Stimulus categorization by brain-damaged patients

Patients with localized insult to the right hemisphere, or to either the anterior or the posterior portion of the left hemisphere, as well as neurologically intact controls, evaluated stimuli on a seven-point rating scale for their degree of category membership. The stimuli were taken from one of two continua, one composed of fruit and vegetable items, and the other of items differing in hue and shape. Different subsets of stimuli provided different contexts for the judgments of category membership. The two left-hemisphere groups showed anomalies in categorizing the fruit and vegetable items but not the perceptual items, while the reverse was true for the right-hemisphere patients. Moreover, both left-hemisphere groups demonstrated context effects in their judgments of the representativeness of the fruit and vegetable items, but differed in the way in which they responded to changing contexts. Left posterior patients demonstrated weak category boundaries and even reclassified items. In contrast, patients with left anterior damage showed highly categorical responses and less differentiation of items within a category. All groups showed striking context effects in judgments of perceptual items in terms of changes in representativeness ratings and the location of a category boundary. Alternative interpretations of the results are offered.     

The ABCs of categorical perception

Studies of speech perception first revealed a surprising discontinuity in the way in which stimulus values on a physical continuum are perceived. Data which demonstrate the effect in nonspeech modes have challenged the contention that categorical perception is a hallmark of the speech mode, but the psychophysical models that have been proposed have not resolved the issues raised by empirical findings. This study provides data from judgments of four sensory continua, two visual and two tactual-kinesthetic, which show that the adaptation level for a set of stimuli serves as a category boundary whether stimuli on the continuum differ by linear or logarithmic increments. For all sensory continua studied, discrimination of stimuli belonging to different perceptual categories was more accurate than discrimination of stimuli belonging to the same perceptual category. Moreover, shifts in the adaptation level produced shifts in the location of the category boundary. The concept of Adaptation-level Based Categorization (ABC) provides a unified account of judgmental processes in categorical perception without recourse to post hoc constructs such as implicit anchors or external referents.     

Postnatal development of respiratory and vocal responses during aversive classical conditioning in cats

Respiratory rate, respiration amplitude, and vocal responses were recorded in cats of different ages during classic conditioning. Vocal responses to the conditional stimulus (CS) appeared first in 8-week-old kittens, and became prominent at older ages. An increase in respiration rate occurred after the onset of the CS in cats of all ages. Similarly, the decrease of respiration amplitude was observed at all ages, but only in 8-week-old and older subjects did this response resemble an adult pattern. In 4-week-old kittens the response was characterized by an early and brief peak, suggesting an alpha conditional response (CR). Clear and significant discrimination between a warning and a safety signal was present in both respiratory and vocal responses after the age of 8 weeks.     

Intelligence and age as predictors of motor performance

The Yule-Oseretsky test of motor performance was administered to 10 ‘undifferentiated’ mentally-retarded adults, 10 normal children and 10 normal adults. In accordance with Denny's (1964) 3-group design, the children were matched on mental age with the retardates, the normal adults were matched on chronological age with the retardates, and the children and normal adults were matched on intelligence quotient. The results showed that mental age predicted performance on both fine and gross motor tasks, with the children and retarded adults both obtaining similar relatively-low scores.     

IS THERE A DISTINCTIVE QUANTUM THEOLOGY?

Quantum mechanics (QM) is a favorite area of physics to feature in “science and religion” discussions. We argue that this is at least partly because the arcane results of QM can be deployed to make big theological claims by the linguistic sleight of hand of “register switching”—sliding imperceptibly from technical into everyday language using the same vocabulary. We clarify the discussion by deploying the formal mapping of QM into classical statistical mechanics (CSM) via the mathematical device of “Wick rotation.” This equivalence between QM and CSM suggests caution in claiming distinctiveness for quantum theologizing. After outlining two areas in which quantum insights nevertheless resonate with longstanding themes in theological reflection (hiddenness and visualizability), we suggest that both QM and CSM point to a theology of science in which scientists participate in the divine gaze on creation as imago Dei.