Available and unavailable decoys in capuchin monkeys (Sapajus spp.) decision-making.

Decision-making has been observed to be systematically affected by decoys, i.e., options that should be irrelevant, either because unavailable or because manifestly inferior to other alternatives, and yet shift preferences towards their target. Decoy effects have been extensively studied both in humans and in several other species; however, evidence in non-human primates remains scant and inconclusive. To address this gap, this study investigates how choices in capuchin monkeys (Sapajus spp.) are affected by different types of decoys: asymmetrically dominated decoys, i.e., available and unavailable options that are inferior to only one of the other alternatives, and phantom decoys, i.e., unavailable options that are superior to another available alternative. After controlling for the subjective strength of initial preferences and the distance of each decoy from its target in attribute space, results demonstrate a systematic shift in capuchins' preference towards the target of both asymmetrically dominated decoys (whether they are available or not) and phantom decoys, regardless of what options is being targeted by such decoys. This provides the most comprehensive evidence to date of decoy effects in non-human primates, with important theoretical and methodological implications for future comparative studies on context effects in decision-making.

Understanding responses of people with ASD in diverse reasoning tasks: A formal study.

Recent studies have shown that in some reasoning tasks people with Autism Spectrum Disorder perform better than typically developing people. This paper compares four such tasks, namely a syllogistic task, two decision-making tasks, and a task from the heuristics and biases literature, the aim being to identify common structure as well as differences. In the terminology of David Marr's three levels of cognitive systems, the tasks show commonalities on the computational level in terms of the effect of contextual stimuli, though an in-depth analysis of such contexts provides certain distinguishing features in the algorithmic level. We also make some general remarks on our approach, so as to set the stage for further studies in the area which could provide a better understanding of the reasoning process of ASD individuals.

Heterostructured Interface Enables Uniform Zinc Deposition for High-Performance Zinc-Ion Batteries.

Zinc metal has considerable potential as a high-energy anode material for aqueous batteries due to its high theoretical capacity and environmental friendliness. However, dendrite growth and parasitic reactions at the electrode/electrolyte interface remain two serious problems for the Zn metal anode. Here, the heterostructured interface of ZnO rod array and CuZn5 layer is fabricated on the Zn substrate (ZnCu@Zn) to address these two issues. The zincophilic CuZn5 layer with abundant nucleation sites ensures the initial uniform Zn nucleation process during cycling. Meanwhile, the ZnO rod array grown on the surface of the CuZn5 layer can guide the subsequent homogeneous Zn deposition via spatial confinement and electrostatic attraction effects, leading to the dendrite-free Zn electrodeposition process. Consequently, the derived ZnCu@Zn anode exhibits an ultra-long lifespan of up to 2500 h with symmetric cells at the current density and capacity of 0.5 mA cm-2 /0.5 mA h cm-2 . Besides, a remarkable cyclability (75% retention for 2500 cycles at 2 A g-1 ) is achieved in the ZnCu@Zn||MnO2 full cell with a capacity of 139.7 mA h g-1 . This heterostructured interface with specific functional layers provides a feasible strategy for the design of high-performance metal anodes.

Context-effect bias in capuchin monkeys (Sapajus spp.): exploring decoy influences in a value-based food choice task.

Decision making is known to be liable to several context effects. In particular, adding a seemingly irrelevant alternative (decoy) to a set of options can modify preferences: typically, by increasing choices towards whatever option clearly dominates the decoy (attraction effect), but occasionally also decreasing its appeal and generating a shift in the opposite direction (repulsion effect). Both types of decoy effects violate rational choice theory axioms and suggest dynamic processes of preference-formation, in which the value of each alternative is not determined a priori, but it is instead constructed by comparing options during the decision process. These effects are well documented, both in humans and in other species: e.g., amoebas, ants, honeybees, frogs, birds, cats, dogs. However, evidence of decoy effects in non-human primates remains surprisingly mixed. This study investigates decoy effects in capuchin monkeys (Sapajus spp.), manipulating time pressure across different conditions, to test whether such effects require time-consuming comparative processes among available alternatives. Whereas the time-dependent nature of decoy effects is a robust finding in the human literature, this is its first investigation in non-human animals. Our results show that capuchins exhibit an attraction effect with decoys targeting their preferred food, and that this effect disappears under time pressure; moreover, we observe preliminary evidence of a repulsion effect when decoys target instead the less-preferred food, possibly due to the larger distance between decoy and target in the attribute space. Taken together, these results provide valuable insight on the evolutionary roots of comparative decision making.

Effects of Long-Term Language Use Experience in Sentence Processing: Evidence from Korean.

Attraction effects arise when a comprehender erroneously retrieves a distractor instead of a target item during memory retrieval operations. In Korean, considerable processing difficulties occur in the agreement relation checking between a subject and an honorific-marked predicate when an intervening distractor carries a non-honorific feature. We investigate how attraction effects are managed during the processing of Korean subject-predicate honorific agreement by two Korean-speaking groups with different language use experience backgrounds: college students and airline workers. Results showed that both groups demonstrated stable knowledge of the honorific agreement in the acceptability judgment task. In the self-paced reading task, the airline group, who used honorifics extensively in their workplace, was less affected by the attraction effect than the student group. Our findings suggest that long-term language use experience can modulate how language users manage potential influence from attraction effects in real-time sentence processing.

Offering male endoscopists as decoy option to nudge disinclined women to have colorectal cancer screening.

Previous studies have shown that a large proportion of women invited for bowel cancer screening prefer endoscopists of the same gender. We tested whether women who are initially disinclined to undergo flexible sigmoidoscopy screening would be more willing to have the test with a female practitioner if they were also offered a decoy appointment with a male practitioner. We conducted two online experiments with women aged 35-54, living in England, who did not intend to undergo flexible sigmoidoscopy screening. In both experiments, women were randomised to two conditions: (1) control (appointment with a female endoscopist) and (2) decoy (two appointments to choose from, one with a male endoscopist and one with a female endoscopist). Experiment 1 (N = 302) verified the conditions for the decoy using a conventional intention scale, while experiment 2 (N = 300) tested how the presence of the decoy influences the likelihood of women choosing the appointment with the female practitioner in a discrete choice task. While experiment 1 showed that the presence of the decoy increased intentions to attend the appointment with the female practitioner (p = 0.02), experiment 2 confirmed that women were more likely to choose the appointment with the female endoscopist if they were also offered the decoy (p < 0.001). In both experiments, the presence of the decoy decreased perceived difficulty of the screening decision and cognitive effort required to make the decision. Offering disinclined women a male practitioner increased intention to have the test with an endoscopist of the same gender. This suggests that male screening practitioners can be used as decoy options to increase the likelihood that women choose female practitioners and facilitate the screening decision.

When the Good Looks Bad: An Experimental Exploration of the Repulsion Effect.

When people are choosing among different options, context seems to play a vital role. For instance, adding a third option can increase the probability of choosing a similar dominating option. This attraction effect is one of the most widely studied phenomena in decision-making research. Its prevalence, however, has been challenged recently by the tainting hypothesis, according to which the inferior option contaminates the attribute space in which it is located, leading to a repulsion effect. In an attempt to test the tainting hypothesis and explore the conditions under which dominated options make dominating options look bad, we conducted four preregistered perceptual decision-making studies with a total of 301 participants. We identified two factors influencing individuals' behavior: stimulus display and stimulus design. Our results contribute to a growing body of literature showing how presentation format influences behavior in preferential and perceptual decision-making tasks.

People With Autism Spectrum Conditions Make More Consistent Decisions.

People with autism spectrum conditions (ASC) show reduced sensitivity to contextual stimuli in many perceptual and cognitive tasks. We investigated whether this also applies to decision making by examining adult participants' choices between pairs of consumer products that were presented with a third, less desirable "decoy" option. Participants' preferences between the items in a given pair frequently switched when the third item in the set was changed, but this tendency was reduced among individuals with ASC, which indicated that their choices were more consistent and conventionally rational than those of control participants. A comparison of people who were drawn from the general population and who varied in their levels of autistic traits revealed a weaker version of the same effect. The reduced context sensitivity was not due to differences in noisy responding, and although the ASC group took longer to make their decisions, this did not account for the enhanced consistency of their choices. The results extend the characterization of autistic cognition as relatively context insensitive to a new domain, and have practical implications for socioeconomic behavior.

Not just for consumers: context effects are fundamental to decision making.

Context effects--preference changes that depend on the availability of other options--have attracted a great deal of attention among consumer researchers studying high-level decision tasks. In the experiments reported here, we showed that these effects also arise in simple perceptual-decision-making tasks. This finding casts doubt on explanations limited to consumer choice and high-level decisions, and it indicates that context effects may be amenable to a general explanation at the level of the basic decision process. We demonstrated for the first time that three important context effects from the preferential-choice literature--similarity, attraction, and compromise effects--all occurred within a single perceptual-decision task. Not only do our results challenge previous explanations for context effects proposed by consumer researchers, but they also challenge the choice rules assumed in theories of perceptual decision making.

A query theory account of the attraction effect.

We provide novel support for Query Theory, a reason-based decision framework, extending it to multialternative choices and applying it to the classic phenomenon known as the attraction effect. In Experiment 1 (N = 261), we generalised the two key metrics used in Query Theory from binary to multialternative choices and found that reasons supporting the target option were generated earlier and in greater quantity than those supporting the competitor, as predicted by the theory. In Experiment 2 (N = 703), we investigated the causal relationships between reasoning and choices by exogenously manipulating the order in which participants generated their reasons. As predicted, the size of the attraction effect was a function of this query order manipulation. We also introduced a bidirectional reason coding protocol to measure the valence of reasons, which confirmed support for Query Theory. We suggest the Query Theory framework can be useful for studying the high-level deliberation processes behind multialternative choices.

A robust Bayesian test for identifying context effects in multiattribute decision-making.

Research on multiattribute decision-making has repeatedly shown that people's preferences for options depend on the set of other options they are presented with, that is, the choice context. As a result, recent years have seen the development of a number of psychological theories explaining context effects. However, much less attention has been given to the statistical analyses of context effects. Traditionally, context effects are measured as a change in preference for a target option across two different choice sets (the so-called relative choice share of the target, or RST). We first show that the frequently used definition of the RST measure has some weaknesses and should be replaced by a more appropriate definition that we provide. We then show through a large-scale simulation that the RST measure as previously defined can lead to biased inferences. As an alternative, we suggest a Bayesian approach to estimating an accurate RST measure that is robust to various circumstances. We applied the two approaches to the data of five published studies (total participants, N = 738), some of which used the biased approach. Additionally, we introduce the absolute choice share of the target (or AST) as the appropriate measure for the attraction effect. Our approach is an example of evaluating and proposing proper statistical tests for axiomatic principles of decision-making. After applying the AST and the robust RST to published studies, we found qualitatively different results in at least one-fourth of the cases. These results highlight the importance of utilizing robust statistical tests as a foundation for the development of new psychological theories.

When alternative hypotheses shape your beliefs: Context effects in probability judgments.

When people are asked to estimate the probability of an event occurring, they sometimes make different subjective probability judgments for different descriptions of the same event. This implies the evidence or support recruited to make these judgments is based on the descriptions of the events (hypotheses) instead of the events themselves, as captured by Tversky and Koehler's (1994) support theory. Support theory, however, assumes each hypothesis elicits a fixed level of support (support invariance). Here, across three studies, we tested this support invariance assumption by asking participants to estimate the probability that an event would occur given a set of relevant statistics. We show that the support recruited about a target hypothesis can depend on the other hypotheses under consideration. Results reveal that for a pair of competing hypotheses, one hypothesis (the target hypothesis) appears more competitive relative to the other when a dud-a hypothesis dominated by the target hypothesis-is present. We also find that the target hypothesis can appear less competitive relative to the other when a resembler-a hypothesis that is similar to the target hypothesis-is present. These context effects invalidate the support invariance assumption in support theory and suggest that a similar process that drives preference construction may also underlie belief construction.

Fluorescent and visual sensing of sodium dodecylbenzene sulfonate with an aminosilane self-condensation promoting and electrostatic attraction effect-based ratiometric probe.

BACKGROUND: Increasing attention has been paid to sodium dodecylbenzene sulfonate (SDBS) detection because it could cause damage to human body and environmental water. For example, SDBS must not be detected on tableware surface according to national standard of China (GB 14934-2016). However, there is no report heretofore addressing SDBS sensing on surfaces. More importantly, the interferents often affect the sensing performance of analytical approaches. Hence, there is an urgent need to establish a method with good anti-interference ability for SDBS detection both on tableware surfaces and in water. RESULTS: Inspired by a finding that SDBS could cause the generation of white turbidity in (3-aminopropyl)trimethoxysilane (APTMS, an aminosilane) aqueous solution, APTMS modified Mn doped ZnS quantum dots (QDs) and fluorescent (FL) whitening agent (FWA) were constructed as a ratiometric probe for FL and visual sensing of SDBS. The modified QDs aggregated and settled in presence of SDBS, which was likely to be connected to the stimulatory effect of SDBS on the APTMS self-condensation and the electrostatic attraction. The FL emission from the QDs at 605 nm then decreased dramatically, whereas that at 425 nm was virtually constant owing to FWA. SDBS sensing could be achieved by calculating the ratio change of their FL intensities. The detection limits of FL and visual methods were found to be 0.011 and 10 µg/L, respectively, making it one of the most sensitive approaches in literature. Finally, it was successfully utilized for SDBS detection on tableware surfaces and in water. SIGNIFICANCE: Herein, the specific interaction between SDBS and APTMS was reported and the reaction mechanisms were explored for the first time. The proposed probe based on the effect described above provided a promising potential for SDBS analysis owing to high sensitivity, selectivity, anti-interference ability, and stability (in 20 days).

Emotional Attractors in Subject-Verb Number Agreement.

Considering the crosstalk between brain networks that contain linguistic and emotional information and that no studies have examined the impact of semantic information of affective nature on subject-verb number agreement, the present Event Related Potential (ERP) study investigated the extent to which emotional local nouns whose number mismatched that of subject head nouns might be considered by the parser during comprehension of grammatically correct sentences. To this end, twenty-eight Spanish native speakers were tested on a self-paced reading task while their brain activity was recorded. The experimental materials consisted of 120 sentences where the valence (negative vs. neutral) and number (singular vs. plural) of the local noun of the singular subject noun-phrase (NP) were manipulated; El gorro de aquel/aquellos cazador(es)/mecánico(s) era… [The hat of that/those hunter(s)/mechanic(s) was…]. ERP results measured in the local noun position showed that valence and number interacted in the 300-500 ms (negative component) and 780-880 ms (late positivity) time windows. In the (target) verb position, the two factors only interacted in the late 780-880 ms time window, revealing an "ungrammatical illusion" for plural marked neutral words. Our findings suggest that number agreement is sensitive to affective meaning but that the emotional information of an attractor is considered in different operations and at different stages during grammatical sentence processing; it can affect lexical and syntactic representation retrieval of a subject-NP and impact agreement encoding only at late stages of processing, during verb agreement and feature integration.

The repulsion effect in preferential choice and its relation to perceptual choice.

People rely on the choice context to guide their decisions, violating fundamental principles of rational choice theory and exhibiting phenomena called context effects. Recent research has uncovered that dominance relationships can both increase or decrease the choice share of the dominating option, marking the two ends of an attraction-repulsion continuum. However, empirical links between the two opposing effects are scarce and theoretical accounts are missing altogether. The present study (N = 55) used eye tracking alongside a within-subject design that contrasts a perceptual task and a preferential-choice analog in order to bridge this gap and uncover the underlying information-search processes. Although individuals differed in their perceptual and preferential choices, they generally engaged in alternative-wise comparisons and a repulsion effect was present in both conditions that became weaker the more predominant the attribute-wise comparisons were. Altogether, our study corroborates the notion that repulsion effects are a robust and general phenomenon that theoretical accounts need to take seriously.

The effect of ambient sounds on decision-making and heart rate variability in autism.

LAY ABSTRACT: Many autistic people report difficulties making decisions during everyday tasks, such as shopping. To examine the effect of sounds on decision-making, we developed a supermarket task where people watched a film shown from the shopper's perspective and were asked to make decisions between different products. The task was divided into three sections and participants completed each section in a different auditory environment: (1) no sounds, (2) non-social sounds (e.g. fridges humming) and (3) social sounds (e.g. people talking). Thirty-eight autistic and 37 neurotypical adults took part. We measured decision-making by examining how long it took to make a decision and how consistent people were with their decisions. We also measured heart rate variability because this biological response provides a measure of anxiety. After the supermarket shopping task, participants told us in their own words about their experiences. Autistic participants said that they found the non-social and social sound conditions more difficult than the no sound condition, and autistic participants found the social sound condition more negative than neurotypical participants. However, decision-making and heart rate variability were similar for autistic and neurotypical participants across the sound conditions, suggesting that these measures may not have been sensitive enough to reflect the experiences the autistic participants reported. Further research should consider alternative measures to explore the experiences reported by autistic people to help us understand which specific aspects of the environment autistic people are sensitive to. This, in turn, may enable more specific and evidence-based autism-friendly changes to be made.

Framing context effects with reference points.

Research on reference points highlights how alternatives outside the choice set can alter the perceived value of available alternatives, arguably framing the choice scenario. The present work utilizes reference points to study the effects of framing in preferential choice, using the similarity and attraction context effects as performance measures. We specifically test the predictions of Multialternative Decision by Sampling (MDbS; Noguchi & Stewart, 2018), a recent preferential choice model that can account for both reference points and context effects. In Experiment 1, consistent with predictions by MDbS, we find a standard similarity effect when no reference point is given that increases when both dimensions are framed negatively and decreases when both dimensions are framed positively. Contrary to predictions by MDbS, when the two dimensions are framed as tradeoffs, participants prefer whichever alternative performs best in the negatively framed dimension. Performance of MDbS was improved by the addition of a frame-based global attention allocation mechanism. Experiment 2 extends these results to a "by-dimension" presentation format in an attempt to bring participant behavior in line with MDbS assumptions. The empirical and modeling results replicated those of Experiment 1. Experiment 3 used the attraction effect to test the effects of framing when the best-performing alternative on each dimension was identical across target conditions, therefore reducing the potential effects of a global attention allocation mechanism. The effects of framing were indeed greatly reduced, and the performance of MDbS was markedly improved. The results extend framing to the context effects literature, provide new benchmarks for models and theories of context effects, and point to the need for a global attention mechanism.

Effects of psychological distance on attraction effect.

The present study demonstrated that psychological distance influences the attraction effect by changing the weights of the attributes of options. Construal level theory proposes that the weight of a superordinate attribute increases with psychological distance, whereas the weight of a subordinate attribute decreases with psychological distance. The present hypothesis proposed that an asymmetrical change of weights of attributes would influence the relationship between options, and, consequently, the attraction effect would vary. The present study comprised two studies. In study 1, participants made choices among three lotteries in near and distant future conditions. Study 2 asked the participants to choose among three events in similar and dissimilar other conditions. The results showed that the choice of the asymmetrically dominating option, which was superior in superordinate attributes, increased as the psychological distance increased, whereas the choice of the asymmetrically dominating option, which was superior in subordinate attributes, decreased or stayed static.

Decoy effects in intertemporal and probabilistic choices the role of time pressure, immediacy, and certainty.

A decoy is an irrelevant option that, when added to a binary choice, is not selected but nonetheless alters the subjects' preferences, systematically biasing towards its target. The decoy effect, also known as attraction effect, is considered an anomaly of rational decision-making, albeit its applicability to real-life choices outside of laboratory settings has been challenged. In particular, when decoys have been studied in choices between outcomes occurring at different points in time, i.e. intertemporal choices, or with different probabilities of realizing their utility, i.e. probabilistic choices, results were mixed: sometimes decoys are impactful, sometimes they are not, and they seem to be more effective in biasing towards, respectively, larger-and-later and larger-and-riskier outcomes, rather than towards sooner-and-smaller or sooner-and-safer rewards. We suggest that this puzzling set of results can be clarified by focusing on two important influencing factors: time pressure and immediacy/certainty. Moreover, we argue that decoy effects constitute an excellent testbed to assess similarities and differences between intertemporal choice and risky decision-making, which constitutes another open issue in the study of human choice. Two studies are presented to support these claims. In Study 1 (N = 92), we demonstrate that asymmetrically dominated decoys influence both intertemporal choice and risky decision-making only in the absence of time pressure, since otherwise the comparative process required for the decoy to have an impact cannot occur, consistently with predictions made by connectionist models of decision. In Study 2 (N = 53), we show that, when the smaller option is no longer presented as immediate/certain (but rather as sooner/safer), the impact of decoys becomes symmetrical - that is, they can prompt subjects to become either more future-oriented/risk-prone or more present-oriented/risk-averse. We conclude by discussing the implications of these findings for our understanding of the multifaceted role of time and chance in decision making.

Effortful Processing Reduces the Attraction Effect in Multi-Alternative Decision Making: An Electrophysiological Study Using a Task-Irrelevant Probe Technique.

The attraction effect in multi-alternative decision making reflects the context-dependent violation of axioms that are considered fundamental to rational choice. This effect is believed to depend on relatively effortless and intuitive processing (System 1) rather than on effortful and elaborative processing (System 2). To investigate the relationship between cognitive resources and the attraction effect in detail, we used a task-irrelevant probe technique, wherein task-irrelevant auditory probes were presented while participants viewed each alternative in a decision-making task, and measured the electroencephalographic responses to the probes. Thirty participants solved 48 hypothetical purchase problems with three alternatives that differed in terms of two attributes. We found that, in the second epoch of the experimental trials (possibly corresponding to the evaluation and comparison stage), the mean N1 amplitudes of the event-related potentials elicited by the auditory probes were significantly smaller when participants chose the competitor (i.e., trials in which no attraction effect occurred) than when participants chose the target (i.e., trials in which an attraction effect may have occurred). This result suggests that the allocation of more cognitive resources to the alternatives disrupts the attraction effect. This finding supports the assumption that intuitive comparisons among alternatives executed by System 1 are critical for the occurrence of the attraction effect.