Cognitive consequences of individual differences in arousal asymmetry

Prior research has demonstrated that semantic organization in the right hemisphere (RH) is more diffuse and specialized for distant semantic associates than is semantic organization in the left hemisphere (LH). The present research explored individual differences in this regard. If the RH is more specialized for distant semantic associates, then individuals with a more active RH should display greater activation of distant semantic associations. Two experiments were conducted to examine this issue. In both studies a line bisection task was used to assess arousal asymmetry. In Experiment 1, greater RH activation was associated with the ability to generate remote associates to three word stimuli. In Experiment 2, relatively greater RH activation was associated with enhanced priming of distant semantic associates. Taken together, these experiments demonstrate that arousal asymmetry is an individual difference variable that is related to variability in semantic organization and retrieval.     

Episodic future thinking in children compared to adolescents

Episodic thinking involves the ability to re-create past and to construct future personal events, which contain event-specific (episodic) and general (semantic) details. The richness of episodic thought for past events improves as children move into adolescence. The current study aims to examine changes in episodic future thinking and to establish the cognitive underpinning of these changes. Typically developing children (n = 14) and adolescents (n = 15) were tested using an adapted version of the Child Autobiographical Interview (CAI) that required generation of past and future personally relevant events. Relational memory and executive skills were also examined. Significant developmental gains were found in richness of events recall across temporal directions (past and future) and across different types of details (episodic and semantic). Developmental gains in richness of past events were also shown to correspond to developmental gains in generation of future events. Moreover, developmental changes in relational memory and (to a lesser extent) executive functions were found to relate to increases in the amount of episodic (but not semantic) details provided. Our study highlighted the similarities between past and future episodic thinking in typically developing children and adolescents. It also raises a possibility that children with developmental and neurological disorders with impaired relational memory and/or executive skills may be at risk of difficulties with episodic thinking.     

How semantic category modulates preschool children’s visual memory

The dynamic interplay between perception and memory has been explored in preschool children by presenting filtered stimuli regarding animals and artifacts. The identification of filtered images was markedly influenced by both prior exposure and the semantic nature of the stimuli. The identification of animals required less physical information than artifacts did. Our results corroborate the notion that the human attention system evolves to reliably develop definite category-specific selection criteria by which living entities are monitored in different ways.     

Lexical coherence in short-term memory: Strategic reconstruction or “semantic glue”?

This study explores the foundation of lexical/semantic phoneme binding effects in verbal short-term memory (STM). The immediate serial recall of pure lists of words and nonwords was compared with the recall of mixed lists that had either a predictable, alternating structure (e.g., wnwnwn) or an unpredictable structure (i.e., the serial positions of the words/nonwords could not be known in advance). The study provides evidence for two separate mechanisms by which long-term linguistic knowledge contributes to STM. First, there was evidence for automatic lexical/semantic binding effects that were independent of knowledge of lexical status. The nonwords in both types of mixed list damaged word recall and encouraged the phonological elements of words to migrate. In both alternating and unpredictable mixed lists, the phonemes of words were more likely than the phonemes of nonwords to be recalled together as a coherent item, suggesting that lexical/semantic knowledge encourages the phonological elements of words to emerge together in immediate serial recall, even when lexical status is unknown. Secondly, there was evidence for “strategic redintegration”, which was dependent on prior knowledge of the lexical status of the items in mixed lists. When participants recalled items that they knew to be words in advance, they were able to use this knowledge to constrain their responses so that they were more likely to be lexically appropriate. These findings motivate modifications to current theories of the interaction between linguistic knowledge and verbal short-term memory.     

The role of meaning in contextual cueing: Evidence from chess expertise

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context–target associations.     

Motor simulation in verbal knowledge acquisition

Recent research highlights the importance of motor processes for a wide range of cognitive functions such as object perception and language comprehension. It is unclear, however, whether the involvement of the motor system goes beyond the processing of information that is gathered through active action experiences and affects also the representation of knowledge acquired through verbal learning. We tested this prediction by varying the presence of motor interference (i.e., squeezing a ball vs. oddball detection task) while participants verbally acquired functional object knowledge and examined the effects on a subsequent object detection task. Results revealed that learning of functional object knowledge was only impaired when participants performed an effector-specific motor task while training. The present finding of an effector-specific motor interference effect on object learning demonstrates the crucial role of the motor system in the acquisition of novel object knowledge and provides support for an embodied account to perception and cognition.     

Naming digits in a semantic blocking paradigm

It is widely agreed that word numerals are processed similar to other words, and, thus, they can be named without semantic mediation. However, there is no consensus about Arabic digits. Although digits seem to have a preferential link to magnitude representation, there is some evidence indicating a possible asemantic route to access phonological information. In the present study, we used a semantic blocking paradigm to explore this question. In Experiment 1, participants were asked to name digits and pictures or numeral words and name of objects in a semantic blocked context and in a mixed context. For both types of numerical notation we found facilitation in the blocked condition relative to the mixed condition. In Experiment 2, participants named two-digit numbers in a blocked condition (short numerical distance) or in a mixed condition (large numerical distance). Again, facilitation was found for the blocked condition relative to the mixed condition. This pattern of results seems to indicate that Arabic digits, like number words, might be named through an asemantic route.     

My word! Interference from reading object names implies a role for competition during picture name retrieval

A related word prime has been found to interfere with picture naming after unrelated intervening trials (word-to-picture interference). Recently, Stroop-type picture–word interference effects have been interpreted in terms of a postlexical response exclusion process rather than a competitive lexical selection process. An experiment is reported that examines whether word-to-picture effects could reflect response exclusion mechanisms and, more generally, strategic processing of the word prime. Forty-eight volunteer university students named aloud sequences of semantically related (and unrelated) word primes and picture targets, separated by two unrelated filler stimuli. On half of the trials, participants were asked to count backwards in threes from a random number presented immediately after naming the prime word. They were also given a surprise recall test at the end of the naming block. Results for naming times and errors indicated a main effect of relatedness; semantic interference effects were not dependent on the unfilled gap following the word prime trial and were also not tied to episodic recall of prime words. The data indicate that slowed picture naming times are more likely to emerge from processes intrinsic to word prime naming rather than controlled processing and do not readily fit the postlexical response exclusion account. The results are considered in relation to two recent accounts of interference over unrelated trials, which refer to some form of competition at, or prior to, lexical access.     

Imageability,age of acquisition,and frequency factors in acronym comprehension

In spite of their unusual orthographic and phonological form, acronyms (e.g., BBC, HIV, NATO) can become familiar to the reader, and their meaning can be accessed well enough that they are understood. The factors in semantic access for acronym stimuli were assessed using a word association task. Two analyses examined the time taken to generate a word association response to acronym cues. Responses were recorded more quickly to cues that elicited a large proportion of semantic responses, and those that were high in associative strength. Participants were shown to be faster to respond to cues which were imageable or early acquired. Frequency was not a significant predictor of word association responses. Implications for theories of lexical organisation are discussed.