Dana Schneider

Cognitive Load Disrupts Implicit Theory-of-Mind Processing:

Eye movements in Sally-Anne false-belief tasks appear to reflect the ability to implicitly monitor the mental states of other individuals (theory of mind, or ToM). It has recently been proposed that an early-developing, efficient, and automatically operating ToM system subserves this ability. Surprisingly absent from the literature, however, is an empirical test of the influence of domain-general executive processing resources on this implicit ToM system. In the study reported here, a dual-task method was employed to investigate the impact of executive load on eye movements in an implicit Sally-Anne false-belief task. Under no-load conditions, adult participants displayed eye movement behavior consistent with implicit belief processing, whereas evidence for belief processing was absent for participants under cognitive load. These findings indicate that the cognitive system responsible for implicitly tracking beliefs draws at least minimally on executive processing resources. Thus, even the most low-level processing of beliefs appears to reflect a capacity-limited operation.

What do we know about implicit false-belief tracking?

There is now considerable evidence that neurotypical individuals track the internal cognitions of others, even in the absence of instructions to do so. This finding has prompted the suggestion that humans possess an implicit mental state tracking system (implicit Theory of Mind, ToM) that exists alongside a system that allows the deliberate and explicit analysis of the mental states of others (explicit ToM). Here we evaluate the evidence for this hypothesis and assess the extent to which implicit and explicit ToM operations are distinct. We review evidence showing that adults can indeed engage in ToM processing even without being conscious of doing so. However, at the same time, there is evidence that explicit and implicit ToM operations share some functional features, including drawing on executive resources. Based on the available evidence, we propose that implicit and explicit ToM operations overlap and should only be considered partially distinct.

Attentional Load Asymmetrically Affects Early Electrophysiological Indices of Visual Orienting

Recent behavioral studies suggest that asymmetries in visuospatial orienting are modulated by changes in the demand on nonspatial components of attention, but the brain correlates of this modulation are unknown. We used scalp-recorded event-related potentials to examine the influence of central attentional load on neural responses to lateralized visual targets. Forty-five participants were required to detect transient, unilateral visual targets while monitoring a stream of alphanumeric stimuli at fixation, in which the target was defined either by a unique feature (low load) or by a conjunction of features (high load). The earliest effect of load on spatial orienting was seen at the latency of the posterior N1 (190-240 ms). The commonly observed N1 enhancement with contralateral visual stimulation was attenuated over the right hemisphere under high load. Source analysis localized this effect to occipital and inferior parietal regions of the right hemisphere. In addition, we observed perceptual enhancement with increasing load within the focus of attention (fixation) at an earlier stage (P1, 90-140 ms) than has previously been reported. These data support the view that spatial asymmetries in visual orienting are modulated by nonspatial attention due to overlapping neural circuits within the right hemisphere.

Spontaneous but not explicit processing of positive sentences impaired in Asperger's syndrome: Pupillometric evidence

Emotional prosody provides important cues for understanding the emotions of others in every day communication. Aspergers syndrome (AS) is a developmental disorder characterised by pronounced deficits in socio-emotional communication, including difficulties in the domain of prosody processing. We measured pupillary responses as an index of emotional prosodic processing when 15 participants with AS and 19 non-clinical control participants listened to positive, negative and neutral prosodic sentences. This occurred under a spontaneous and an explicit task instruction. In the explicit processing condition, the AS group and the non-clinical controls showed increased pupil dilations to positively and negatively intoned sentences when judging the valence of that prosodic sentence. This suggests higher processing demands for emotionally arousing information, as the effect was not found in comparison to neutrally intoned sentences. In the spontaneous processing condition, controls also responded with increased pupil dilations to positively intoned sentences, whilst individuals with AS showed increased pupil dilations to negative sentences. The latter result is further supported by diminished ratings of emotionally intense sentences in the AS group compared to healthy controls. Perception and recognition of positively valenced sentences in individuals with AS appears impaired and dependent on the general task set-up. Diminished pupil dilations in spontaneous positive processing conditions as well as reduced positive valence ratings give strong indications for a general negative processing bias of verbal information for adult individuals diagnosed with AS.

Syllable structure is modulating the optimal viewing position in visual word recognition

Abstract There is an ongoing debate in cognitive psychology as to whether syllables have to be seen as functional units not only for speech perception and production, but also for the process of silent reading or visual word recognition. For the present study, we used a perceptive identification task where single disyllabic 5-letter German words were briefly presented to the participants for 50 or 60 milliseconds. The percentage of errors in identifying these stimuli was the dependent variable. During presentation in the experiment we manipulated the viewing position for these items, so that initial fixation for each repeatedly presented word varied systematically across all five letter positions. Typically, for such manipulations, word recognition is best when initial fixation is at a position slightly left from the word center — a finding referred to as the optimal viewing position effect. We found that the shape of the optimal viewing position function is sensitive to syllabic structure: The optimal viewing position shifted one letter position to the right with increasing initial syllable length (two vs. three letters in our stimulus material). This finding suggests that efficient reading benefits from a very early processing of syllabic information. It corroborates other recent empirical findings suggesting that also during silent reading orthographic word forms are automatically segmented into their syllabic constituents.