Graphical representation fosters discovery in the 2–4–6 task

Compulsion and impulsivity are both primary features of drug addiction. Based on decades of animal research, we have a detailed understanding of the factors (both environmental and physiological) that influence compulsive drug use, but still know relatively little about the impulsive aspects of drug addiction. This review outlines our current knowledge of the relationship between impulsivity and drug addiction, focusing on cognitive and motor impulsivity, which are particularly relevant to this disorder. Topics to be discussed include the influence of chronic drug administration on impulsivity, the mechanisms that may explain drug-induced impulsivity, and the role of individual differences in the development of impulsive drug use. In addition, the manner in which contemporary theories of drug addiction conceptualize the relationship between impulsivity and compulsion is examined. Most importantly, this review emphasizes a critical role for animal research in understanding the role of impulsivity in the development and maintenance of drug addiction.     

Segregated in perception,integrated for action: Immunity of rhythmic sensorimotor coordination to auditory stream segregation

Auditory stream segregation can occur when tones of different pitch (A, B) are repeated cyclically: The larger the pitch separation and the faster the tempo, the more likely perception of two separate streams is to occur. The present study assessed stream segregation in perceptual and sensorimotor tasks, using identical ABBABB … sequences. The perceptual task required detection of single phase-shifted A tones; this was expected to be facilitated by the presence of B tones unless segregation occurred. The sensorimotor task required tapping in synchrony with the A tones; here the phase correction response (PCR) to shifted A tones was expected to be inhibited by B tones unless segregation occurred. Two sequence tempi and three pitch separations (2, 10, and 48 semitones) were used with musically trained participants. Facilitation of perception occurred only at the smallest pitch separation, whereas the PCR was reduced equally at all separations. These results indicate that auditory action control is immune to perceptual stream segregation, at least in musicians. This may help musicians coordinate with diverse instruments in ensemble playing.     

Edge-induced illusory contours and visual detection: Subthreshold summation or spatial cueing?

Findings that illusory contours can facilitate visual detection of a subthreshold real line (Dresp & Bonnet, 1995) were not replicated, when line-induced instead of edge-induced illusory contour stimuli were used (Salvano-Pardieu et al., 2006). Rather, the results of the latter study supported the importance of spatial cues. The present study was designed to investigate whether spatial cueing might also facilitate detection of targets superimposed on edge-induced illusory contours. In Experiment 1, a target line was superimposed on the illusory contour of a Kanizsa square, presented between dots with a precise or distant location to the target, or on a homogeneous field (control). Detection of the target was poorest for the control, followed by the distant-dots and Kanizsa conditions, whereas it was best for precisely cueing dots. Experiment 2 replicated the conditions in Experiment 1 (Kanizsa, precisely cueing dots, and control) with additional controls for possible luminance effects. The two new conditions matched the Kanizsa condition for overall luminance and preciseness of spatial cueing without generating illusory contours. Performance was best in the dot condition and worst in the control, but the same across the Kanizsa and matched luminance conditions. In Experiments 3 and 4, the stimuli presented were matched more closely to those used by Dresp and Bonnet, but still the results confirmed those obtained in our Experiments 1 and 2. Together, these experiments strongly suggest that detection is also facilitated by spatial cueing rather than subthreshold summation, in the case of edge-induced illusory contours.     

Flexibility of working memory encoding in a sentence–picture–sound verification task

Dual-process accounts of working memory have suggested distinct encoding processes for verbal and visual information in working memory, but encoding for nonspeech sounds (e.g., tones) is not well understood. This experiment modified the sentence–picture verification task to include nonspeech sounds with a complete factorial examination of all possible stimulus pairings. Participants studied simple stimuli–pictures, sentences, or sounds–and encoded the stimuli verbally, as visual images, or as auditory images. Participants then compared their encoded representations to verification stimuli–again pictures, sentences, or sounds–in a two-choice reaction time task. With some caveats, the encoding strategy appeared to be as important or more important than the external format of the initial stimulus in determining the speed of verification decisions. Findings suggested that: (1) auditory imagery may be distinct from verbal and visuospatial processing in working memory; (2) visual perception but not visual imagery may automatically activate concurrent verbal codes; and (3) the effects of hearing a sound may linger for some time despite recoding in working memory. We discuss the role of auditory imagery in dual-process theories of working memory.     

The role of modality: Auditory and visual distractors in Stroop interference

As a commonly used measure of selective attention, it is important to understand the factors contributing to interference in the Stroop task. The current research examined distracting stimuli in the auditory and visual modalities to determine whether the use of auditory distractors would create additional interference, beyond what is typically observed in the print-based Stroop task. Research by Cowan and Barron supported the additive effects of auditory and visual distractors; however, there is only one empirical demonstration of this finding to date. Using different versions of the Stroop colour-naming task, behavioural analyses of reaction times (RT) were conducted, along with distributional RT analyses. The results indicated that a combination of visual and auditory distraction did not lead to a larger interference effect than visually based distraction alone. These findings suggest that methodological issues may have influenced the prior finding of additive effects of the two modalities, and are discussed in relation to the word production architecture account of Stroop effects.     

Context effects in auditory implicit memory

The context effect in implicit memory is the finding that presentation of words in meaningful context reduces or eliminates repetition priming compared to words presented in isolation. Virtually all of the research on the context effect has been conducted in the visual modality but preliminary results raise the question of whether context effects are less likely in auditory priming. Context effects in the auditory modality were systematically examined in five experiments using the auditory implicit tests of word-fragment and word-stem completion. The first three experiments revealed the classical context effect in auditory priming: Words heard in isolation produced substantial priming, whereas there was little priming for the words heard in meaningful passages. Experiments 4 and 5 revealed that a meaningful context is not required for the context effect to be obtained: Words presented in an unrelated audio stream produced less priming than words presented individually and no more priming than words presented in meaningful passages. Although context effects are often explained in terms of the transfer-appropriate processing (TAP) framework, the present results are better explained by Masson and MacLeod's (2000) reduced-individuation hypothesis.     

It's not what you play,it's how you play it: Timbre affects perception of emotion in music

Salient sensory experiences often have a strong emotional tone, but the neuropsychological relations between perceptual characteristics of sensory objects and the affective information they convey remain poorly defined. Here we addressed the relationship between sound identity and emotional information using music. In two experiments, we investigated whether perception of emotions is influenced by altering the musical instrument on which the music is played, independently of other musical features. In the first experiment, 40 novel melodies each representing one of four emotions (happiness, sadness, fear, or anger) were each recorded on four different instruments (an electronic synthesizer, a piano, a violin, and a trumpet), controlling for melody, tempo, and loudness between instruments. Healthy participants (23 young adults aged 18–30 years, 24 older adults aged 58–75 years) were asked to select which emotion they thought each musical stimulus represented in a four-alternative forced-choice task. Using a generalized linear mixed model we found a significant interaction between instrument and emotion judgement with a similar pattern in young and older adults (p < .0001 for each age group). The effect was not attributable to musical expertise. In the second experiment using the same melodies and experimental design, the interaction between timbre and perceived emotion was replicated (p < .05) in another group of young adults for novel synthetic timbres designed to incorporate timbral cues to particular emotions. Our findings show that timbre (instrument identity) independently affects the perception of emotions in music after controlling for other acoustic, cognitive, and performance factors.     

When less is heard than meets the ear: Change deafness in a telephone conversation

During a conversation, we hear the sound of the talker as well as the intended message. Traditional models of speech perception posit that acoustic details of a talker's voice are not encoded with the message whereas more recent models propose that talker identity is automatically encoded. When shadowing speech, listeners often fail to detect a change in talker identity. The present study was designed to investigate whether talker changes would be detected when listeners are actively engaged in a normal conversation, and visual information about the speaker is absent. Participants were called on the phone, and during the conversation the experimenter was surreptitiously replaced by another talker. Participants rarely noticed the change. However, when explicitly monitoring for a change, detection increased. Voice memory tests suggested that participants remembered only coarse information about both voices, rather than fine details. This suggests that although listeners are capable of change detection, voice information is not continuously monitored at a fine-grain level of acoustic representation during natural conversation and is not automatically encoded. Conversational expectations may shape the way we direct attention to voice characteristics and perceive differences in voice.     

Temporal order perception of auditory stimuli is selectively modified by tonal and non-tonal language environments

The close relationship between temporal perception and speech processing is well established. The present study focused on the specific question whether the speech environment could influence temporal order perception in subjects whose language backgrounds are distinctively different, i.e., Chinese (tonal language) vs. Polish (non-tonal language). Temporal order thresholds were measured for both monaurally presented clicks and binaurally presented tone pairs. Whereas the click experiment showed similar order thresholds for the two language groups, the experiment with tone pairs resulted in different observations: while Chinese demonstrated better performance in discriminating the temporal order of two “close frequency” tone pairs (600 Hz and 1200 Hz), Polish subjects showed a reversed pattern, i.e., better performance for “distant frequency” tone pairs (400 Hz and 3000 Hz). These results indicate on the one hand a common temporal mechanism for perceiving the order of two monaurally presented stimuli, and on the other hand neuronal plasticity for perceiving the order of frequency-related auditory stimuli. We conclude that the auditory brain is modified with respect to temporal processing by long-term exposure to a tonal or a non-tonal language. As a consequence of such an exposure different cognitive modes of operation (analytic vs. holistic) are selected: the analytic mode is adopted for “distant frequency” tone pairs in Chinese and for “close frequency” tone pairs in Polish subjects, whereas the holistic mode is selected for “close frequency” tone pairs in Chinese and for “distant frequency” tone pairs in Polish subjects, reflecting a double dissociation of function.     

High emotional arousal and failures in reality monitoring: Pathways to auditory hallucinations in non‐psychotic children?

Recent research has confirmed the presence of auditory hallucinations in non‐psychotic children, with this research also suggesting that such hallucinations may be more common than previously thought. While auditory hallucinations in children have frequently been associated with high levels of emotional stress, there is still a poor understanding of how this stress may precipitate hallucinations, and why some children experience hallucinations while others seem not to. The current study assessed the association between high levels of trauma symptomatology, anxiety and depression, and the presence of hallucinations against matched controls. Results indicated that hallucinating children had significantly higher mean anxiety, depression and, in particular, re‐experiencing scores than did the children in the control group. These results were examined within the framework of reality monitoring, that is, the ability to distinguish between externally or internally generated sources of information. The notion of high levels of emotional distress decreasing the efficiency of reality monitoring and leading to the possibility of confusion between internally and externally generated stimuli was discussed, with the conclusion advanced that the misattribution of an externally generated source – either held as a memory or as a traumatic re‐experiencing – as an internally generated one, underlies hallucinatory experiences.