EXPRESS: Fooling System 1 in the field of perception: Failure to Intuitively Detect Attribute Substitution in the Flushtration Count Illusion

To facilitate our interactions with the surroundings, the human brain sometimes reshapes the situations that it faces in order to simplify them. This phenomenon has been widely studied in the context of reasoning, especially through the attribute substitution error. It has however been given much less attention in the field of perception. Recent research on the bat-and-ball problem suggests that reasoners are able to intuitively detect attribute substitution errors. Using a perceptual illusion drawn from the field of magic, we investigate the extent to which a perceptual form of attribute substitution depends on executive resources and can be detected. We also investigate the relationship between susceptibility to attribute substitution error in the flushtration count illusion and in a French adaptation of the bat-and ball problem. Finally, we investigate the link between the intuitive cognitive style (assessed by the Cognitive Reflection Test) and the susceptibility to the flushtration count illusion. Our results suggest that participants do not detect perceptual attribute substitution error, that this phenomenon could be independent of the executive resources allocated to the task, and could rest on mechanisms distinct from those that produce errors in reasoning. We discuss differences between these two phenomena, and factors that may explain them.

Common computational principle for vibro-tactile pitch perception in mouse and human

We live surrounded by vibrations generated by moving objects. These oscillatory stimuli can produce sound (i.e. airborne waves) and propagate through solid substrates. Pitch is the main perceptual characteristic of sound, and a similar perceptual attribute seems to exist in the case of substrate vibrations: vibro-tactile pitch. Here, we establish a mechanistic relationship between vibro-tactile pitch perception and the actual physical properties of vibrations using behavioral tasks, in which vibratory stimuli were delivered to the human fingertip or the mouse forelimb. The resulting perceptual reports were analyzed with a model demonstrating that physically different combinations of vibration frequencies and amplitudes can produce equal pitch perception. We found that the perceptually indistinguishable but physically different stimuli follow a common computational principle in mouse and human. It dictates that vibro-tactile pitch perception is shifted with increases in amplitude toward the frequency of highest vibrotactile sensitivity. These findings suggest the existence of a fundamental relationship between the seemingly unrelated concepts of spectral sensitivity and pitch perception.

Interactive Processing of Timbre Dimensions: An Exploration with Event-related Potentials

Timbre characterizes the identity of a sound source. On psychoacoustic grounds, it has been described as a multidimensional perceptual attribute of complex sounds. Using Garner's interference paradigm, we found in a previous behavioral study that three timbral dimensions exhibited interactive processing. These timbral dimensions acoustically corresponded to attack time, spectral centroid, and spectrum fine structure. Here, using event-related potentials (ERPs), we sought neurophysiological correlates of the interactive processing of these dimensions of timbre. ERPs allowed us to dissociate several levels of interaction, at both early perceptual and late stimulus identification stages of processing. The cost of filtering out an irrelevant timbral dimension was accompanied by a late negative-going activity, whereas congruency effects between timbre dimensions were associated with interactions in both early sensory and late processing stages. ERPs also helped to determine the similarities and differences in the interactions displayed by the different pairs of timbre dimensions, revealing in particular variations in the latencies at which temporal and spectral timbre dimensions can interfere with the processing of another spectral timbre dimension.

Separate Neural Processing of Timbre Dimensions in Auditory Sensory Memory

Timbre is a multidimensional perceptual attribute of complex tones that characterizes the identity of a sound source. Our study explores the representation in auditory sensory memory of three timbre dimensions (acoustically related to attack time, spectral centroid, and spectrum fine structure), using the mismatch negativity (MMN) component of the auditory event-related potential. MMN is elicited by a discriminable change in a sound sequence and reflects the detection of the discrepancy between the current stimulus and traces in auditory sensory memory. The stimuli used in the present study were carefully controlled synthetic tones. MMNs were recorded after changes along each of the three timbre dimensions and their combinations. Additivity of unidimensional MMNs and dipole modeling results suggest partially separate MMN generators for different timbre dimensions, reflecting their mainly separate processing in auditory sensory memory. The results expand to timbre dimensions a property of separation of the representation in sensory memory that has already been reported between basic perceptual attributes (pitch, loudness, duration, and location) of sound sources.

Progressive knowledge loss: A longitudinal case study

The evolution of the progressive loss of semantic knowledge of a patient, VZ, with lesions mainly affecting the infero-medial temporal lobes, was followed for two years. At the beginning of the study VZ's performance was mainly characterized by a category-specific deficit for living things and a modality-specific deficit for perceptual attribute knowledge. As time went on, VZ's disorder affected all categories by changing the relationship between category and attribute knowledge. Data show that dissociations may change in the course of progressive cognitive breakdown, depending on both degeneration stage and task demands. VZ's performance is discussed in the light of the most influential theoretical accounts. Methodological suggestions regarding longitudinal studies of degenerative patients are also put forward. (JINS, 2006,12, 275–284.)