A physiological marker of recognition memory in adults with autism spectrum disorder? The Pupil Old/New Effect

This study investigated the pupil Old/New effect in individuals with Autism Spectrum Disorder (ASD) and typical development (TD). Participants studied verbal and visual meaningful and meaningless materials in black and white on a computer screen. Pupil sizes were measured while participants performed a Remember (episodic memory with context) /Know (semantic memory, no context) recognition memory test. ASD compared to TD individuals showed significantly reduced recognition rates for all materials. Both groups showed better memory for visual compared to verbal (picture superiority effect) and meaningful compared to meaningless materials. A pupil size ratio (pupil size for test item divided by baseline) for old (studied) and new (unstudied) materials indicated larger pupils for old compared to new materials only for the TD but not the ASD group. Pupil size in response to old versus new items was positively related to recognition accuracy, confirming that the pupil Old/New effect reflects a memory phenomenon in the ASD group. In addition, this study suggests an involvement of the noradrenergic neurotransmitter system in the abnormal hippocampal functioning in ASD. Implications of these findings as well as their underlying neurophysiology will be discussed in relation to current theories of memory in ASD

Differential fear conditioning in Asperger's syndrome: Implications for an amygdala theory of autism

Since the first descriptions of individuals with autism spectrum disorders (ASD), abnormalities in socio-emotional behaviours have been described as amongst the most characteristic clinical features of this condition. Current evidence in this area suggests that individuals with ASD experience difficulties in the perception and expression of emotions within the social domain. The causes for these emotional difficulties are, however, still poorly understood. At the developmental level, it is unclear whether emotional disturbances constitute a primary feature of the clinical presentation of ASD or whether they are secondary to abnormalities in other areas of cognition. At the neurobiological level, it is still debated to what extent abnormalities of the limbic system, in particular the amygdala, may be responsible for the emotional disturbances characterising ASD. Here we show that a group of individuals with Asperger's syndrome exhibit a pattern of abnormality in differentially acquiring fear, which suggests that their fear responses are atypically modulated by conditioned and non-conditioned stimuli. On the basis of these results and the existing literature we suggest that ASD may be characterised by atypicalities in the integration of physiological and cognitive aspects of emotional experiences which we argue arise because of poor connectivity between the amygdala and functionally associated cortical areas

The influence of schizotypal traits on attention under high perceptual load

Schizophrenia Spectrum Disorders (SSD) are known to be characterised by abnormalities in attentional processes, but there are inconsistencies in the literature that remain unresolved. This article considers whether perceptual resource limitations play a role in moderating attentional abnormalities in SSD. According to perceptual load theory, perceptual resource limitations can lead to attenuated or superior performance on dual-task paradigms depending on whether participants are required to process, or attempt to ignore, secondary stimuli. If SSD is associated with perceptual resource limitations, and if it represents the extreme end of an otherwise normally distributed neuropsychological phenotype, schizotypal traits in the general population should lead to disproportionate performance costs on dual-task paradigms as a function of the perceptual task demands. To test this prediction, schizotypal traits were quantified via the Schizotypal Personality Questionnaire (SPQ) in 74 healthy volunteers, who also completed a dual-task signal detection paradigm that required participants to detect central and peripheral stimuli across conditions that varied in the overall number of stimuli presented. The results confirmed decreasing performance as the perceptual load of the task increased. More importantly, significant correlations between SPQ scores and task performance confirmed that increased schizotypal traits, particularly in the cognitive-perceptual domain, are associated with greater performance decrements under increasing perceptual load. These results confirm that attentional difficulties associated with SSD extend sub-clinically into the general population and suggest that cognitive-perceptual schizotypal traits may represent a risk factor for difficulties in the regulation of attention under increasing perceptual load

Episodic but not semantic order memory difficulties in autism spectrum disorder: Evidence from the Historical Figures Task

Considerable evidence suggests that the episodic memory system operates abnormally in autism spectrum disorder (ASD) whereas the functions of the semantic memory system are relatively preserved. Here we show that the same dissociation also applies to the domain of order memory. We asked adult participants to order the names of famous historical figures either according to their chronological order in history (probing semantic memory) or according to a random sequence shown once on a screen (probing episodic memory). As predicted, adults with ASD performed less well than age- and IQ-matched comparison individuals only on the episodic task. This observation is of considerable importance in the context of developmental theory because semantic and episodic order memory abilities can be dissociated in typically developing infants before they reach the age at which the behavioural markers associated with ASD are first apparent. This raises the possibility that early emerging memory abnormalities play a role in shaping the developmental trajectory of the disorder. We discuss the broader implications of this possibility and highlight the urgent need for greater scrutiny of memory competences in ASD early in development

Exemplar variance supports robust learning of facial identity

Differences in the visual processing of familiar and unfamiliar faces have prompted considerable interest in face learning, the process by which unfamiliar faces become familiar. Previous work indicates that face learning is determined in part by exposure duration; unsurprisingly, viewing faces for longer affords superior performance on subsequent recognition tests. However, there has been further speculation that exemplar variation, experience of different exemplars of the same facial identity, contributes to face learning independently of viewing time. Several leading accounts of face learning, including the averaging and pictorial coding models, predict an exemplar variation advantage. Nevertheless, the exemplar variation hypothesis currently lacks empirical support. The present study therefore sought to test this prediction by comparing the effects of unique exemplar face learning - a condition rich in exemplar variation - and repeated exemplar face learning œ a condition that equates viewing time, but constrains exemplar variation. Crucially, observers who received unique exemplar learning displayed better recognition of novel exemplars of the learned identities at test, than observers in the repeated exemplar condition. These results have important theoretical and substantive implications for models of face learning and for approaches to face training in applied contexts

Factors affecting conscious awareness in the recollective experience of adults with Asperger's syndrome

Bowler, Gardiner, and Grice (2000a) have shown a small but significant impairment of autonoetic awareness or remembering involved in the episodic memory experiences of adults with Asperger’s syndrome. This was compensated by an increase in experiences of noetic awareness or knowing. The question remains as to whether the residual autonoetic awareness in Asperger individuals is qualitatively the same as that of typical comparison participants. Three experiments are presented in which manipulations that have shown differential effects on different kinds of conscious awareness in memory in typical populations are employed with a sample of adults with Asperger’s syndrome. The results suggest that the experiences of remembering reported by such individuals, although reduced in quantity, are qualitatively similar to those seen in the typical population. The results are discussed in the context of current theories of awareness in episodic memory

The Interplay between Emotion and Cognition in Autism Spectrum Disorder: Implications for Developmental Theory

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder that is clinically defined by abnormalities in reciprocal social and communicative behaviors and an inflexible adherence to routinised patterns of thought and behavior. Laboratory studies repeatedly demonstrate that autistic individuals experience difficulties in recognizing and understanding the emotional expressions of others and naturalistic observations show that they use such expressions infrequently and inappropriately to regulate social exchanges. Dominant theories attribute this facet of the ASD phenotype to abnormalities in a social brain network that mediates social-motivational and social-cognitive processes such as face processing, mental state understanding, and empathy. Such theories imply that only emotion related processes relevant to social cognition are compromised in ASD but accumulating evidence suggests that the disorder may be characterized by more widespread anomalies in the domain of emotions. In this review I summarize the relevant literature and argue that the social-emotional characteristics of ASD may be better understood in terms of a disruption in the domain-general interplay between emotion and cognition. More specifically I will suggest that ASD is the developmental consequence of early emerging anomalies in how emotional responses to the environment modulate a wide range of cognitive processes including those that are relevant to navigating the social world

The Witness-Aimed First Account (WAFA): a new technique for interviewing autistic witnesses and victims

Autistic people experience social communication difficulties alongside specific memory difficulties that can impact their ability to recall episodic events. Police interviewing techniques do not take account of these differences, and so are often ineffective. Here we introduce a novel Witness-Aimed First Account (WAFA) interview technique, designed to better support autistic witnesses by diminishing socio-cognitive and executive demands through encouraging participants to generate and direct their own discrete, parameter-bound event topics, before freely recalling information within each parameter-bound topic. Since witnessed events are rarely cohesive stories with a logical chain of events, we also explored witnesses’ recall when the narrative structure of the to-be-remembered event was lost. Thirty-three autistic and 30 typically developing (TD) participants were interviewed about their memory for two videos depicting criminal events. Clip segments of one video were ‘scrambled’, disrupting the event’s narrative structure; the other video was watched intact. Although both autistic and TD witnesses recalled fewer details with less accuracy from the scrambled video, WAFA interviews resulted in more detailed and accurate recall from autistic and TD witnesses, for both scrambled and unscrambled videos. The WAFA technique may be a useful tool to improve autistic and TD witnesses’ accounts within a legally appropriate, non-leading framework

Short-term memory in autism spectrum disorder

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items

Effects of related and unrelated context on recall and recognition by adults with high-functioning autism spectrum disorder

Memory in autism spectrum disorder (ASD) is characterised by greater difficulties with recall rather than recognition and with a diminished use of semantic or associative relatedness in the aid of recall. Two experiments are reported that test the effects of item-context relatedness on recall and recognition in adults with highfunctioning ASD (HFA) and matched typical comparison participants. In both experiments, participants studied words presented inside a red rectangle and were told to ignore context words presented outside the rectangle. Context words were either related or unrelated to the study words. The results showed that relatedness of context enhanced recall for the typical group only. However, recognition was enhanced by relatedness in both groups of participants. On a behavioural level, these findings confirm the Task Support Hypothesis (Bowler, Gardiner & Berthollier, 2004), which states that individuals with ASD will show greater difficulty on memory tests that provide little support for retrieval. The findings extend this hypothesis by showing that it operates at the level of relatedness between studied items and incidentally-encoded context. By showing difficulties in memory for associated items, the findings are also consistent with conjectures that implicate medial temporal lobe and frontal lobe dysfunction in the memory difficulties of individuals with ASD