Roberto Almeida

If there is a line between semantics and pragmatics, where is it drawn? In this essay I propose that appreciating a sentence is subject to two sets of processes: linguistic (viz., syntactic, semantic) driving the composition of shallow propositions, and unbounded pragmatic (viz., thinking). In section 1, I discuss some guiding assumptions on cognitive architecture, which constrain the nature of linguistic and cognitive representations and processes—and by implication, the conception of the semantics/pragmatics divide I have to offer. The phenomena I examine in section 2, relying on linguistic arguments and experimental evidence, suggest that for certain constructions there is an early “literal” process of interpretation followed by a period of uncertainty, indicating that the early linguistic computations produce a “shallow” semantic representation, not a fully enriched one. The cases I discuss, culminating in metaphors and so-called indeterminate sentences, challenge the prowess of linguistic computations for resolving—even suggesting—interpretations.

The hypothesis that a wild-type strain of Xylella fastidiosa would restore the ability of rpfF mutants blocked in diffusible signal factor production to be transmitted to new grape plants by the sharpshooter vector Graphocephala atropunctata was tested. While the rpfF mutant was very poorly transmitted by vectors irrespective of whether they had also fed on plants infected with the wild-type strain, wild-type strains were not efficiently transmitted if vectors had fed on plants infected with the rpfF mutant. About 100-fewer cells of a wild-type strain attached to wings of a vector when suspended in xylem sap from plants infected with an rpfF mutant than in sap from uninfected grapes. The frequency of transmission of cells suspended in sap from plants that were infected by the rpfF mutant was also reduced over threefold. Wild-type cells suspended in a culture supernatant of an rpfF mutant also exhibited 10-fold less adherence to wings than when suspended in uninoculated culture media. A factor released into the xylem by rpfF mutants, and to a lesser extent by the wild-type strain, thus inhibits their attachment to, and thus transmission by, sharpshooter vectors and may also enable them to move more readily through host plants. © 2014 The American Phytopathological Society.

What type of conceptual information about an object do we get at a brief glance? In two experiments, we investigated the nature of conceptual tokening—the moment at which conceptual information about an object is accessed. Using a masked picture-word congruency task with dichoptic presentations at “brief” (50−60 ms) and “long” (190−200 ms) durations, participants judged the relation between a picture (e.g., a banana) and a word representing one of four property types about the object: superordinate (fruit), basic level (banana), a high-salient (yellow), or low-salient feature (peel). In Experiment 1, stimuli were presented in black-and-white; in Experiment 2, they were presented in red and blue, with participants wearing red-blue anaglyph glasses. This manipulation allowed for the independent projection of stimuli to the left- and right-hemisphere visual areas, aiming to probe the early effects of these projections in conceptual tokening. Results showed that superordinate and basic-level properties elicited faster and more accurate responses than high- and low-salient features at both presentation times. This advantage persisted even when the objects were divided into categories (e.g., animals, vegetables, vehicles, tools), and when objects contained high-salient visual features. However, contrasts between categories show that animals, fruits, and vegetables tend to be categorized at the superordinate level, while vehicles tend to be categorized at the basic level. Also, for a restricted class of objects, high-salient features representing diagnostic color information (yellow for the picture of a banana) facilitated congruency judgments to the same extent as that of superordinate and basic-level labels. We suggest that early access to object concepts yields superordinate and basic-level information, with features only yielding effects at a later stage of processing, unless they represent diagnostic color information. We discuss these results advancing a unified theory of conceptual representation, integrating key postulates of atomism and feature-based theories.

Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial and afimbrial adhesins and three loci involved in regulatory systems. Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit, is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design. © 2014, American Society for Microbiology.

For naturally competent bacteria, spatially structured growth can provide an environment for enhanced horizontal gene transfer through transformation and recombination. DNA is often present in the extracellular environment, such as in the extracellular matrix of biofilms, and the lysis of a single cell can result in high local DNA concentrations. Xylella fastidiosa is a naturally competent plant pathogen that typically lives in a surface-attached state, yet previous work characterizing the competence of this organism was conducted with planktonic cells in liquid environments. Here, we show that transformation and recombination efficiencies are two to three orders of magnitude higher for cells grown on solid compared with liquid media, with maximum recombination efficiencies of about 10-3. Cells were highly competent throughout their exponential growth phase, with no significant change in recombination efficiencies until population growth rates began to slow. Mutations in type IV pili, competency-related, and cell-cell signalling genes significantly impacted the ability of X. fastidiosa to acquire and incorporate DNA. Because X. fastidiosa is highly competent when growing in a surface-attached state, as it does within its insect vectors and host plants, recombination of naturally transformed DNA could be a significant route by which horizontal gene transfer occurs in natural environments. © 2014 SGM.

Conventional metaphors such as early bird are interpreted rather fast and efficiently. This is so because they might be stored as lexicalized, non-compositional expressions. In a previous study, employing a maze task, we showed that, after reading metaphors (John is an early bird so he can …), participants took longer and were less accurate in selecting the appropriate word (attend) when it was paired with a literally-related distractor (fly) rather than an unrelated one (cry). This suggests that the literal meaning of conventional metaphors is awakened or made available immediately after their metaphorical interpretation. But does the literal meaning remain available further downstream during sentence comprehension? In two experiments also employing a maze task, we examined whether the awakening effect can be obtained when there is a medium (6 to 8 words) and a large (11 to 13 words) distance between the metaphor and lexical choice. Results indicated that the metaphor awakening effect persists but decreases as word distance increases. An analysis of our data based on a GPT model showed that our maze effects could not be attributed to target predictability. Overall, our results suggest that the literal meaning of a metaphor is accessed and remains available for about three seconds, fading as the sentence unfolds over time. The results support a model of metaphor comprehension that postulates the availability of both literal and metaphoric content in the course of sentence processing.

Experimental studies have suggested that variables such as aptness or conventionality are predictors of people’s preference for expressing a particular topic–vehicle pair as either a metaphor or a simile. In the present study, we investigated if such variables would also be predictive within a more naturalistic context, where other variables, such as the intention to include an explanation, may also influence people’s decision. Specifically, we investigated the production of metaphor and simile expressions on the Internet via the Google search engine and checked for accompanying explanations, as well as the properties they expressed, to examine whether ratings such as aptness, conventionality, as well as participants’ own stated preference or the intention to produce an explanation, would predict which topic–vehicle pairs appeared more often as metaphor. We found that participants’ stated preference predicted metaphor dominance on the Internet, and that apt topic–vehicles occurred more often as metaphors. The explanations collected, however, occurred 82% of the time after similes, and familiar expressions were the most explained. Finally, comparing the properties expressed in these explanations to normed property lists, we found that simile explanations typically expressed a novel conception of the topic–vehicle relationship. Therefore, we found that Internet posters use metaphors to convey an apt relationship, as found in previous laboratory studies, but prefer using a simile frame when they want to express a relationship that readers will find novel.

Studies have suggested that metaphors (Lawyers are sharks) and similes (Lawyers are like sharks) have distinct representations: metaphors engender more figurative and abstract properties, whereas similes engender more literal properties. We investigated to what extent access to such representations occurs automatically, during on-line reading. In particular, we examined whether similes convey a more literal meaning by following the metaphors and similes with explanations that expressed either a figurative (dangerous) or a literal property (fish) of the vehicle. In a self-paced reading with a moving window paradigm, we presented participants with negated simile and metaphor main clauses (Lawyers are not (like) sharks) followed by explanations that also negated either a figurative (because lawyers are not dangerous) or a literal property of the vehicle (because lawyers are not fish). We found that vehicles (sharks) in metaphors were read significantly faster than those in similes. In addition, explanations negating a figurative property were read faster after metaphors, whereas explanations negating a literal property were read faster after similes. These results support the hypothesis that metaphors and similes rely on different interpretive processes, suggesting that similes access literal representations while metaphor access figurative ones in real time.

What are the roles of semantic and pragmatic processes in the interpretation of sentences in context? And how do we attain such interpretations when sentences are deemed indeterminate? Consider a sentence such as “Lisa began the book” which does not overtly express the activity that Lisa began doing with the book. Although it is believed that individuals compute a specified event to enrich the sentential representation – yielding, e.g., “began [reading] the book” – there is no evidence that a default event meaning is attained. Moreover, if indeterminate sentences are enriched, it is not clear where the information required to generate enriched interpretations come from. Experiment 1 showed that, in isolation, there is no default interpretation for indeterminate sentences. The experiment also showed that biasing contexts constrain event interpretations and improve plausibility judgments, suggesting that event representations for indeterminate sentences are generated by context. In Experiment 2, participants heard biasing discourse contexts and later falsely recognized foil sentences containing the biased events (“Lisa began reading the book”) at the same proportion and with the same confidence as the original indeterminate sentence (“Lisa began the book”). We suggest that indeterminate sentences trigger event-enriching inferences but only in sufficiently constraining contexts. We also suggest that indeterminate sentences create two memory traces, one for the proposition consistent with the denotational, compositional meaning, and another for the proposition that is enriched pragmatically over time.

As Macnamara (1978) once asked, how can we talk about what we see? We report on a study manipulating realistic dynamic scenes and sentences aiming to understand the interaction between linguistic and visual representations in real-world situations. Specifically, we monitored participants’ eye movements as they watched video clips of everyday scenes while listening to sentences describing these scenes. We manipulated two main variables. The first was the semantic class of the verb in the sentence and the second was the action/motion of the agent in the unfolding event. The sentences employed two verb classes—causatives (e.g., break) and perception/psychological (e.g., notice)—which impose different constraints on the nouns that serve as their grammatical complements. The scenes depicted events in which agents either moved towards a target object (always the referent of the verb-complement noun), away from it, or remained neutral performing a given activity (such as cooking). Scenes and sentences were synchronized such that the verb onset corresponded to the first video frame of the agent motion towards or away from the object. Results show effects of agent motion but weak verb-semantic restrictions: causatives draw more attention to potential referents of their grammatical complements than perception verbs only when the agent moves towards the target object. Crucially, we found no anticipatory verb-driven eye movements toward the target object, contrary to studies using non-naturalistic and static scenes. We propose a model in which linguistic and visual computations in real-world situations occur largely independent of each other during the early moments of perceptual input, but rapidly interact at a central, conceptual system using a common, propositional code. Implications for language use in real world contexts are discussed.

Sentences such as "The author started the book" are indeterminate because they do not make explicit what the subject (the author) started doing with the object (the book). In principle, indeterminate sentences allow for an infinite number of interpretations. One theory, however, assumes that these sentences are resolved by semantic coercion, a linguistic process that forces the noun "book" to be interpreted as an activity (e.g., writing the book) or by a process that interpolates this activity information in the resulting enriched semantic composition. An alternative theory, pragmatic, assumes classical semantic composition, whereby meaning arises from the denotation of words and how they are combined syntactically, with enrichment obtained via pragmatic inferences beyond linguistic-semantic processes. Cognitive neuroscience studies investigating the neuroanatomical and functional correlates of indeterminate sentences have shown activations either at the ventromedial pre-frontal cortex or at the left inferior frontal gyrus. These studies have supported the semantic coercion theory assuming that one of these regions is where enriched semantic composition takes place. Employing fMRI, we found that indeterminate sentences activate bilaterally the superior temporal gyrus, the right inferior frontal gyrus, and the anterior cingulate cortex, more so than control sentences ("The author wrote the book"). Activation of indeterminate sentences exceeded that of anomalous sentences ("…drank the book") and engaged more left- and right-hemisphere areas than other sentence types. We suggest that the widespread activations for indeterminate sentences represent the deployment of pragmatic-inferential processes, which seek to enrich sentence content without necessarily resorting to semantic coercion.