The role of eye-fixation research in cognitive psychology

Eye-fixation research can be used to address issues of theoretical interest in several areas of cognitive psychology, such as linguistic processing, spatial processing, and reading. The eye-fixation behavior can lead to processing models, assuming that the eye fixates the referent of the symbol being operated on.     

Pathological left-handedness and familial sinistrality in relation to degree of mental retardation

The relationship between personal and familial hand preference and mental retardation was examined. Six unimanual tasks were performed by 232 subjects within four mental retardation severity groups. Family handedness histories were obtained. Right hand preference varied inversely with severity of mental retardation. The handedness of mentally retarded groups at the different functional levels paralleled, but tended much more to the sinistral, than that of the corresponding parent groups. The parent-proband handedness correlations were largely insignificant, especially in lower functioning groups. The findings support both pathological left-handedness theory and an association between brain damage causing mental retardation and familial sinistrality.     

Conditioning of the microcirculation in the rat

The serotonin-catecholamine balancing mechanism maintains normal vascular tonus and permeability of the microcirculation. Serotonin provokes local vasodilatation and increases capillary permeability in the skin of rats. Released or injected catecholamines inhibit the serotonin-induced peripheral hemodynamic alterations. Following eleotroconvulsive treatment (ECT) (US), there is a catecholamine release and the microcirculatory response to serotonin does not occur. When the administration of a visual stimulus (in six consecutive occasions) proceedingly coincided with the administration of the ECT, it was noted that the light became an effective stimulus for this system. Light alone is an indifferent stimulus to catecholamine release. Thus, the inhibition of the serotonin-induced vasodilatation by ECT (via catecholamine release) became conditioned to the visual-conditional stimulus. Since the net effect of extrinsic serotonin depends on free catecholamines at the vascular bed, the intensity of the serotonin-induced vascular response reflects alterations in the chemical balancing mechanism. This mechanism can be conditioned with the present technique. The result indicates that there is central nervous system mediation.     

Divergent Thinking Styles of the Hemispheres: How Syllogisms Are Solved during Transitory Hemisphere Suppression

Psychiatric patients solved syllogisms while recovering from transitory ictal suppression of one hemisphere by electroconvulsive therapy (ECT). The premises were familiar or unfamiliar, true or false. While the right hemisphere was suppressed, syllogisms were usually solved by theoretical, deductive reasoning even when the factual answer was known a priori, the premises were obviously false and the conclusions were absurd. While their left hemisphere was suppressed, the same subjects applied their prior knowledge; if the syllogism content was unfamiliar or false, they refused to answer. We postulate a left-hemisphere mechanism capable of decontextualized mental operations and a right-hemisphere mechanism, the operation of which is context-bound and incapable of abstraction. We show that each hemisphere tends to overextend its perspective on the problem and that in the intact brain they both contribute to an extent that depends on the characteristics of the problem at hand.     

The demonstration of dichoptic flicker effects by use of polaroid

A simple way of setting up dichoptic flicker with variable phase relationship is described. Sine wave flashes result, and for these, as for square waves, Sherrington's hypothesis of independent testing for intermittence of inputs to each eye is approximately borne out. Observations of the attributes of these two modes of stimulation at sub-fusion frequencies suggest that no such independence holds for computation of luminous flux over time.     

Visual search through short digit sequences is self terminating

Subjects searched through 2, 4, 6, and 8 digit arrays for a target digit, which, when present, was half the time represented once, and half the time twice in the array. Search latencies were shorter under the dual than the single target condition, supporting a self terminating model of search through these displays.     

Inner speech and the inner life

The pathophysiology of developmental or acquired stuttering still remains an enigma. In a few cases, the developmental stuttering that had disappeared spontaneously or as a result of therapy reoccurred following a brain lesion. We report on a patient with return of developmental stuttering following a left hemispheric stroke. This case supports the theory that acquired brain lesions may cause a return of stuttering, possibly by interfering with the compensatory mechanism(s) that once had relieved the developmental stuttering.