Language performance on visual processing tasks in right hemisphere lesion cases

Seven language tests were constructed or adapted to assess the performance of three groups of 10 right-handed adult subjects: a right hemisphere lesion (RHL) group, a left hemisphere lesion (LHL) group, and a neurologically normal (NN) control group. Both the LHL and RHL groups produced poorer scores than the NN group on six of the seven tests. On two of the six significant tests, the RHL performed more poorly than the NN group. Analyses of words uttered during an oral story telling test indicated that the RHL group told significantly fewer complete stories using significantly more nouns, adjectives, and conjunctions than the NN group. On a 7-point scale, three judges rated the overall communication abilities of the RHL group as having “mild problems,” a significantly different rating than the ratings of the LHL and NN groups. The findings suggest that underlying visual spatial and perceptual deficits may be accompanied by clearly recognizable language differences in certain subjects.     

When does perceived lightness depend on perceived spatial arrangement?

Experiments have recently been reported in which a decisive change in perceived lightness was produced by a change in perceived spatial position, with no important change in the retinal image. A number of previous studies had found little or no such effect. Experiments of the kind that produced these effects and of the kind that do not produce these effects are presented here. The main differences between these two kinds of experiments are discussed. One difference is whether the display allows the target to be part of one ratio in one spatial position but another in the other spatial position. Another difference concerns the range of luminances within the display. Also discussed are the implications of these findings for cognitive vs. S-R theories, the order of processing depth and lightness, laboratory data vs. experience, the role of lateral inhibition in lightness perception, and theories of lightness perception in general.     

A simple inexpensive computer-controlled tone generator

A simple circuit for a keyed tone generator is described. The total construction cost is less than $5. Various adaptations and modifications of the circuit are discussed.     

Binocular interaction of orientation and spatial frequency channels: Evoked potentials and observer sensitivity

The interaction between size and orientation feature processing in the human visual system was investigated. Both observer sensitivity (d’ss) and the visual evoked potential (VEP) to test gratings flashed to one eye were investigated as a function of the nature of a continuously presented suppressing grating viewed either by that same eye or the opposite eye. The test and suppressing gratings were varied both in bar width (9′ss vs. 36′ss) and orientation (vertical vs. horizontal). The continuous grating intra- and interocularly suppressed the monocular VEPs to the flashed grating, the specificity of the suppression depending on the latency at which VEP amplitude was measured. VEP amplitude measured at early latencies (100–125 msec) was suppressed primarily when the flashed and continuous gratings were the same orientation, regardless of size. Starting at about 200 msec, and thereafter, VEP amplitudes were suppressed when the continuous bars were either the same orientationor size as the flashed bars. Late latencies, starting at 220 msec, and thereafter, were suppressed primarily when the bars in the two gratings were the same orientation and size. The reduction in observer sensitivity (d′ss) paralleled the changes found in the late VEP measures. These effects were evident under both the intraocular and interocular suppressing conditions. This pattern of VEP suppression, measured across eight points in the VEP waveform, was interpreted as indicating the existence of a sequence of channels that are specific first to a particular grating orientation, then to either a particular grating spatial frequency or orientation, and finally to the conjunction of a particular orientation and spatial frequency. Both sequential and parallel feature processing appears to take place in the human visual cortex, with grating orientation being encoded earlier than grating size.     

The role of some spatial parameters of gratings on the McCollough effect

Ss were alternately adapted to vertical and horizontal gratings that consisted of black bars and colored slits. The slits of one grating were green and of the other, magenta. The widths of the black bars and the colored slits were varied independently during adaptation and testing. This design separates the relative influence of bar width, slit width, and spatial frequency on an orientation specific color aftereffect known as the McCollough effect. Black bar width had the major influence on the strength of the aftereffect, suggesting that the neurophysiological mechanism underlying the McCullough effect might consist of orientation specific units that are sensitive to both the widths of black bars and the chromatic characteristics of their surrounds.     

Spatial effectiveness of the mask: Lateral inhibition in visual backward masking

Introducing a figure into a masking flash results in visual backward masking under conditions where a homogeneous masking flash does not suppress target detection. It is possible to analyze the spatial effects of such a masking figure in terms of lateral inhibition. It is hypothesized that incorporating a figure into the masking flash changes the inhibitory pattern the mask produces in the visual system. The interaction between the firing pattern produced by the mask and the residual inhibition from the preceding target presentation results in a phenomenal representation different from that produced by either the target or the mask alone.     

Book reviews

Timing in Temporal Tracking. By J. A. Michon. Soesterberg, Netherlands: Institute for Perception RVO-TNO, Netherlands. 1967. Pp. 127.

Human Performance. By Paul M. Fitts and Michael I. Posner. Belmont, California: Brook/Cole Publishing Co. 1967. Pp. x + 162. 14s.

Human Memory. By Jack A. Adams. New York: Mcgraw Hill. I967. Pp. ix + 326. $9.50.

Biological Foundations of Language. By Eric H. Lenneberg. With Appendices by Noam Chomsky and Otto Marx. New York and London: Wiley. 1967. Pp. xvi+489. £6.

The Genesis of Language: A Psycholinguistic Approach. Edited by Frank Smith and G. A. Miller. Cambridge, Massachusetts and London: The M. I. T. Press. Pp. xii + 400. $4.

Acquisition du Langage at Developpement de la Pensee. By H. Sinclair-de Zwart. Paris: Dound. 1967. Pp. vi+ 168. 23F.

Principles and Methods of Social Psychology. By E. P. Hollander. London and New York: Oxford University Press. 1967. Pp. xxiii + 520. 64s.

Current Perspectives in Social Psychology. Second Edition. Edited by E. P. Hollander and R. G. Hunt. London and New York: Oxford University Press. 1967. Pp. vii + 685. 40s. (paper).

The Use of Lateral Thinking. By Edward de Bono. London: Cape. 1967. Pp. 157. 18s.

“Instinct” and “Intelligence”: The Science of Behaviour in Animals and Man. By S. A. Barnett. London: Macgibbon & Kee. 1967. Pp. xiv + 250. 45s.     

Conditional permission in deontic logic

Conclusion In the face of the considerations set forth above, I submit that Anderson's proposed definition (D) does not represent an acceptable construction of the concept of conditional permission. This, in turn, suggests that conditional permission must be viewed as a viable deontic relationship in its own right, and is not definable in terms of unconditional deontic concepts. It appears, then, that a reduction of conditional to unconditional deontic logic is not warranted.