Richard H. Yaxley

Language Comprehenders Mentally Represent the Shapes of Objects

We examined the prediction that people activate perceptual symbols during language comprehension. Subjects read sentences describing an animal or object in a certain location. The shape of the object or animal changed as a function of its location (e.g., eagle in the sky, eagle in a nest). However, this change was only implied by the sentences. After reading a sentence, subjects were presented with a line drawing of the object in question. They judged whether the object had been mentioned in the sentence (Experiment 1) or simply named the object (Experiment 2). In both cases, responses were faster when the pictured objects shape matched the shape implied by the sentence than when there was a mismatch. These results support the hypothesis that perceptual symbols are routinely activated in language comprehension.

Spatial iconicity affects semantic relatedness judgments.

Three experiments were conducted to examine whether spatial iconicity affects semantic-relatedness judgments. Subjects made speeded decisions with regard to whether members of a simultaneously presented word pair were semantically related. In Experiment 1, the words were presented one above the other. In the experimental pair, the words denoted parts of larger objects (e.g., ATTIC-BASEMENT). The words were either in an iconic relation with their referents (e.g., ATTIC presented above BASEMENT) or in a reverse-iconic relation (BASEMENT above ATTIC). The reverse-iconic condition yielded significantly slower semantic-relatedness judgments than did the iconic condition. Experiments 2 and 3 showed that this effect did not occur when the words were presented horizontally, thus ruling out that the iconicity effect is due to the order in which the words are read. Two alternative explanations for this finding are discussed.

Experiential simulations of negated text information

We investigated the question of whether comprehenders mentally simulate a described situation even when this situation is explicitly negated in the sentence. In two experiments, participants read negative sentences such as There was no eagle in the sky, and subsequently responded to pictures of mentioned entities in the context of a recognition task. Participants’ responses following negative sentences were faster when the depicted entity matched rather than mismatched the negated situation. These results suggest that comprehenders simulate the negated situation when processing a negated sentence. The results thereby provide further support for the experiential-simulations view of language comprehension.

Simulating visibility during language comprehension

In this study, participants performed a sentence-picture verification task in which they read sentences about an agent viewing an object (e.g., moose) through a differentially occlusive medium (e.g., clean vs. fogged goggles), and then verified whether a subsequently pictured object was mentioned in the previous sentence. Picture verification latencies were shorter when the resolution of the pictured object and the resolution implied by the sentence matched than when they did not. These results suggest that the degree of visibility implied in linguistic context can influence immediate object interpretation. These data suggest that readers mentally simulate the visibility of objects during language comprehension. Thus, the simulation of linguistic descriptions is not limited to the activation of intrinsic object properties (e.g., object shape), but also invokes the perceptibility of referential objects given implied environmental context.

Perception of Auditory Motion Affects Language Processing

Previous reports have demonstrated that the comprehension of sentences describing motion in a particular direction (toward, away, up, or down) is affected by concurrently viewing a stimulus that depicts motion in the same or opposite direction. We report 3 experiments that extend our understanding of the relation between perception and language processing in 2 ways. First, whereas most previous studies of the relation between perception and language processing have focused on visual perception, our data show that sentence processing can be affected by the concurrent processing of auditory stimuli. Second, it is shown that the relation between the processing of auditory stimuli and the processing of sentences depends on whether the sentences are presented in the auditory or visual modality.

The role of color diagnosticity in object recognition and representation

The role of color diagnosticity in object recognition and representation was assessed in three Experiments. In Experiment 1a, participants named pictured objects that were strongly associated with a particular color (e.g., pumpkin and orange). Stimuli were presented in a congruent color, incongruent color, or grayscale. Results indicated that congruent color facilitated naming time, incongruent color impeded naming time, and naming times for grayscale items were situated between the congruent and incongruent conditions. Experiment 1b replicated Experiment 1a using a verification task. Experiment 2 employed a picture rebus paradigm in which participants read sentences one word at a time that included pictures of color diagnostic objects (i.e., pictures were substituted for critical nouns). Results indicated that the “reading” times of these pictures mirrored the pattern found in Experiment 1. In Experiment 3, an attempt was made to override color diagnosticity using linguistic context (e.g., a pumpkin was described as painted green). Linguistic context did not override color diagnosticity. Collectively, the results demonstrate that color information is regularly utilized in object recognition and representation for highly color diagnostic items.

Neural mechanisms of risky decision-making and reward response in adolescent onset cannabis use disorder

BACKGROUND Neural mechanisms of decision-making and reward response in adolescent cannabis use disorder (CUD) are underexplored. METHODS Three groups of male adolescents were studied: CUD in full remission (n=15); controls with psychopathology without substance use disorder history (n=23); and healthy controls (n=18). We investigated neural processing of decision-making and reward under conditions of varying risk and uncertainty with the Decision-Reward Uncertainty Task while participants were scanned using functional magnetic resonance imaging. RESULTS Abstinent adolescents with CUD compared to controls with psychopathology showed hyperactivation in one cluster that spanned left superior parietal lobule/left lateral occipital cortex/precuneus while making risky decisions that involved uncertainty, and hypoactivation in left orbitofrontal cortex to rewarded outcomes compared to no-reward after making risky decisions. Post hoc region of interest analyses revealed that both control groups significantly differed from the CUD group (but not from each other) during both the decision-making and reward outcome phase of the Decision-Reward Uncertainty Task. In the CUD group, orbitofrontal activations to reward significantly and negatively correlated with total number of individual drug classes the CUD patients experimented with prior to treatment. CUD duration significantly and negatively correlated with orbitofrontal activations to no-reward. CONCLUSIONS The adolescent CUD group demonstrated distinctly different activation patterns during risky decision-making and reward processing (after risky decision-making) compared to both the controls with psychopathology and healthy control groups. These findings suggest that neural differences in risky decision-making and reward processes are present in adolescent addiction, persist after remission from first CUD treatment, and may contribute to vulnerability for adolescent addiction.

Attentional bias affects change detection

Thirty smokers and 30 nonsmokers participated in aflicker study in which the role of attentional bias in change detection was examined. The participants observed picture pairs of everyday objects flicker on a computer screen until they detected the one object that had changed. In half of the pictures, a smoking-related object (e.g., a lighter) was included among smoking-unrelated objects (e.g., a spoon). Half of the smokers and half of the nonsmokers were aware of the experiment’s focus, and the other half were not. The smokers exhibited shorter detection latencies than did the nonsmokers when a smoking object changed and longer detection latencies when a nonsmoking object changed while a smoking object was present, and they exhibited detection latencies similar to those of the nonsmokers when smoking objects were not present. Interestingly, the nonsmokers displayed the same attentional bias as the smokers when they were aware of the experiment’s smoking focus, but they did not display any attentional bias when they were unaware. Thus, these findings provide evidence for long-term context-independent, as well as for short-term context-dependent, attentional bias.

Behavioral risk elicits selective activation of the executive system in adolescents: Clinical implications

We investigated adolescent brain processing of decisions under conditions of varying risk, reward, and uncertainty. Adolescents (n = 31) preformed a Decision–Reward Uncertainty task that separates decision uncertainty into behavioral and reward risk, while they were scanned using functional magnetic resonance imaging. Behavioral risk trials involved uncertainty about which action to perform to earn a fixed monetary reward. In contrast, during reward risk the decision that might lead to a reward was known, but the likelihood of earning a reward was probabilistically determined. Behavioral risk trials evoked greater activation than the reward risk and no risk conditions in the anterior cingulate, medial frontal gyrus, bilateral frontal poles, bilateral inferior parietal lobe, precuneus, bilateral superior-middle frontal gyrus, inferior frontal gyrus, and insula. Our results were similar to those of young adults using the same task (Huettel, 2006) except that adolescents did not show significant activation in the posterior supramarginal gyrus during behavioral risk. During the behavioral risk condition regardless of reward outcome, overall mean frontal pole activity showed a positive correlation with age during the behavioral and reward risk conditions suggesting a developmental difference of this region of interest. Additionally, reward response to the Decision–Reward Uncertainty task in adolescents was similar to that seen in young adults (Huettel, 2006). Our data did not show a correlation between age and mean ventral striatum activity during the three conditions. While our results came from a healthy high functioning non-maltreated sample of adolescents, this method can be used to address types of risks and reward processing in children and adolescents with predisposing vulnerabilities and add to the paucity of imaging studies of risk and reward processing during adolescence.