What bats have to say about speech and language

Understanding the biological foundations of language is vital to gaining insight into how the capacity for language may have evolved in humans. Animal models can be exploited to learn about the biological underpinnings of shared human traits, and although no other animals display speech or language, a range of behaviors found throughout the animal kingdom are relevant to speech and spoken language. To date, such investigations have been dominated by studies of our closest primate relatives searching for shared traits, or more distantly related species that are sophisticated vocal communicators, like songbirds. Herein I make the case for turning our attention to the Chiropterans, to shed new light on the biological encoding and evolution of human language-relevant traits. Bats employ complex vocalizations to facilitate navigation as well as social interactions, and are exquisitely tuned to acoustic information. Furthermore, bats display behaviors such as vocal learning and vocal turn-taking that are directly pertinent for human spoken language. Emerging technologies are now allowing the study of bat vocal communication, from the behavioral to the neurobiological and molecular level. Although it is clear that no single animal model can reflect the complexity of human language, by comparing such findings across diverse species we can identify the shared biological mechanisms likely to have influenced the evolution of human language.     

Fixation durations in scene viewing: Modeling the effects of local image features,oculomotor parameters,and task

Scene perception requires the orchestration of image- and task-related processes with oculomotor constraints. The present study was designed to investigate how these factors influence how long the eyes remain fixated on a given location. Linear mixed models (LMMs) were used to test whether local image statistics (including luminance, luminance contrast, edge density, visual clutter, and the number of homogeneous segments), calculated for 1° circular regions around fixation locations, modulate fixation durations, and how these effects depend on task-related control. Fixation durations and locations were recorded from 72 participants, each viewing 135 scenes under three different viewing instructions (memorization, preference judgment, and search). Along with the image-related predictors, the LMMs simultaneously considered a number of oculomotor and spatiotemporal covariates, including the amplitudes of the previous and next saccades, and viewing time. As a key finding, the local image features around the current fixation predicted this fixation’s duration. For instance, greater luminance was associated with shorter fixation durations. Such immediacy effects were found for all three viewing tasks. Moreover, in the memorization and preference tasks, some evidence for successor effects emerged, such that some image characteristics of the upcoming location influenced how long the eyes stayed at the current location. In contrast, in the search task, scene processing was not distributed across fixation durations within the visual span. The LMM-based framework of analysis, applied to the control of fixation durations in scenes, suggests important constraints for models of scene perception and search, and for visual attention in general.     

Spontaneous adaptation explains why people act faster when being imitated

The human ability to perform joint actions is often attributed to high-level cognitive processes. For example, the finding that action leaders act faster when imitated by their partners has been interpreted as evidence for anticipation of the other’s actions (Pfister, Dignath, Hommel, & Kunde, 2013). In two experiments, we showed that a low-level mechanism can account for this finding. Action leaders were faster when imitated than when counterimitated, but only if they could observe their partner’s actions (Exp. 1). Crucially, when due to our manipulation the partner’s imitative actions became slower than the counterimitative actions, leaders also became slower when they were imitated, and faster when counterimitated (Exp. 2). Our results suggest that spontaneous temporal adaptation is a key mechanism in joint action tasks. We argue for a reconsideration of other phenomena that have traditionally been attributed solely to high-level processes.     

Memory consolidation effects on memory stabilization and item integration in older adults

This study examined the differential effects of aging on consolidation processes that strengthen newly acquired memory traces in veridical form (memory stabilization) versus consolidation processes that are responsible for integrating these memory traces into an existing body of knowledge (item integration). Older adults learned 13 nonwords and were tested on their memory for the nonwords, and on whether these nonwords impacted upon processing of similar-sounding English words immediately and 24 hours later. Participants accurately recognized the nonwords immediately, but showed significant decreases in delayed recognition and recall. In comparison, the nonwords impacted upon processing of similar-sounding words only in the delayed test. Together, these findings suggest that memory consolidation processes may be more evident in item integration than memory stabilization processes for new declarative memories in older adults.     

The metaphor police: A case study of the role of metaphor in explanation

While many scholars have pointed to the role of metaphor in explanation, relatively little experimental research has examined whether and how metaphors are used and understood in everyday explanatory discourse. Across 3 experiments, we investigated the nature and function of metaphor in explanation by drawing on a real-world example where the terms guardian and warrior were used to metaphorically explain the role of police officers. We found, first, that the associations participants brought to mind for these concepts differed depending on whether they had previously answered questions about law enforcement (e.g., associations for warrior emphasized aggression and violence rather than strength and bravery when participants had previously answered questions about policing). Second, people were almost evenly split in their judgment of which metaphor was more appropriate to explain the role of law enforcement; this preference was highly predictive of beliefs related to policing and the criminal justice system. Third, and most important, using these metaphors to explain the job of policing causally influenced attitudes toward law enforcement in a metaphor-congruent manner (i.e., exposure to the guardian metaphor led to more positive attitudes), a finding that could not be accounted for by basic lexical priming. These studies complement existing work that has identified metaphor as a mechanism for representing abstract concepts, but also highlight the communicative and explanatory, rather than representational, functions of metaphor by showing that metaphors can encapsulate and convey an array of structured attitudes and beliefs.     

The explanatory structure of unexplainable events: Causal constraints on magical reasoning

A common intuition, often captured in fiction, is that some impossible events (e.g., levitating a stone) are “more impossible” than others (e.g., levitating a feather). We investigated the source of this intuition, hypothesizing that graded notions of impossibility arise from explanatory considerations logically precluded by the violation at hand but still taken into account. Studies 1–4 involved college undergraduates (n = 357), and Study 5 involved preschool-aged children (n = 32). In Studies 1 and 2, participants saw pairs of magical spells that violated one of 18 causal principles—six physical, six biological, and six psychological—and were asked to indicate which spell would be more difficult to learn. Both spells violated the same causal principle but differed in their relation to a subsidiary principle. Participants’ judgments of spell difficulty honored the subsidiary principle, even when participants were given the option of judging the two spells equally difficult. Study 3 replicated those effects with Likert-type ratings; Study 4 replicated them in an open-ended version of the task in which participants generated their own causal violations; and Study 5 replicated them with children. Taken together, these findings suggest that events that defy causal explanation are interpreted in terms of explanatory considerations that hold in the absence of such violations.     

The scope of formal explanation

The existence of multiple modes of explanation means that a crucial step in the process of generating explanations has to be selecting a particular mode. The present article identifies the key conceptual, as well as some pragmatic and epistemological, considerations that license the use of the formal mode of explanation, and thus that enter into the process of selecting and generating a formal explanation. Formal explanations explain the presence of certain properties in an instance of a kind by reference to the kind of thing it is (e.g. That has four legs because it is a dog). As such, this mode of explanation is intrinsically tied to kind representations and is applicable domain-generally. Although it is possible for formal explanation to apply domain-generally, for any given kind it is selective in its application, in that it can explain some, but not all, properties of the instances of a kind. It also appears that different types of properties can receive formal explanations across different domains. This article provides a sketch of a theory of the selectivity of formal explanation that results from the manner in which kinds of different types are distinguished. The present discussion also suggests how the mechanisms underlying formal explanations may contribute to the illusion of explanatory depth Keil (Trends in Cognitive Sciences, 7, 368–373,2003), the operation of the inherence heuristic Cimpian & Salomon (Behavioral and Brain Sciences, 37, 461–480, 2014a; Behavioral and Brain Sciences, 37, 506–527,2014b), and psychological essentialism (Gelman, 2003).     

Algebraic reasoning and bat-and-ball problem variants: Solving isomorphic algebra first facilitates problem solving later

The classic bat-and-ball problem is used widely to measure biased and correct reasoning in decision-making. University students overwhelmingly tend to provide the biased answer to this problem. To what extent might reasoners be led to modify their judgement, and, more specifically, is it possible to facilitate problem solution by prompting participants to consider the problem from an algebraic perspective? One hundred ninety-seven participants were recruited to investigate the effect of algebraic cueing as a debiasing strategy on variants of the bat-and-ball problem. Participants who were cued to consider the problem algebraically were significantly more likely to answer correctly relative to control participants. Most of this cueing effect was confined to a condition that required participants to solve isomorphic algebra equations corresponding to the structure of bat-and-ball question types. On a subsequent critical question with differing item and dollar amounts presented without a cue, participants were able to generalize the learned information to significantly reduce overall bias. Math anxiety was also found to be significantly related to bat-and-ball problem accuracy. These results suggest that, under specific conditions, algebraic reasoning is an effective debiasing strategy on bat-and-ball problem variants, and provide the first documented evidence for the influence of math anxiety on Cognitive Reflection Test performance.     

Improved low-cost,MR-compatible olfactometer to deliver tobacco smoke odor

We describe a low-cost, MRI-compatible olfactometer that delivers fresh cigarette smoke odor, a challenging odorant to present, as well as other odorants. This new olfactometer retains all of the advantages of an earlier design that was capable of only delivering volatile odors (Lowen & Lukas, Behavior Research Methods, 38, 307–313, 2006). The new system incorporates a novel switching mechanism that allows it to deliver fresh smoke generated from a burning cigarette during a stimulus presentation paradigm that might be employed in a cue-reactivity experiment. An evaluation study established that the olfactometer reliably delivered smoke to the participants and that tobacco smoke was discriminated from other odorants; there were no adverse reactions to the device.