A unified mechanism for innate and learned visual landmark guidance in the insect central complex

Insects can navigate efficiently in both novel and familiar environments, and this requires flexiblity in how they are guided by sensory cues. A prominent landmark, for example, can elicit strong innate behaviours (attraction or menotaxis) but can also be used, after learning, as a specific directional cue as part of a navigation memory. However, the mechanisms that allow both pathways to co-exist, interact or override each other are largely unknown. Here we propose a model for the behavioural integration of innate and learned guidance based on the neuroanatomy of the central complex (CX), adapted to control landmark guided behaviours. We consider a reward signal provided either by an innate attraction to landmarks or a long-term visual memory in the mushroom bodies (MB) that modulates the formation of a local vector memory in the CX. Using an operant strategy for a simulated agent exploring a simple world containing a single visual cue, we show how the generated short-term memory can support both innate and learned steering behaviour. In addition, we show how this architecture is consistent with the observed effects of unilateral MB lesions in ants that cause a reversion to innate behaviour. We suggest the formation of a directional memory in the CX can be interpreted as transforming rewarding (positive or negative) sensory signals into a mapping of the environment that describes the geometrical attractiveness (or repulsion). We discuss how this scheme might represent an ideal way to combine multisensory information gathered during the exploration of an environment and support optimal cue integration.

Theory of Motivated Cue-Integration and COVID-19: Between Interoception, Somatization, and Radicalization

The global dissemination of COVID-19 creates confusion and ambiguity in nearly every aspect of life, including fear of contagion, heightened awareness of the mortality of self and family members, lack of power, and distrust of experts and decision-makers. In this stressful situation, the question arises as to what mechanisms distinguish between adaptive and maladaptive self-regulation. The theory of Motivated Cue-Integration (MCI) is a novel theory of self-regulation that provides a new perspective on the effect of COVID-19 on self-regulation deficiency as an example of psychological distress. Inspired by predictive coding, social cognition, embodied cognition, and experiential approach, MCI suggests that self-regulation is based on interaction between (1) high-level values and goals, (2) low-level interoceptive and exteroceptive signals, and (3) trust in epistemic authority or a significant other. Motivated Cue-Integration posits that individuals create meaning by making moment-to-moment predictions that affect their interpretation of the experience of ambiguity influenced by their relationship with epistemic authority. According to MCI, deficiency in self-regulation during COVID-19 could result either from over-sensitivity or under-sensitivity to low-level interoceptive and exteroceptive cues; rigidity or ambiguity of high-level goals, poor integration between the two levels of processing as well as distrust in epistemic authority. According to MCI, variations of these deficiencies may occur in various clinical phenomena such as alexithymia and somatization, as well as in social phenomena such as goal radicalization. Based on this reasoning, MCI claims that the mentalization of the relationship between interoceptive cues, exteroceptive cues, goals, and psychological needs of the person, as well as the improvement of confidence in epistemic authority, can promote adaptive self-regulation. Psychological intervention can foster trust in epistemic authority, increase the mentalization of interoceptive and exteroceptive cues, and their association with adaptive goals. As such, the integration of these elements in a way that facilitates incentives pathways and insight fosters a more integrated subjective experience, higher clarity of emotion, and positive internal dialogue which promotes action tendency.

What happened? Reconstructing the past through vision and sound

We introduce a novel experimental paradigm for studying multi-modal integration in causal inference. Our experiments feature a physically realistic Plinko machine in which a ball is dropped through one of three holes and comes to rest at the bottom after colliding with a number of obstacles. We develop a hypothetical simulation model which postulates that people figure out what happened by integrating visual and auditory evidence through mental simulation. We test the model in a series of three experiments. In Experiment 1, participants only receive visual information and either predict where the ball will land, or infer in what hole it was dropped based on where it landed. In Experiment 2, participants receive both visual and auditory information - they hear what sounds the dropped ball makes. We find that participants are capable of integrating both sources of information, and that the sounds help them figure out what happened. In Experiment 3, we show strong cue integration: even when vision and sound are individually completely non-diagnostic, participants succeed by combining both sources of evidence.

The evolution of social learning as phenotypic cue integration

Most analyses of the origins of cultural evolution focus on when and where social learning prevails over individual learning, overlooking the fact that there are other developmental inputs that influence phenotypic fit to the selective environment. This raises the question of how the presence of other cue ‘channels’ affects the scope for social learning. Here, we present a model that considers the simultaneous evolution of (i) multiple forms of social learning (involving vertical or horizontal learning based on either prestige or conformity biases) within the broader context of other evolving inputs on phenotype determination, including (ii) heritable epigenetic factors, (iii) individual learning, (iv) environmental and cascading maternal effects, (v) conservative bet-hedging, and (vi) genetic cues. In fluctuating environments that are autocorrelated (and hence predictable), we find that social learning from members of the same generation (horizontal social learning) explains the large majority of phenotypic variation, whereas other cues are much less important. Moreover, social learning based on prestige biases typically prevails in positively autocorrelated environments, whereas conformity biases prevail in negatively autocorrelated environments. Only when environments are unpredictable or horizontal social learning is characterized by an intrinsically low information content, other cues such as conservative bet-hedging or vertical prestige biases prevail. This article is part of the theme issue ‘Foundations of cultural evolution’.

On the locus of individual differences in perceptual flexibility: ERP evidence for perceptual warping of speech sounds

Listeners vary in how they categorize speech sounds: some are more step-like, while others are more gradient. Recent work suggests that gradient listeners are more flexible in cue integration and recovery from misperceptions (Kapnoula et al., 2017, 2021). We investigated the source of these differences and asked how they cascade to lexical processing. Individual differences in speech categorization were assessed via a visual analogue scaling (VAS) task. Following Toscano et al. (2010), we used the N1 ERP component to track pre-categorical encoding of speech cues. Separate tasks were used to measure inhibitory control and lexical processes. The N1 linearly tracked the continuum, reflecting a fundamentally gradient speechperception; however, for step-like listeners this linearity was disrupted near the boundary. This suggests that, while all listeners are generally gradient, there are individual differences deriving from the idiosyncratic encoding of specific cues, and that cue-level gradiency cascadesthroughout the system.

Explicit and implicit depth-cue integration: evidence of systematic biases with real objects

In a previous series of experiments using virtual stimuli, we found evidence that 3D shape estimation agrees to a superadditivity rule of depth-cue combination. According to this rule, adding depth cues leads to greater perceived depth magnitudes and, in principle, to depth overestimation. The mechanism underlying the superadditivity effect can be fully accounted for by a normative theory of cue integration, through the adaptation of a model of cue integration termed the Intrinsic Constraint (IC) model. As for its nature, it remains unclear whether superadditivity is a byproduct of the artificial nature of virtual environments, causing explicit reasoning to infiltrate behavior and inflate the depth judgments when a scene is richer in depth cues, or the genuine output of the process of depth-cue integration. In the present study, we addressed this question by testing whether the IC model’s prediction of superadditivity generalizes beyond VR environments to real world situations. We asked participants to judge the perceived 3D shape of cardboard prisms through a matching task. To assay the potential influence of explicit control over those perceptual estimates, we also asked participants to reach and hold the same objects with their fingertips and we analyzed the in-flight grip size during the reaching. Using physical objects ensured that all visual information was fully consistent with the stimuli’s 3D structure without computer-generated artifacts. We designed a novel technique to carefully control binocular and monocular 3D cues independently from one another, allowing to add or remove depth information from the scene seamlessly. Even with real objects, participants exhibited a clear superadditivity effect in both explicit and implicit tasks. Furthermore, the magnitude of this effect was accurately predicted by the IC model. These results confirm that superadditivity is an inherent feature of depth estimation.

The myth of visual depth cues IV: Cue integration

“Visual depth cues” are conventionally invoked to explain the perception of a 3D world. They are also said to be “combined” or “integrated” for even greater effectiveness. The logical and empirical problems (Maniatis 2021a-c) that apply to the various depth cues individually and the depth cue concept generally apply to “cue integration” as well. Evidence in favor of the view is ad hoc, “models” fundamentally incomplete and contradictions never resolved.

Right parietotemporal activity predicts sense of agency under uncertain delays of sensory outcomes

According to the optimal cue integration theory, the formation of sense of agency relies on both predictive and postdictive agency cues and how they are weighted based on their availability and reliability. Using a novel paradigm, we show for the first time a possible existence of a prediction signal prior to voluntary movement, which appears when postdictive agency cues (i.e., the judgment of the time between voluntary movement and a subsequent flash) are not reliable.