“Seeing Rain”: Integrating phenomenological and Bayesian predictive coding approaches to visual hallucinations and self-disturbances (Ichstörungen) in schizophrenia

We present a schizophrenia patient who reports “seeing rain” with attendant somatosensory features which separate him from his surroundings. Because visual/multimodal hallucinations are understudied in schizophrenia, we examine a case history to determine the role of these hallucinations in self-disturbances (Ichstörungen). Developed by the early Heidelberg School, self-disturbances comprise two components: 1. The self experiences its own automatic processing as alien to self in a split-off, “doubled-I.” 2. In “I-paralysis,” the disruption to automatic processing is now outside the self in omnipotent agents. Self-disturbances (as indicated by visual/multimodal hallucinations) involve impairment in the ability to predict moment-to-moment experiences in the ongoing perception-action cycle. The phenomenological approach to subjective experience of self-disturbances complements efforts to model psychosis using the computational framework of hierarchical predictive coding. We conclude that self-disturbances play an adaptive, compensatory role following the uncoupling of perception and action, and possibly, other low-level perceptual anomalies.     

Social priming of hemispatial neglect affects spatial coding: Evidence from the Simon task

In the Simon effect (SE), choice reactions are fast if the location of the stimulus and the response correspond when stimulus location is task-irrelevant; therefore, the SE reflects the automatic processing of space. Priming of social concepts was found to affect automatic processing in the Stroop effect. We investigated whether spatial coding measured by the SE can be affected by the observer’s mental state. We used two social priming manipulations of impairments: one involving spatial processing - hemispatial neglect (HN) and another involving color perception - achromatopsia (ACHM). In two experiments the SE was reduced in the “neglected” visual field (VF) under the HN, but not under the ACHM manipulation. Our results show that spatial coding is sensitive to spatial representations that are not derived from task-relevant parameters, but from the observer’s cognitive state. These findings dispute stimulus-response interference models grounded on the idea of the automaticity of spatial processing.     

An analysis of confusion errors in many-to-one matching with temporal and nontemporal samples

In experiment 1, pigeons were trained to match temporal (2, 8, and 10 s of houselight) and location (feeder light, left key, center key illumination) samples to color comparison stimuli. Red choices were correct following the 2-s and feeder light, orange choices were correct following the 8-s and center key, and green choices were correct following the 10-s and left key. Samples that were harder to discriminate (8- vs 10-s, and left vs center key) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easier to discriminate (2- vs 8-s, and feeder light vs left key) were mapped onto comparisons that were hard to discriminate(red vs orange). The pattern of errors for temporal and location samples indicated that these samples were not represented by a common code even though they were associated with the same comparison stimuli. In experiment 2, the same pigeons were trained with visual samples in which samples that were hard to discriminate (triangle vs circle) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easy to discriminate(plus vs triangle) were mapped onto comparisons that were hard to discriminate (red vs orange). Following acquisition of the visual discrimination, the temporal samples were re-introduced and many-to-one training was continued. During delay testing, the pattern of errors for temporal and visual samples was equivalent and consistent with the hypothesis that visual samples were being coded in terms of the duration appropriate for the temporal sample with which it shared a common comparison response. Data from no-sample test sessions ruled out a simple response bias explanation of the data. The properties of common codes for temporal and nontemporal events can be somewhat flexible and more complicated than previously envisaged. Received: 21 January 1998 / Accepted after revision: 5 April 1998     

When expectation confounds iconic memory

In response to the methodological criticism (Bachmann & Aru, 2015) of the interpretation of their earlier experimental results (Mack, Erol, & Clarke, 2015) Mack, Erol, Clarke, and Bert (2016) presented new results that they interpret again in favor of the stance that an attention-free phenomenal iconic store does not exist. Here we once more question their conclusions. When their subjects were unexpectedly asked to report the letters instead of the post-cued circles in the 101th trial where letters were actually absent, they likely failed to see the empty display area because prior experience with letters in the preceding trials produced expectancy based illusory experience of letter-like objects.     

An improved spatial span test of visuospatial memory

In the widely used Corsi Block Test and Wechsler Spatial Span Tests, participants must reproduce sequences of blocks in the order touched by the examiner until two trials are missed at the same sequence length. The examiner records either the maximum number of blocks correctly reported or the total number of correct lists. Here, we describe a computerized spatial span test (C-SST) that uses psychophysical procedures to quantify visuospatial mean span (MnS) with sub-digit precision. Results from 187 participants ranging in age from 18 to 82 years showed that accuracy declined gradually with list length around the MnS (by ～30% per item). Simulation studies revealed high variance and biases in CBT and Wechsler measures, and demonstrated that the C-SST provided the most accurate estimate of true span (i.e., the sequence length producing 50% correct). MnS declined more rapidly with age than mean digit span (MnDS) measured in the same participants. Response times correlated with both MnS and MnDS scores. Error analysis showed that omission and transposition errors predominated, with weaker primacy and recency effects in spatial span than digit span testing. The C-SST improves the precision of spatial span testing and reveals significant differences between visuospatial and verbal working memory.     

Does It Matter Whether One Takes a Test on an iPad or a Desktop Computer?

To investigate possible iPad related mode effect, we tested 403 8th graders in Indiana, Maryland, and New Jersey under three mode conditions through random assignment: a desktop computer, an iPad alone, and an iPad with an external keyboard. All students had used an iPad or computer for six months or longer. The 2-hour test included reading, math, and writing items adapted from released NAEP 8th grade tests. Overall, no significant difference was found on the reading, math, or writing section scores or section response time among the three mode conditions. Further, roughly comparable numbers of students reportedly favored testing using an iPad or a desktop computer, but using a preferred mode did not lead to significantly higher section scores. These findings suggest that there is no noticeable disadvantage associated with taking a test on an iPad than on a desktop computer for experienced users of these two studied devices.     

Testing a direct mapping versus competition account of response dynamics in number comparison†

Tracking hand movements during number tasks has become a powerful method for disentangling competing models of numerical representation. In two experiments, participants used a computer mouse to choose whether presented numbers were greater than or less than 5. In Experiment 1, trajectories became more curved towards the incorrect response as targets approached the standard 5, indicating increasing response competition. However, trajectories showed a rightward bias modulated by numerical distance and target size, indicating a direct mapping between hand movement and an ordered, spatial number representation. In Experiment 2, I changed the direction of mouse movements bottom-to-top orientation to left-to-right. Trajectories again became more curved towards the incorrect response as targets approached 5, but this time, there was no modulation of trajectory bias by target size or distance. The results call into question a direct mapping account and instead lend support to a competition model of response dynamics in number comparison.     

Symbolic Representation by Pigeons

The capacity for symbolic representation is a prerequisite for the development of human language because words, the basic units of language, are symbols that represent things. But symbolic representation may also serve a nonlinguistic role of organizing events into categories having the same meaning, and such a capacity could have considerable survival value for many species. In a number of experiments, my co-workers and I have found that pigeons that are trained to treat two different stimuli similarly also learn that those stimuli are commonly represented and, thus, that they have the same meaning. We have demonstrated evidence for such common representations in a number of ways, but perhaps the most convincing is when pigeons learn a new association involving one of the presumed commonly represented stimuli, and without further training demonstrate that they have learned a similar association involving the other stimulus. Furthermore, we have found that when pigeons are trained to treat two stimuli similarly, one of those stimuli is represented in terms of the other. These results have implications not only for the generality of cognitive processes across species, but also for the generality of symbolic representation beyond language use.     

男性化与女性化对面孔偏好的影响—— 基于图像处理技术和眼动的检验

采用图像处理技术和眼动探讨了性别二态线索对面孔偏好的影响。实验1发现非面孔线索未掩蔽和掩蔽时, 感知男性化技术与原始照片条件下女性化的男性面孔更有吸引力和信任度; 性别二态技术条件下, 非面孔线索未掩蔽时男性化的男性面孔更有吸引力和信任度。实验2表明被试对男性面孔的平均瞳孔大小和注视次数均大于和多于女性面孔, 首次注视时间短于女性面孔; 被试对男性化面孔的首次注视时间和首次注视持续时间均长于女性化面孔。