Healthy individuals display a tendency to allocate attention unequally across space, and this bias has implications for how individuals interact with their environments. However, the origins of this phenomenon remain relatively poorly understood. The present research examined the joint and independent contributions of two fundamental motivational systems - behavioural approach and inhibition systems (BAS and BIS) - to lateral spatial bias in a locomotion task. Participants completed self-report measures of trait BAS and BIS, then repeatedly traversed a room, blindfolded, aiming for a straight line. We obtained locomotion data from motion tracking to capture variations in the walking trajectories. Overall, walking trajectories deviated to the left, and this tendency was more pronounced with increasing BIS scores. Meanwhile, BAS was associated with relative rightward tendencies when BIS was low, but not when BIS was high. These results demonstrate for the first time an association between BIS and lateral spatial bias independently of variations in BAS. The findings also contribute to clarify the circumstances in which BAS is associated with a rightward bias. We discuss the implications of these findings for the neurobiological underpinnings of BIS and for the literature on spatial bias.
Autism Spectrum Disorder (ASD) has an intriguing auditory processing profile. Individuals show enhanced pitch discrimination, yet often find seemingly innocuous sounds distressing. This study used two behavioural experiments to examine whether an increased capacity for processing sounds in ASD could underlie both the difficulties and enhanced abilities found in the auditory domain. Autistic and non-autistic young adults performed a set of auditory detection and identification tasks designed to tax processing capacity and establish the extent of perceptual capacity in each population. Tasks were constructed to highlight both the benefits and disadvantages of increased capacity. Autistic people were better at detecting additional unexpected and expected sounds (increased distraction and superior performance respectively). This suggests that they have increased auditory perceptual capacity relative to non-autistic people. This increased capacity may offer an explanation for the auditory superiorities seen in autism (e.g. heightened pitch detection). Somewhat counter-intuitively, this same ‘skill’ could result in the sensory overload that is often reported - which subsequently can interfere with social communication. Reframing autistic perceptual processing in terms of increased capacity, rather than a filtering deficit or inability to maintain focus, increases our understanding of this complex condition, and has important practical implications that could be used to develop intervention programs to minimise the distress that is often seen in response to sensory stimuli.
Android robots are entering human social life. However, human-robot interactions may be complicated by a hypothetical Uncanny Valley (UV) in which imperfect human-likeness provokes dislike. Previous investigations using unnaturally blended images reported inconsistent UV effects. We demonstrate an UV in subjects' explicit ratings of likability for a large, objectively chosen sample of 80 real-world robot faces and a complementary controlled set of edited faces. An “investment game” showed that the UV penetrated even more deeply to influence subjects' implicit decisions concerning robots' social trustworthiness, and that these fundamental social decisions depend on subtle cues of facial expression that are also used to judge humans. Preliminary evidence suggests category confusion may occur in the UV but does not mediate the likability effect. These findings suggest that while classic elements of human social psychology govern human-robot social interaction, robust UV effects pose a formidable android-specific problem.
A growing body of research has focused on so-called ‘utilitarian’ judgments in moral dilemmas in which participants have to choose whether to sacrifice one person in order to save the lives of a greater number. However, the relation between such ‘utilitarian’ judgments and genuine utilitarian impartial concern for the greater good remains unclear. Across four studies, we investigated the relationship between ‘utilitarian’ judgment in such sacrificial dilemmas and a range of traits, attitudes, judgments and behaviors that either reflect or reject an impartial concern for the greater good of all. In Study 1, we found that rates of ‘utilitarian’ judgment were associated with a broadly immoral outlook concerning clear ethical transgressions in a business context, as well as with sub-clinical psychopathy. In Study 2, we found that ‘utilitarian’ judgment was associated with greater endorsement of rational egoism, less donation of money to a charity, and less identification with the whole of humanity, a core feature of classical utilitarianism. In Studies 3 and 4, we found no association between ‘utilitarian’ judgments in sacrificial dilemmas and characteristic utilitarian judgments relating to assistance to distant people in need, self-sacrifice and impartiality, even when the utilitarian justification for these judgments was made explicit and unequivocal. This lack of association remained even when we controlled for the antisocial element in ‘utilitarian’ judgment. Taken together, these results suggest that there is very little relation between sacrificial judgments in the hypothetical dilemmas that dominate current research, and a genuine utilitarian approach to ethics.
Children are notoriously bad at delaying gratification to achieve later, greater rewards (e.g., Piaget, 1970)-and some are worse at waiting than others. Individual differences in the ability-to-wait have been attributed to self-control, in part because of evidence that long-delayers are more successful in later life (e.g., Shoda, Mischel, & Peake, 1990). Here we provide evidence that, in addition to self-control, children’s wait-times are modulated by an implicit, rational decision-making process that considers environmental reliability. We tested children (M=4;6, N=28) using a classic paradigm-the marshmallow task (Mischel, 1974)-in an environment demonstrated to be either unreliable or reliable. Children in the reliable condition waited significantly longer than those in the unreliable condition (p<0.0005), suggesting that children's wait-times reflected reasoned beliefs about whether waiting would ultimately pay off. Thus, wait-times on sustained delay-of-gratification tasks (e.g., the marshmallow task) may not only reflect differences in self-control abilities, but also beliefs about the stability of the world.
Facial expressions of emotion are thought to have evolved from the development of facial muscles used in sensory regulation and later adapted to express moral judgment. Negative moral judgment includes the expressions of anger, disgust and contempt. Here, we study the hypothesis that these facial expressions of negative moral judgment have further evolved into a facial expression of negation regularly used as a grammatical marker in human language. Specifically, we show that people from different cultures expressing negation use the same facial muscles as those employed to express negative moral judgment. We then show that this nonverbal signal is used as a co-articulator in speech and that, in American Sign Language, it has been grammaticalized as a non-manual marker. Furthermore, this facial expression of negation exhibits the theta oscillation (3-8Hz) universally seen in syllable and mouthing production in speech and signing. These results provide evidence for the hypothesis that some components of human language have evolved from facial expressions of emotion, and suggest an evolutionary route for the emergence of grammatical markers.
We elevate our constructions to a special status in our minds. This ‘IKEA’ effect leads us to believe that our creations are more valuable than items that are identical, but constructed by another. This series of studies utilises a developmental perspective to explore why this bias exists. Study 1 elucidates the ontogeny of the IKEA effect, demonstrating an emerging bias at age 5, corresponding with key developmental milestones in self-concept formation. Study 2 assesses the role of effort, revealing that the IKEA effect is not moderated by the amount of effort invested in the task in 5-to-6-year olds. Finally, Study 3 examines whether feelings of ownership moderate the IKEA effect, finding that ownership alone cannot explain why children value their creations more. Altogether, results from this study series are incompatible with existing theories of the IKEA bias. Instead, we propose a new framework to examine biases in decision making. Perhaps the IKEA effect reflects a link between our creations and our self-concept, emerging at age 5, leading us to value them more positively than others' creations.
To accurately localize our limbs and guide movements toward external objects, the brain must represent the body and its surrounding (peripersonal) visual space. Specific multisensory neurons encode peripersonal space in the monkey brain, and neurobehavioral studies have suggested the existence of a similar representation in humans. However, because peripersonal space lacks a distinct perceptual correlate, its involvement in spatial and bodily perception remains unclear. Here, we show that applying brushstrokes in mid-air at some distance above a rubber hand-without touching it-in synchrony with brushstrokes applied to a participant’s hidden real hand results in the illusory sensation of a “magnetic force” between the brush and the rubber hand, which strongly correlates with the perception of the rubber hand as one’s own. In eight experiments, we characterized this “magnetic touch illusion” by using quantitative subjective reports, motion tracking, and behavioral data consisting of pointing errors toward the rubber hand in an intermanual pointing task. We found that the illusion depends on visuo-tactile synchrony and exhibits similarities with the visuo-tactile receptive field properties of peripersonal space neurons, featuring a non-linear decay at 40cm that is independent of gaze direction and follows changes in the rubber hand position. Moreover, the “magnetic force” does not penetrate physical barriers, thus further linking this phenomenon to body-specific visuo-tactile integration processes. These findings provide strong support for the notion that multisensory integration within peripersonal space underlies bodily self-attribution. Furthermore, we propose that the magnetic touch illusion constitutes a perceptual correlate of visuo-tactile integration in peripersonal space.
A unified general theory of human concept learning based on the idea that humans detect invariance patterns in categorical stimuli as a necessary precursor to concept formation is proposed and tested. In GIST (generalized invariance structure theory) invariants are detected via a perturbation mechanism of dimension suppression referred to as dimensional binding. Structural information acquired by this process is stored as a compound memory trace termed an ideotype. Ideotypes inform the subsystems that are responsible for learnability judgments, rule formation, and other types of concept representations. We show that GIST is more general (e.g., it works on continuous, semi-continuous, and binary stimuli) and makes much more accurate predictions than the leading models of concept learning difficulty, such as those based on a complexity reduction principle (e.g., number of mental models, structural invariance, algebraic complexity, and minimal description length) and those based on selective attention and similarity (GCM, ALCOVE, and SUSTAIN). GIST unifies these two key aspects of concept learning and categorization. Empirical evidence from three experiments corroborates the predictions made by the theory and its core model which we propose as a candidate law of human conceptual behavior.
Unlike the phonological loop in spoken language monitoring, sign language users' own production provides mostly proprioceptive feedback and only minimal visual feedback. Here we investigate whether sign production influences sign comprehension by exploiting hand dominance in a picture-sign matching task performed by left-handed signers and right-handed signers. Should all signers perform better to right-handed input, this would suggest that a frequency effect in sign perception drives comprehension. However, if signers perform better to congruent-handed input, this would implicate the production system’s role in comprehension. We found evidence for both hypotheses, with variation dependent on sign type. All signers performed faster to right-handers for phonologically simple, one-handed signs. However, left-handed signers preferred congruent-handed input for phonologically complex, two-handed asymmetrical signs. These results are in line with a weak version of the motor theory of speech perception, where the motor system is only engaged when comprehending complex input.