The question shapes the answer: the neural correlates of task differences reveal dynamic semantic processing

Task effects in semantic processing were investigated by contrasting the neural activation associated with two semantic categorization tasks (SCT) using event-related fMRI. The two SCTs involved different decision categories: is it an animal? vs. is it a concrete thing? Participants completed both tasks and, across participants, the same core set of items were presented in both tasks. Results showed task differences in the neural activation associated with these items: in the animal SCT there was greater activation in a number of frontal and temporal regions, including left superior and middle temporal gyri, while in the concrete SCT there was greater activation in left medial frontal gyrus and bilaterally in the precentral gyri. These results are interpreted as evidence of top-down modulation of semantic processing; participants make adjustments to optimize performance in a given task and these adjustments have consequences for the activation observed.     

Semantic interference during object naming in agrammatic and logopenic primary progressive aphasia (PPA)

This study examined the time course of object naming in 21 individuals with primary progressive aphasia (PPA) (8 agrammatic (PPA-G); 13 logopenic (PPA-L)) and healthy age-matched speakers (n = 17) using a semantic interference paradigm with related and unrelated interfering stimuli presented at stimulus onset asynchronies (SOAs) of −1000, −500, −100 and 0 ms. Results showed semantic interference (SI) (i.e. significantly slower RTs in related compared to unrelated conditions) for all groups at −500, −100 and 0 ms, indicating timely spreading activation to semantic competitors. However, both PPA groups showed a greater magnitude of SI than normal across SOAs. The PPA-L group and six PPA-G participants also evinced SI at −1000 ms, suggesting an abnormal time course of semantic interference resolution, and concomitant left hemisphere cortical atrophy in brain regions associated with semantic processing. These subtle semantic mapping impairments in non-semantic variants of PPA may contribute to the anomia of these patients.     

How the brain responds to any: an MEG study

The word any may appear in some sentences, but not in others. For example, any is permitted in sentences that contain the word nobody, as in Nobody ate any fruit. However, in a minimally different context any seems strikingly anomalous: ^*Everybody ate any fruit. The aim of the present study was to investigate how the brain responds to the word any in such minimally different contexts - where it is permitted (licensed) and where it is not permitted (unlicensed). Brain responses were measured from adult readers using magnetoencephalography (MEG). The results showed significantly larger responses to permissible contexts in the left posterior temporal areas between 400-500 ms and 590-660 ms. These results clarify the anatomy and timing of brain processes that contribute to our judgment that a word such as any is or is not permitted in a given context.     

Look over there! Unilateral gaze increases geographical memory of the 50 United States

Based on their specialized processing abilities, the left and right hemispheres of the brain may not contribute equally to recall of general world knowledge. US college students recalled the verbal names and spatial locations of the 50 US states while sustaining leftward or rightward unilateral gaze, a procedure that selectively activates the contralateral hemisphere. Compared to a no-unilateral gaze control, right gaze/left hemisphere activation resulted in better recall, demonstrating left hemisphere superiority in recall of general world knowledge and offering equivocal support for the hemispheric encoding asymmetry model of memory. Unilateral gaze- regardless of direction- improved recall of spatial, but not verbal, information. Future research could investigate the conditions under which unilateral gaze increases recall. Sustained unilateral gaze can be used as a simple, inexpensive, means for testing theories of hemispheric specialization of cognitive functions. Results support an overall deficit in US geographical knowledge in undergraduate college students.     

Can clouds dance? Part 2: An ERP investigation of passive conceptual expansion

Conceptual expansion, one of the core operations in creative cognition, was investigated in the present ERP study. An experimental paradigm using novel metaphoric, nonsensical and literal phrases was employed where individual differences in conceptual knowledge organization were accounted for by using participants’ responses to categorize the stimuli to each condition. The categorization was determined by their judgment of the stimuli on the two defining criteria of creativity: unusualness and appropriateness. Phrases judged as unusual and appropriate were of special interest as they are novel and unfamiliar phrases thought to passively induce conceptual expansion. The results showed a graded N400 modulation for phrases judged to be unusual and inappropriate (nonsense) or unusual and appropriate (conceptual expansion, novel metaphorical) relative to usual and appropriate (literal) phrases. The N400 is interpreted as indexing greater effort to retrieve semantic information and integrate the novel concepts presented through the phrases. Analyses of the later time-window showed an ongoing negativity that was graded in the same manner as the N400. The findings attest to the usefulness of investigating creative cognition using event-related electrophysiology.     

Memory for emotional words: The role of semantic relatedness,encoding task and affective valence

Emotional stimuli have been repeatedly demonstrated to be better remembered than neutral ones. The aim of the present study was to test whether this advantage in memory is mainly produced by the affective content of the stimuli or it can be rather accounted for by factors such as semantic relatedness or type of encoding task. The valence of the stimuli (positive, negative and neutral words that could be either semantically related or unrelated) as well as the type of encoding task (focused on either familiarity or emotionality) was manipulated. The results revealed an advantage in memory for emotional words (either positive or negative) regardless of semantic relatedness. Importantly, this advantage was modulated by the encoding task, as it was reliable only in the task which focused on emotionality. These findings suggest that congruity with the dimension attended at encoding might contribute to the superiority in memory for emotional words, thus offering us a more complex picture of the underlying mechanisms behind the advantage for emotional information in memory.     

Guarding the perimeter: The outside-inside dichotomy in disgust and bodily experience

Blending phenomenological and evolutionary approaches, three studies explored the relationship between the body, the self, and disgust. Study 1 demonstrated that body parts that interface with the environment are sensed more than internal body parts, and are more intimately associated with the self. Studies 2 and 3, exploring the bodily distribution of disgust via organ transplantation scenarios, revealed that (a) transplantation of interface body parts is more disgusting than transplantation of internal parts; (b) others' interface parts elicit greater disgust than others' internal parts; and (c) individual differences in disgust sensitivity manifest primarily in reasoning about interface parts. The outer/inner dichotomy is a fundamental feature of the relationship between body and self, reflecting the adaptive utility of concentrating attention on the interface with the environment. Correspondingly, disgust, the emotion that protects the organism from contamination, is focused on the intersection between the body and the environment.     

An inkblot for sexual preference: A semantic variant of the Affect Misattribution Procedure

A newly developed Semantic Misattribution Procedure (SMP), a semantic variant of the Affect Misattribution Procedure (AMP), was used in three studies as an indirect measure of sexual interest. Using a known-group approach, homosexual men (Studies 1 and 2), heterosexual men (Studies 1 to 3) and heterosexual women (Study 3) were asked to guess the meaning of briefly presented Chinese ideographs as “sexual” or “not sexual”. The ideographs were preceded by briefly presented primes depicting male and female individuals of varying sexual maturity. As hypothesised, the frequency of “sexual” responses increased after priming with pictures of individuals of the preferred sex and increasing sexual maturation. The SMP showed satisfactory reliability and convergent validity as indicated by correlations with direct and two indirect measures of sexual interest. In two further studies, the hypothesised pattern was replicated whereas a standard AMP with the identical prime stimuli did not produce this result. The potential usefulness of semantic variants of the AMP is discussed.     

A familiar pattern? Semantic memory contributes to the enhancement of visuo-spatial memories

In this study we quantify for the first time electrophysiological components associated with incorporating long-term semantic knowledge with visuo-spatial information using two variants of a traditional matrix patterns task. Results indicated that the matrix task with greater semantic content was associated with enhanced accuracy and RTs in a change-detection paradigm; this was also associated with increased P300 and N400 components as well as a sustained negative slow wave (NSW). In contrast, processing of the low semantic stimuli was associated with an increased N200 and a reduction in the P300. These findings suggest that semantic content can aid in reducing early visual processing of information and subsequent memory load by unitizing complex patterns into familiar forms. The N400/NSW may be associated with the requirements for maintaining visuo-spatial information about semantic forms such as orientation and relative location. Evidence for individual differences in semantic elaboration strategies used by participants is also discussed.     

The effects of gender on the retrieval of episodic and semantic components of autobiographical memory

Despite consistent evidence that women exhibit greater episodic memory specificity than men, little attention has been paid to gender differences in the production of episodic details during autobiographical recall under conditions of high and low retrieval support. Similarly the role of gender on the production of semantic details used to support autobiographical memory recollections of specific events has been largely unexplored. In the present study an undergraduate sample of 50 men and 50 women were assessed using the Autobiographical Interview (Levine, Svoboda, Hay, Winocur, & Moscovitch, 2002). Women recalled more episodic information compared to men in the high retrieval support condition, whereas no gender differences were found in the low retrieval support condition. In addition, women produced more repetitions compared to men in the high retrieval support condition. No gender differences were found in the production of semantic details. These results are interpreted in terms of gender differences in encoding and reminiscence practices. This research adds to the literature on gender differences in memory recall and suggests that gender is an important variable in explaining individual differences in AM recall.