Parallel discrimination of subjective contours defined by offset gratings

Recent physiological studies (von der Heydt & Peterhans, 1989) suggest that the orientation of subjective contours is encoded very early in the visual system (V2 in monkey). This result is seemingly at odds with existing psychophysical data which suggest that the detection of subjective contours involves selective attention. It is argued that certain subjective contours are registered in a reflexive (bottom-up) manner by the visual system but that selective attention may be needed to gain access to this representation. To assess this suggestion, a visual-search task was used in which subjects were to detect the presence of a horizontal (vertical) subjective contour (defined by offset gratings) in a variable number of vertical (horizontal) subjective contours (also defined by offset gratings). When there were no competing organizations within the display, detection was indeed independent of the number of nontarget distractors, that is, selective attention was unnecessary. In a second experiment, we found that a curved form (a crescent defined by subjective contours) was easier to detect in a background of vertical bars (also defined by subjective contours) than vice versa, namely, a search asymmetry paralleling those found by Treisman and Gormican (1988). A final experiment showed that when the horizontal and vertical bars of the first experiment formed textured regions, they could be discriminated at very brief display durations (30–120 msec), However, when the line terminations aligned along the subjective contour were tapered rather than abrupt, discrimination dropped off with the degree of tapering. The latter result is consistent with the assumption that the registration of subjective contours in V2 involves the integration of responses from aligned, end-stopped cells found in VI (von der Heydt & Peterhans, 1989).     

Trading relations in the perception of speech by 5-year-old children

Five-year-old children were tested for perceptual trading relations between a temporal cue (silence duration) and a spectral cue (F₁ onset frequency) for the “say-stay” distinction. Identification functions were obtained for two synthetic “say-stay” continua, each containing systematic variations in the amount of silence following the /s/ noise. In one continuum, the vocalic portion had a lower F₁ onset than in the other continuum. Children showed a smaller trading relation than has been found with adults. They did not differ from adults, however, in their perception of an “ay-day” continuum formed by varying F₁ onset frequency only. The results of a discrimination task in which the two acoustic cues were made to “cooperate” or “conflict” phonetically supported the notion of perceptual equivalence of the temporal and spectral cues along a single phonetic dimension. The results indicate that young children, like adults, perceptually integrate multiple cues to a speech contrast in a phonetically relevant manner, but that they may not give the same perceptual weights to the various cues as do adults.     

Digital daydreaming: Introducing the spontaneous smartphone checking scale

Smartphones are a ubiquitous part of many people's lives, but little is known about their impact on everyday thought processes. Here we introduce the spontaneous smartphone checking scale (SSCS)—which measures the tendency to direct attention toward one's smartphone, unpreceded by external prompts (e.g., notifications, or alerts) and with no specific conscious goal in mind, as a parallel to mind-wandering directed toward internal thoughts. The SSCS showed good psychometric properties and construct validity. It separated from measures of daydreaming and mind-wandering by not loading on dimensions related to self-consciousness, reflection, and rumination, but instead loading highly on a factor associated with other aspects of digital communication and concerns about public appearance on social media. This suggests that spontaneous smartphone checking serves different mental and social functions than internally generated spontaneous thought processes. We discuss possible long-term effects of spontaneous smartphone checking taking up time for internally generated spontaneous thoughts.     

“Center-of-gravity” Tendencies for fixations and flow patterns

Fixation positions were measured for a variety of simple patterns. Generally, the spontaneous fixation tendencies hovered near the “center-of-gravity” of the pattern, providing that the overall dimensions of the figure were less than about 5 deg. “Open” figures such as angles were found to be roughly equivalent to their “enclosed” counterparts, such as triangles. The constraints imposed by the pattern upon the fixation tendencies occur at a level where the binocular inputs are processed. Of further importance was the fact that the fixation points approximate the foci observed in the same patterns when they are seen against a background of visual noise. It is suggested that the two results may be functionally related..     

Stereopsis with opposite contrast contours

The effects of incidental stimuli, defined as visual stimuli not under verbal control, upon a selection task were observed as a function of feedback contingency. Ss judged letter pairs to be valid or invalid completions of preceding letter parts. During the presentation of the letter parts, the response pair or an alternative pair of letters was intermittently presented at a threshold value individually determined for each S. One group of Ss received a light feedback of performance contingent upon responding to the incidental stimuli; whereas a second group received a random noncontingent feedback. The results indicated: (a) both groups responded to the incidental stimuli; (b) feedback contingency had no effect on frequency of responding to the incidental stimuli; (c) frequency of responding to the incidental stimuli remained constant over 32 trials.     

The effects of coding procedure on human information transmission

Three different coding schemes, i.e., transformations between stimuli and responses, were used in a continuous information transmission situation. The stimuli were groups of binary digits and S was required to transform these into verbal equivalents of combinations formed by taking various sets of the English letters. Three codes, one based on communication theory, one based on Miller’s (1956) chunking hypothesis, and a combination of the first two were used. In addition, two levels of stimulus redundancy, zero and 0.5 were used. Time to complete the task and errors were the de-pendent variables. The Ss were run for twelve days. The basic result was that Ss transmitted information at a constant rate regardless of the code or redundancy level used.     

Information and the memory span

Messages differing in number of symbols and symbol information load were presented tachistoscopically to 4 adult Ss. The messages were constructed by random drawing with replacement from an alphabet of 8 black form symbols and an alphabet of 32 colored form symbols. The number of symbols recalled varied as a function of alphabet; however, the information in recall was constant for all conditions. The number of symbols recalled and the information in recall was independent of message length.     

Children's judgments of body size and distortion

Body size estimates of 69 children aged 5–13 years were obtained using a TV video methodology. Tasks included an adjustment procedure where children manipulated the width of their body image on a TV, and a discrete task, where they judged the accuracy of their TV image which was presented as either normal or distorted, that is, too wide or too thin. On the continuous task, judgments were more accurate on ascending trials where children had to increase the width of the image. On the discrete task, a signal detection analysis revealed older children were better in detecting size distortion in their images and that the differences were due to differences in the biological sensory system and not due to a bias to report that they were too fat or too thin. However, there were response bias differences between genders. Females were more likely to report size distortion with increasing age while males were less likely.     

Small Wins: Perceptual Focus,Efficacy, and Cooperation in a Stage-Conjunctive Social Dilemma1

A multi-stage social dilemma was used to explore the notion that focusing on part rather than all of a complex problem would affect self-efficacy and action. In two experiments subjects considered a multi-stage game asking them to invest an initial sum of money in hopes of earning a larger bonus to be paid if provision points were met at all stages (a “stage-conjunctive” task). Results indicated that under most conditions considered, presentation of the whole problem encouraged cooperation. The opposite pattern occurred when group members were asked to complete very demanding stages first. We suggest that these results depend strongly on the stage-conjunctive nature of our task.