When the road is wet (there is a water layer on the road surface), the road marks become blurred and drivers are distracted. We discuss the contributing processes and identify which processes are dominant to the occurrence of this phenomenon. Modelling and a simple experiment demonstrate that the dominant processes are: (a) refraction of light by…

We live in a dynamic environment in which objects change location over time. To maintain stable object representations the visual system must determine how newly sampled information relates to existing object representations, the "correspondence problem". Spatiotemporal information is clearly an important factor that the visual system takes into…

Attention operates to select both spatial locations and perceptual objects. However, the specific mechanism by which attention is oriented to objects is not well understood. We examined the means by which object structure constrains the distribution of spatial attention (i.e., a "grouped array"). Using a modified version of the Egly et…

Historically, the bodily senses have often been regarded as impeccable sources of spatial information and as being the teacher of vision. Here, the authors report that the haptic perception of slope by means of the foot is greatly exaggerated. The exaggeration is present in verbal as well as proprioceptive judgments. It is shown that this…

Describes a perceptual illusion, the Janus mask, for use in introductory psychology demonstrations. Suggests using a motor or videotaped image to rotate the mask, giving the impression that the mask is following a moving observer or oscillating. Recommends the illusion to show that perception is usefully conceptualized as hypothesis testing. (DK)

Discusses human ability to perceive repeated sensory stimuli in the visual system, and explains that its frequency fc has a critical value, under normal conditions, about 40 Hz. (GA)

Describes an experiment in which students work together in small groups, take data, and make a calculation to roughly determine the diameter of the blind spot in their eye. (WRM)

In two experiments we investigated the automatic adjusting of the attentional focus to simple geometric shapes. The participants performed a visual search task with four stimuli (the target and three distractors) presented always around the fixation point, inside an outlined frame not related to the search task. A cue informed the subject only…

Describes an experiment enabling students to apply concept of diffraction, determine limits of their color perception, learn how to measure wavelength with a simple apparatus, observe continuous and line spectra, and associate colors with corresponding wavelengths. The homemade diffraction-grating spectrometer used is easily constructed. (JN)

Provides background theory and an experiment relating to chemometrics. Describes the phenomenon where solutions are dichromatic or dichromic. Discusses the difficulty students have in describing such solutions that appear to be several different colors at the same time. (TW)

The purpose of the study was to determine the effects of rheostatically controlled visual subliminals on the affective interrelations of a learning task of subjects within a classroom setting. Four groups of students were used. Subjects were unknowingly exposed to a rheostatically projected subliminal message for 30 minutes during otherwise normal…

Maintains that having students estimate the size and width of a class waste paper can (placed on a desk) is a simple and effective way of illustrating perceptual distortion. Tests show that people will consistently overestimate the height of the can, allowing for a useful discussion on sensory distortion. (MJP)

A non-informative cue (C) elicits an inhibition of manual reaction time (MRT) to a visual target (T). We report an experiment to examine if the spatial distribution of this inhibitory effect follows Polar or Cartesian coordinate systems. C appeared at one out of 8 isoeccentric (7[degrees]) positions, the C-T angular distances (in polar…