Recognition memory performance as a function of reported subjective awareness

Three experiments introduced a recognition memory paradigm designed to investigate reported subjective awareness during retrieval. At study, in Experiments 1A and 2, words were either generated or read (generation), while modality of presentation (auditory versus visual) was manipulated in Experiment 1B. Word pairs (old/new or new/new) were presented during test trials, and participants indicated if they contained an old word by responding "remember", "know" or "new" in Experiments 1A and 1B, and by responding "strong no", "weak no", "weak yes", or "strong yes" in Experiment 2. Participants were then required to decide which of the 2 words was old. We demonstrated that the proportion measures used in the Remember Know paradigm substantially underestimated the influence of generation on familiarity resulting in an artificial dissociation between indices of knowing (familiarity) and remembering (recollection). We also found a qualitatively different pattern of forced-choice recognition performance as a function of claimed awareness.     

Perceived velocity as a function of reference mark density

The effect on apparent visual speed of varying the density of stationary reference marks evenly distributed along the path of motion of a point of light was measured using tactile comparison motion. The sensitivity of the tactile method of measuring visual speed was supported by the finding that the tactile measures increased with each increase in physical speed of the point of light, other factors held constant. This procedure was applied in two experiments to visual displays in which the physical speed, extent of motion, and number and density of reference marks was varied. Only reference mark density, in addition to physical speed, was found to be a signficant (and robust) factor in determining perceived speed. The effect of reference mark density is explained in terms of the increasing contribution of relative motion cues to the perception of visual speed as a funciton of the average separation (or average adjacency) of the moving point from surrounding reference marks.     

Distance perception as a function of photographic area of view

Distance perception of depicted objects was examined as a function of photographic area of view. Subjects viewed slides of natural outdoor scenes and directly estimated the distances to specified objects. Area of view was manipulated by means of photographing each scene with lenses of five different focal lengths: 135, 80, 48, 28, and 17 mm. Distance perception along the pictorial depth plane was systematically transformed through changing the photographic area of view: the shorter the focal length of the camera lens, the wider the area of view, and the greater the perceived distance. Linear functions for each subject's distance judgments revealed a very high goodness of fit. Both the y-intercepts and the slopes increased as focal length decreased. The increasing y-intercepts suggest that viewers place themselves farther away from the depicted scene as focal length decreases, compensating for the advancing proximal edge. The increasing slopes suggest that distance information throughout the pictorial depth plane appears to change with focal length. The subjects also made direct judgments of foreground truncation, revealing that foreground truncation decreased as focal length decreased, but that this decrease did not account for the considerable expansion in distance perception.     

A case of a dual frame of reference.

It is demonstrated that observers may relate to two parts of the same object by using two different frames of reference. Subjects were asked to indicate directions within a model of a hallway in which signs were posted on a single prism. The majority of subjects interpreted a sign frontally facing them as indicating the direction which is ahead of them, yet they interpreted an adjacent sign that was slanted with respect to the frontal plane as indicating a direction which is at the same side of the line of sight as the sign is. This manifests a mixture of an egocentric and an object-centred frame of reference, that is reminiscent of the mixture of local spatial interpretations in impossible pictures. It is suggested that frames of reference are not necessarily unique in a given percept, and that they are not derived from a global computation.     

Age differences in target identification as a function of retinal location and noise level: examination of the useful field of view

Foveal and peripheral target detection were compared in young adults (M age = 22 years) and older adults (M age = 66 years) who were optically corrected for the viewing distance. In a two-alternative, forced-choice task, target letters were presented at 0 degree to 10.5 degrees from fixation. Targets were presented alone, flanked on each side by one noise element (i.e., nontarget letter), or embedded in a horizontal row of 19 noise elements. An Age X Noise Level X Location interaction was obtained, wherein age differences were largest for peripheral targets presented in noise. Slope analyses of latency data showed that the performance of young adults in the high-noise condition was most similar to that of older adults in the low-noise condition. At the functional level, results indicated that aging is associated with a restricted useful field of view. In addition, the data suggest that age differences in search can be described by a model in which older adults take smaller perceptual samples from the visual scene and scan these samples more slowly than do the young adults.     

Illusion magnitude as a function of visual field exposure

Forty-eight right-handed subjects divided into four groups, each consisting of six males and six females, were employed in an investigation of cerebral hemispheric influence on the perception of tachistoscopically presented simultaneous and successive versions of the Mueller-Lyer figure. The simultaneous version exposed in the left visual field resulted in a larger effect than did right visual field exposures. The successive version exposed in the right visual field resulted in a larger illusion magnitude than it did in the left visual field. The magnitude of visual field differences in response to the successive version was greater than visual field differences found in response to the simultaneous version     

The rod and frame effect and induced head tilt as a function of observation distance

Several experiments investigated the influence of a tilted luminous frame on the rod and frame effect (RFE) and on adjustments of the head to apparent vertical, while observation distance to the frame was varied between 1 and 5 m. Comparisons of repeated measures from the same subjects as well as between independent groups showed that distance was a highly effective variable. Both the RFE and the apparent head tilt varied inversely with distance to the frame, diminishing Lo zero at about 5 m. Since head settings were in the direction of the tilted frame, the latter may be inferred to have caused an induced head tilt (IHT) opposite in direction to the tilted frame, when the head was objectively upright. Issues discussed were the role of IHT in the RFE and factors underlying the role of distance in both phenomena.     

Long-term perceptual memory for briefly exposed words as a function of awareness and attention.

Two experiments investigated the possibility that perceptual memory for words is dependent on level of awareness of those words. In Experiment 1, subjects attempted to report briefly exposed words in a study phase and then identify words that faded into view in a test phase. Old words appeared in both the study and test phases, whereas new words appeared only in the test phase. Perceptual memory, indexed as the faster identification of old vs. new words, was observed only for words correctly reported in the study phase. In the study phase of Experiment 2, words were flanked by digits, and the distribution of attention between words and digits was varied. Perceptual memory increased from nil to high levels as more attention was allocated to the words. These findings suggest that long-term perceptual memory is dependent on level of awareness of words in the study phase.