results suggest that preferences evolve dynamically as decisions arise, potentially as a mechanism to prevent stalemate situations in underdetermined decision scenarios.SIGNIFICANCE STATEMENT Most theories of decision-making assume that we always choose the best option available, based on a set of stable preferences. However, what happens for hard decisions when the available options are preferred equally? We show that in such stalemate situations, decision-makers adjust their preferences dynamically during the process of decision-making, and these preference adjustments are predicted by a left prefrontal-parietal network. We also show that eye movements during decision-making are predictive of the magnitude of the upcoming value change. Our results suggest that preferences are dynamic, adjusted every time a hard decision is made, prompting a re-evaluation of existing frameworks of decision-making.

Induced Preference Improves Offspring Fitness in a Phytopathogen Vector.

In the Asian citrus psyllid (Diaphorina citri Kuwayama), learning facilitates host recognition and mate preference; however, it is unclear whether induced female oviposition preference occurs in this species. We investigated the influence of natal host experience on adult oviposition preference when reared on either 'Valencia' orange (Citrus x sinesis) or orange jasmine (Murraya paniculata). Psyllids reared on 'Valencia' orange preferred 'Valencia' orange as an oviposition host compared with orange jasmine, whereas there was no difference in oviposition between the two hosts in orange jasmine reared psyllids. Nymphs transferred from 'Valencia' orange to orange jasmine were smaller in adult size and required more time for development. These findings were reversed in orange jasmine reared psyllids, which increased in size and displayed shorter development times when transferred from orange jasmine to 'Valencia' orange. However, mortality increased in nymphs transferred to the non-natal host species in both treatment groups compared with nymphs transferred to the same host. These results indicate an association between host plant preference and performance in this species. Maternal host experience appeared to influence the oviposition preference in this species. Juvenile psyllid performance appeared negatively affected by orange jasmine plants such that fitness was reduced, suggesting benefits for maternal host fidelity in those insects not acclimated to feeding on orange jasmine. Induced oviposition preference may provide an important mechanism of adaptive plasticity in D. citri reproductive strategies, allowing females to discriminate among potential host species in favor of those to which her offspring are best adapted.

Social learning as a way to overcome choice-induced preferences? Insights from humans and rhesus macaques.

Much theoretical attention is currently devoted to social learning. Yet, empirical studies formally comparing its effectiveness relative to individual learning are rare. Here, we focus on free choice, which is at the heart of individual reward-based learning, but absent in social learning. Choosing among two equally valued options is known to create a preference for the selected option in both humans and monkeys. We thus surmised that social learning should be more helpful when choice-induced preferences retard individual learning than when they optimize it. To test this prediction, the same task requiring to find which among two items concealed a reward was applied to rhesus macaques and humans. The initial trial was individual or social, rewarded or unrewarded. Learning was assessed on the second trial. Choice-induced preference strongly affected individual learning. Monkeys and humans performed much more poorly after an initial negative choice than after an initial positive choice. Comparison with social learning verified our prediction. For negative outcome, social learning surpassed or at least equaled individual learning in all subjects. For positive outcome, the predicted superiority of individual learning did occur in a majority of subjects (5/6 monkeys and 6/12 humans). A minority kept learning better socially though, perhaps due to a more dominant/aggressive attitude toward peers. Poor learning from errors due to over-valuation of personal choices is among the decision-making biases shared by humans and animals. The present study suggests that choice-immune social learning may help curbing this potentially harmful tendency. Learning from successes is an easier path. The present data suggest that whether one tends to walk it alone or with a peer's help might depend on the social dynamics within the actor/observer dyad.

Selection of artificial hosts for oviposition by wild Anastrepha obliqua (Macquart) (Diptera, Tephritidae): influence of adult food and effect of experience / Seleção de hospedeiros artificiais para oviposição por Anastrepha obliqua (Macquart) (Diptera, Tephritidae) selvagem: influência do alimento do adulto e efeito da experiência

Several factors influence the selection of oviposition substrates by insects. The aim of the present work was to find answers to the following questions related to the oviposition behavior of Anastrepha obliqua. Can carbohydrates (glucose or sucrose) present in the adult diet have influence on the female preference for an oviposition substrate with similar composition? Can the previous experience with a host containing one of mentioned carbohydrates interfere in further selection of oviposition substrates? The results showed that the kind of carbohydrate present in the adult diet did not affect the female preference for an artificial oviposition substrate, neither when it was presented by itself nor in combination with brewer's yeast. The effect of experience in the oviposition behavior was observed when there was a previous contact with artificial oviposition substrates containing yeast and sucrose. The data are discussed in terms of the behavioral plasticity presented by this species in relation to feeding and oviposition behaviors.

Vários fatores podem atuar durante a seleção de substratos para oviposição por insetos. O presente estudo teve por objetivo responder às seguintes questões relacionadas ao comportamento de oviposição de Anastrepha obliqua. O carboidrato presente na dieta do adulto (glicose ou sacarose) pode influenciar a preferência da fêmea por um substrato para oviposição com composição semelhante? A experiência prévia com um hospedeiro que possui um dos dois carboidratos citados pode interferir em escolhas futuras entre substratos para oviposição? Os resultados indicaram que o tipo de carboidrato presente na dieta do adulto não exerceu influência sobre a preferência das fêmeas por um substrato artificial para oviposição, tanto quando em combinação com lêvedo de cerveja ou quando sozinho. O efeito da experiência no comportamento de oviposição foi notado quando o contato prévio foi com substratos artificiais para oviposição contendo lêvedo e sacarose. Os resultados são discutidos com base na plasticidade comportamental apresentada pela espécie com relação ao comportamento alimentar e de oviposição.