Sequence learning by action and observation: evidence for separate mechanisms.

In the Serial Reaction Time (SRT) task, participants respond to a set of stimuli the order of which is apparently random, but which consists of repeating sub-sequences. Participants can become sensitive to this regularity, as measured by an indirect test of reaction time, but can remain apparently unaware of the sequence, as measured by direct tests of prediction or recognition. Some researchers have claimed that this learning may take place by observation alone. We suggest that observational learning may be due to explicit acquired knowledge of the sequence, and is not mediated by the same processes which give rise to learning by action. In Expt 1, we show that it is very difficult to acquire explicit sequence knowledge under dual task conditions, even when participants are told that a regular sequence exists. In Expt 2, we use the same conditions to compare actors, who respond to the sequence during learning, and observers, who merely watch the stimuli. Furthermore, we manipulate the salience of the sequence, in order to encourage learning. There is no evidence of observational learning in these conditions, despite the usual effects of learning being demonstrated by actors. In Expt 3, we show that observational learning does occur, but only when observers have no secondary task and even then only reliably for a sequence which has been made salient by chunking subcomponents. We conclude that sequence learning by observation is mediated by explicit processes, and is eliminated under conditions which support learning by action, but make it difficult to acquire explicit knowledge.

Learning complex sequences: no role for observation?

Two experiments examined performance in a sequence learning task. Participants were trained on a repeating sequence which was presented as a visual display and learning was measured via the increase in reaction time to respond to a new sequence. Some participants made a response to each stimulus while others merely observed the sequence. In Experiment 1 participants responding to the display via a keypress showed learning, but those merely observing did not. Five possible reasons for the failure to find observational learning were considered and the Experiment 2 attempted to resolve these. This second experiment confirmed the findings of Experiment 1 in a non-spatial sequence display using a cover story which encouraged attention to the display but not rule-search strategies. The results are discussed in relation to applied and theoretical aspects of implicit learning.

Priming the access to names of famous faces.

There is a continuing controversy in models of face identification concerning the level of access to names relative to semantic information. In order to determine whether names are accessed sequentially after or in parallel to semantic information, we studied participants' speeded decisions about famous faces that were primed by partial semantic or partial name information. Decisions that required the access to the celebrity's name (one or more forename syllables, Expt 1) were significantly primed by partial name primes (initials or name fragments). However, at variance with sequential stage models, no reliable priming was observed by partial semantic primes (information about nationality, occupation, or whether a person was dead or alive). Moreover, there was a clear and consistent priming effect by partial semantic primes if the task was a nationality (British or American) decision that required the access to semantic information (Expt 2), demonstrating the effectiveness of these primes. The effects of partial name primes on nationality decisions were less consistent, with a significant effect for name fragments but not initials. However, effects of name primes were generally greater for syllable decisions than nationality decisions, and effects of semantic primes were generally greater for nationality decisions than syllable decisions. Taken together, these results favour a model of parallel rather than sequential access and suggest some degree of independence in the access to personal semantics and names.

Incidental learning of real-world regularities.

The large literature on incidental learning relies almost exclusively on laboratory experiments. Whenever researchers have attempted to demonstrate incidental learning of real-world regularities, they have typically failed to show learning. For example, it is well established that people do not learn regularities in everyday objects, such as the left-right orientation of faces on coins, despite a very large exposure to them. In this report, we examine this apparent contradiction. We argue that most studies exploring real-life incidental learning use tests that are not as sensitive to low-confidence information as those traditionally used in laboratory tasks. Using more sensitive measures, we show that it is possible to learn regularities from British and Japanese cultural life as a direct result of exposure to these regularities. Further, confidence measures suggest that although the information may be acquired incidentally, it can be expressed with and without concomitant awareness of that knowledge.

Asymmetric dependencies in perceiving identity and emotion: experiments with morphed faces.

We investigated whether an asymmetric relationship between the perception of identity and emotional expressions in faces (Schweinberger & Soukup, 1998) may be related to differences in the relative processing speed of identity and expression information. Stimulus faces were morphed across identity within a given emotional expression, or were morphed across emotion within a given identity. In Experiment 1, consistent classifications of these images were demonstrated across a wide range of morphing, with only a relatively narrow category boundary. At the same time, classification reaction times (RTs) reflected the increased perceptual difficulty of the morphed images. In Experiment 2, we investigated the effects of variations in the irrelevant dimension on judgments of faces with respect to a relevant dimension, using a Garner-type speeded classification task. RTs for expression classifications were strongly influenced by irrelevant identity information. In contrast, RTs for identity classifications were unaffected by irrelevant expression information, and this held even for stimuli in which identity was more difficult and slower to discriminate than expression. This suggests that differences in processing speed cannot account for the asymmetric relationship between identity and emotion perception. Theoretical accounts proposing independence of identity and emotion perception are discussed in the light of these findings.

Spermatic-cord block improves analgesia for day-case testicular surgery.

OBJECTIVE: To assess whether the use of a spermatic-cord block contributes any additional analgesia to that of a conventional analgesic regimen in day-case testicular surgery. PATIENTS AND METHODS: In a randomized, double-blind controlled study, 48 patients undergoing day-case testicular surgery received general anaesthesia together with fentanyl and diclofenac for analgesia. In addition, 22 of these patients received 10 mL of 0.5% plain bupivacaine into the spermatic cord at the conclusion of surgery. Visual-analogue pain scores were recorded for each group over the following 24 h. RESULTS: The visual-analogue pain scores were significantly lower in the immediate recovery period in patients receiving the spermatic-cord block. CONCLUSION: The spermatic-cord block reduced discomfort in the immediate post-operative period in patients undergoing testicular surgery and the procedure should be encouraged to improve the quality of post-operative pain management in such procedures.

Investigating the relation between imagery and perception: evidence from face priming.

The relation between imagery and perception was investigated in face priming. Two experiments are reported in which subjects either saw or imagined the faces of celebrities. They were later given a speeded perceptual test (familiarity judgement to pictures of celebrities) or a speeded imagery test (in which they were told the names of celebrities and asked to make a decision about their appearance). Seeing faces primed the perceptual test, and imaging faces primed the imagery test; however, there was no priming between seeing and imaging faces. These results show that perception and imagery can be dissociated in normal subjects. In two further experiments, we examined the effects of imaging faces on a subsequent face-naming task and on a task requiring familiarity judgements to partial faces. Both these tasks were facilitated by prior imaging of faces. These results are discussed in relation to those of McDermott & Roediger (1994), who found that imagery promoted object priming in a perceptual test involving naming partial line drawings. The implications for models of face recognition are also discussed.

The relationships between psychometric intelligence and learning in an explicit and an implicit task.

An experiment is reported examining the relation of implicit grammar learning and series completion tasks to a standard measure of psychometric intelligence, the Wechsler Adult Intelligence Scale-Revised (WAIS-R; D. Wechsler, 1981). The results replicate and extend an earlier study by A. S. Reber, F. F. Walkenfeld, and R. Hernstadt (1991) and provide the following support for the differences between explicit and implicit tasks: (a) The implicit task was less strongly related to Full Scale IQ, and (b) the implicit task appeared to be independent of age. The implicit and explicit tasks exhibited a quite different pattern of relations to the factors known to underlie WAIS-R performance. Although both tasks showed significant links with a Perceptual Organization factor, only the series completion task showed a significant link with the Attention factor.

An instrument for the non-invasive objective assessment of velar function during speech.

This paper describes the development of a non-invasive, computer-based, clinical instrument that infers velar function by way of the measurement of nasal and oral airflow. The design criteria of the instrument were based upon a wide ranging review of current practice and available techniques. The instrument measures and displays both nasal and oral airflow, along with the envelope of the speech sound waveform. This allows the clinician to determine whether airflow is associated with oral or nasal airflow and, hence, to infer the position of the velum. Preliminary clinical trials suggest that the instrument provides valuable objective information about the movement of the soft palate, particularly within the time domain. Hence, it is believed that the device provides additional information for the assessment of velar function, complementing those techniques currently employed.

Assessment in the treatment of hypernasal speech with motor neuron disease: a clinical report.

The application of nasal anemometry in this patient's treatment proved to be of value in obtaining an objective assessment of this intervention. Nasal anemometry may be of use in other situations, for example, (1) in preassessment and postassessment of cleft palate surgery and surgical interventions to improve the velopharyngeal seal (such as pharyngoplasty), (2) in the evaluation of nasalized speech with conventional speech therapy, (3) in the evaluation of nasalized speech by use of a palatal training appliance, and (4) in the investigation of snoring.

Lumbar epidural morphine infusions for children undergoing cardiac surgery.

OBJECTIVE: To determine whether outcomes and costs in children undergoing cardiac surgery are affected by the method of postoperative pain management. DESIGN: Retrospective, case control. SETTING: Tertiary care children's hospital in a university setting. PARTICIPANTS: Two groups of children undergoing cardiac surgery for palliation or repair of congenital heart disease oer a 21-month period between January 1993 and September 1994. INTERVENTIONS: Lumbar epidural morphine infusions (LEM) in one group, and IV opioid (IVO) medication in the other for postoperative pain control. MEASUREMENTS AND MAIN RESULTS: Hospital courses of 27 LEM patients and 27 IVO patients were analyzed. In LEM patients, epidural catheters were placed following anesthetic induction, but before anticoagulation. A bolus of 50 micrograms/kg of preservative-free morphine sulfate was administered through the catheter, followed by a continuous infusion at 3 to 4 micrograms/kg/h for 22 to 102 (median, 46) hours postoperatively. The IVO patients received 50 micrograms/kg, IV, of fentanyl before incision followed by a continuous infusion at 0.3 microgram/kg/min. The fentanyl infusion rate was decreased to 0.1 microgram/kg/min postoperatively and maintained for 24 hours. Although the LEM group was demographically similar to the IVO group, times to tracheal extubation, transfer from the intensive care unit, and resumption of regular diet were significantly shorter in LEM patients. LEM and IVO patients received similar amounts of fentanyl during surgery (10.4 +/- 19.3 micrograms/kg/h v 13.7 +/- 8.1 micrograms/kg/h, p = 0.4). However, during postoperative recovery, LEM patients who were extubated late received significantly less supplemental opioid medication than IVO patients extubated late during the first 5 postoperative days. No complications related to dural puncture, bleeding into the epidural space, or respiratory depression were encountered. Pruritus and nausea/vomiting were the most commonly reported morbidities in both groups. Fifty-six percent (15/27) of LEM patients and 41% of IVO patients reported pruritus (p = 0.4). There was no significant difference in the incidence of nausea and vomiting between the groups (34% v 30%, respectively). CONCLUSIONS: Given the present methodologic limitations, the authors found improved outcomes only in LEM patients extubated late compared with IVO patients. Randomized, prospective studies to evaluate this conclusion and to determine the comparative efficacy and safety of LEM infusions are in progress.

Globus pharyngis, personality, and psychological distress in the general population.

The authors approached 1,158 middle-aged women, who were assessed for the presence of the globus sensation in the prior 3 months. Seventy globus "cases" (6.0%) were identified. Twenty-eight women with globus and 35 control subjects completed a series of questionnaires designed to assess personality traits and psychological distress. The globus subjects were significantly higher on neuroticism and low on extra-version and had significantly elevated levels of psychological distress, including anxiety, low mood, and somatic concern when compared with the control subjects. Severity of throat symptoms, but not personality or psychological distress scores, predicted the degree of medical help sought for the symptom.

The auditory evoked potential and paediatric anaesthesia.

We have examined the raw EEG activity and auditory evoked responses (AER) in 35 children, aged 3 days to 13 yr (median 1.5 yr), undergoing general anaesthesia for routine surgery. Binaural stimuli were presented at a frequency of 6.12 Hz and the EEG was recorded and stored using the Northwick Park auditory evoked response software. AER were generated by averaging 512 sweeps each of 125-ms duration. In children less than 2 yr of age, the AER was often irregular, whereas children older than 2 yr had AER patterns similar to those in adults. In children less than 2 yr, regular artefact activity was superimposed on the background EEG which was at the same frequency as the instantaneous heart rate and which was often identifiable as the ECG. We conclude that the AER may be unreliable in children less than 2 yr of age, and modification of current methodology may be required if this technique is to become useful in paediatric anaesthetic practice.

A study of laryngeal mask inflation. Pressures exerted on the pharynx.

Laryngeal mask airway cuff inflation pressures were measured when inflated with the same volume of gas firstly in free space and then in position in the pharynx. A large difference in these pressures was observed and this was related to pharyngeal mucosal perfusion pressure. This study shows that it may be easy to produce pressures on the pharyngeal mucosa in excess of the critical perfusion pressure and thus potentiate mucosal trauma. Furthermore, laryngeal mask cuff pressures were measured at intervals during anaesthesia and were found to rise by a significant amount if room air was used as the cuff inflating gas. This effect could, however, be reversed if inspired gas was used to inflate the mask cuff. We conclude that care must be taken when inflating the laryngeal mask cuff if postoperative morbidity is to be avoided and also that it may not be necessary to use as high a volume of inflating gas as has been recommended during spontaneous respiration.