Body dysmorphic symptoms: phenomenology and ethnicity

Differences in the presentation of clinical features of body dysmorphic disorder (BDD) across ethnic groups have received little investigation. The current study assessed BDD symptoms in an ethnically diverse sample of adults (n=401) using an online survey. Participants completed self-report measures assessing BDD symptoms, body parts of concern and BDD behaviors. Compared to Caucasian participants, no significant differences were found in body parts or behaviors reported by Latino or African American participants. Significant group differences did emerge between Asian and Caucasian participants. Specifically, Asians reported more concern with straight hair and dark skin and fewer body shape concerns than Caucasians. Asians also endorsed lower rates of grooming, touching body parts, and camouflaging and higher rates of exercise compared to Caucasians. Although most clinical features of BDD appear similar across ethnic groups, results showed some differences in body parts and behaviors between Caucasians and Asian Americans with BDD symptoms.     

The influence of expertise and of physical complexity on visual short-term memory consolidation

We investigated whether the expertise of a perceiver and the physical complexity of a stimulus influence consolidation of visual short-term memory (VSTM) in a S1-S2 (Stimulus 1-Stimulus 2) change detection task. Consolidation is assumed to make transient perceptual representations in VSTM more durable, and it is investigated by postexposure of a mask shortly after offset of the perceived stimulus (S1; 17 to 483?ms). We presented colours, Chinese characters, pseudocharacters, and novel symbols to novices (Germans) or experts of Chinese language (Chinese readers). Physical complexity was manipulated by the number of strokes. Unfamiliar material was remembered worse than familiar material (Experiments 1, 2, and 3). For novices the absolute VSTM performance was better for physically simple than for complex material, whereas for experts the complexity did not matter-Chinese readers memorized Chinese characters (Experiment 3). Articulatory suppression did not change these effects (Experiment 2). We always observed a strong effect of SOA, but this effect was influenced neither by physical complexity nor by expertise; only the length of the interstimulus interval between S1 and the mask was relevant. This was observed even with short stimulus onset asynchrony (SOA) of 100?ms (Experiment 2) and in comparing colours and characters (Experiment 5). However, masks impaired memory if they were presented at the locations of the to-be-memorized items, but not beside them-that is, interference was location-based (Experiment 6). We explain the effect of SOA by the assumption that it takes time to stop encoding of information presented at item locations with the offset of S1. The increasing resistance against interference by irrelevant material appears as consolidation of S1.     

On the timescale of stimulus-based action-effect learning

When performing an action, people pick up associations between their actions and the resulting consequences of that action, a phenomenon that has been termed response (R)-effect (E) learning. In the present study, we investigated incidental R-E learning in a forced-choice-that is, a stimulus (S)-based-acquisition mode. Specifically, the study examined at which timescale R-E learning evolves-that is, how many encounters are actually needed to form stable R-E associations. The learning of R-E associations was assessed in a subsequent test phase via effect-based response priming. Experiment 1 tested 4 different numbers of S-R-E repetitions for a 2-2-2 S-R-E mapping. Experiment 2 disentangled the contributions of S-E and R-E associations to the facilitating impact of effect-based response priming by means of a 4-2-4 S-R-E mapping. Experiment 3 investigated whether R-E associations can be picked up even when a given E cannot be unequivocally predicted based on the antecedent S in case of inconsistent S-R-E couplings. Together, the results of the present study clearly show that R-E learning occurs in a stimulus-based action mode and that it evolves very rapidly after only 12 S-R-E repetitions. Moreover, the present findings suggest that at least in this initial phase of learning, complete S-R-E consistency seems to be relevant for R-E learning.     

On the theoretical error bound for estimating psychometric functions

The theoretical limits to the amount of error, or the Cramer-Rao bounds, were derived for estimating psychometric functions. These theoretical error bounds were compared with the variability of psychometric functions estimated from human as well as computer-simulated observers. For the simulated observers, due to the limited efficiency of the sampling strategies, including the placement of the signals and the distribution of the trials, the variances of the estimated parameters are seven times the theoretical bound for threshold and 22 times that for slope. For the human observers, the variance is 18 times the theoretical bounds for threshold and 80 times that for slope. Therefore, a major portion of the variances (60% for threshold and 73% for slope) for the human observers is associated with factors other than sampling strategies. Further improvement of the accuracy for estimating psychometric functions will depend on not only optimizing the sampling strategy, but also better understanding the various sources of error related to the behavior of human observers.     

Constraints on the processes responsible for the extrinsic normalization of vowels

Listeners tune in to talkers’ vowels through extrinsic normalization. We asked here whether this process could be based on compensation for the long-term average spectrum (LTAS) of preceding sounds and whether the mechanisms responsible for normalization are indifferent to the nature of those sounds. If so, normalization should apply to nonspeech stimuli. Previous findings were replicated with first-formant (F1) manipulations of speech. Targets on a [pt]–[p?t] (low–high F1) continuum were labeled as [pt] more after high-F1 than after low-F1 precursors. Spectrally rotated nonspeech versions of these materials produced similar normalization. None occurred, however, with nonspeech stimuli that were less speechlike, even though precursor–target LTAS relations were equivalent to those used earlier. Additional experiments investigated the roles of pitch movement, amplitude variation, formant location, and the stimuli's perceived similarity to speech. It appears that normalization is not restricted to speech but that the nature of the preceding sounds does matter. Extrinsic normalization of vowels is due, at least in part, to an auditory process that may require familiarity with the spectrotemporal characteristics of speech.     

A search asymmetry for interocular conflict

When two different images are presented to the two eyes, the percept will alternate between the images (a phenomenon called binocular rivalry). In the present study, we investigate the degree to which such interocular conflict is conspicuous. By using a visual search task, we show that search for interocular conflict is near efficient (15 ms/item) and can lead to a search asymmetry, depending on the contrast in the display. We reconcile our findings with those of Wolfe and Franzel (1988), who reported inefficient search for interocular conflict (26 ms/item) and found no evidence for a search asymmetry. In addition, we provide evidence for the suggestion that differences in search for interocular conflict are contingent on the degree of abnormal fusion of the dissimilar images.     

Attentional load inhibits vection

In this study, we examined the effects of cognitive task performance on the induction of vection. We hypothesized that, if vection requires attentional resources, performing cognitive tasks requiring attention should inhibit or weaken it. Experiment 1 tested the effects on vection of simultaneously performing a rapid serial visual presentation (RSVP) task. The results revealed that the RSVP task affected the subjective strength of vection. Experiment 2 tested the effects of a multiple-object-tracking (MOT) task on vection. Simultaneous performance of the MOT task decreased the duration and subjective strength of vection. Taken together, these findings suggest that vection induction requires attentional resources.     

An examination of the relation between traumatic event exposure and panic-relevant biological challenge responding among adolescents

The current study uniquely extended research that has linked traumatic event exposure to panic-spectrum problems among adolescents. It was hypothesized that among 127 adolescents (age range: 10 to 17 years; M = 14.63, SD = 2.24), those who endorsed a history of traumatic event exposure would evidence significantly greater anxious and fearful reactivity to a well-established 3-min voluntary hyperventilation procedure compared to nonexposed individuals. Results were consistent with hypotheses, suggesting traumatic event exposure is associated with anxious and fearful reactivity to abrupt increases in bodily arousal among adolescents. Moreover, consistent with hypotheses, anxiety sensitivity significantly mediated the relations between traumatic event exposure and both self-reported panic symptoms and panic symptoms elicited by the challenge. Future prospective research is now needed to better understand temporal relations between traumatic event exposure and indices of panic and related vulnerability.     

The time course of anticipatory constraint integration

Several studies have demonstrated that as listeners hear sentences describing events in a scene, their eye movements anticipate upcoming linguistic items predicted by the unfolding relationship between scene and sentence. While this may reflect active prediction based on structural or contextual expectations, the influence of local thematic priming between words has not been fully examined. In Experiment 1, we presented verbs (e.g., arrest) in active (Subject–Verb–Object) sentences with displays containing verb-related patients (e.g., crook) and agents (e.g., policeman). We examined patient and agent fixations following the verb, after the agent role had been filled by another entity, but prior to bottom-up specification of the object. Participants were nearly as likely to fixate agents “anticipatorily” as patients, even though the agent role was already filled. However, the patient advantage suggested simultaneous influences of both local priming and active prediction. In Experiment 2, using passive sentences (Object–Verb–Subject), we found stronger, but still graded influences of role prediction when more time elapsed between verb and target, and more syntactic cues were available. We interpret anticipatory fixations as emerging from constraint-based processes that involve both non-predictive thematic priming and active prediction.