Effect of distance instructions on size judgments

The proposition that in a reduced-cue setting subjects could use cognitive information about an object's distance to make accurate judgments of its size was tested. An improved paradigm was used to determine the effects of distance instructions per se. This paradigm also allowed independent tests of the effectiveness of cue reduction. The data indicated that cue reduction was successful and that the specific distance tendency governed size judgments when there were no distance instructions. When distance instructions were given, they produced size judgments in precisely the ratio predicted by the size-distance invariance hypothesis. However, there was a large constant error, which reflects a tendency of college students to overestimate the amount of distance signified by a verbal instruction. Hence, cognitive information in the form of verbal distance instructions has precise effects on size judgments, but the latter are not veridical, even in the absence of anchor effects from the specific distance tendency and residual perceptual cues.     

Quantitative functions for size and distance judgments

A psychophysical approach was used to obtain judgments of visual extent under three conditions. In tuvo conditions a comparison stimulus at each of two distances was matched in size to a standard which varied in distance. Stimuli were presented on a well-lighted table and were judged by two observers under Objective instructions. Both the standard and comparison were located in either a frontal or longitudinal plane. In a third condition relative distance estimates were given of two stimuli which varied in their relative positions along the table. The mean results for all conditions were described as a power function of physical stimulus measures. The exponent was greater than 1.0 for frontal size and usually less than 1.0 for flat size and distance. The position of the comparison affected the magnitude of the exponents to a lesser degree. These findings have relevance for interpretations of size and distance judgments.     

The effects of familiar size on judgments of size and distance: An interaction of viewing attitude with spatial cues

Two hypotheses about the effects of familiar size on judgments of size and distance, the cue-conflict hypothesis and the viewing-attitude hypothesis, were examined. In Experiment 1, observers estimated the size and distance of familiar targets with apparent or assumptive instructions under three different spatial cue conditions. In Experiment 2, observers performed tasks similar to those of Experiment 1 with no specific instructions. The main results were: (1) Assumptive instructions facilitate the effects of familiar size in both size and distance judgments, but reducing spatial cues does not, and (2) viewing attitude changes from the apparent to the assumptive when available spatial cues are reduced. Thus, it was concluded that the viewing-attitude hypothesis gives a better account of the effects of familiar size, but that the cue-conflict hypothesis cannot be abandoned, because the number of conflicting cues contributes to the formation of viewing attitude.     

The role of instructions and familiar size in absolute judgments of size and distance

The effects of familiar size and instructions (apparent, objective) on direct reports of size and distance were evaluated. Subjects estimated the size and distance of two different-sized playing cards or two unfamiliar stimuli under either apparent or objective instructions. The stimuli were presented successively at a distance of 5.48 m under reduced-cue conditions. The form of the instructions selectively influenced the effect of familiar size on absolute judgments of size and distance, with apparent instructions minimizing, and objective instructions promoting, familiar-size effects. The ratio of the distance judgments of the first to the second presented stimuli approximated the relative retinal sizes of the two objects under both apparent and objective instructions, while the ratio of size judgments tended to be either influenced by or independent of the object’s relative retinal sizes under apparent and objective instructions, respectively. These results are consistent with Gogel’s theory of off-size perception and, in particular, with the claim that, in comparison with apparent instructions, objective instructions are more likely to direct observers to base their judgments on cognitive, as opposed to perceptual, sources of spatial information.     

The time it takes to make veridical size and distance judgments

Two experiments measuring the time it takes to make veridical size judgments under normal (unreduced) conditions of viewing showed that RT tended to increase with increases in viewing distance between 122 and 305 cm, even for targets subtending the same visual angle at all distances. Two experiments measuring the time it takes to judge distance under the same conditions did not reveal any difference in RT as a function of the extent-of-distance judged. Established accounts of size perception do not suggest an explanation of these findings.     

The role of instructions and familiar size in absolute judgments of size and distance.

The effects of familiar size and instructions (apparent, objective) on direct reports of size and distance were evaluated. Subjects estimated the size and distance of two different-sized playing cards or two unfamiliar stimuli under either apparent or objective instructions. The stimuli were presented successively at a distance of 5.48 m under reduced-cue conditions. The form of the instructions selectively influenced the effect of familiar size on absolute judgments of size and distance, with apparent instructions minimizing, and objective instructions promoting, familiar-size effects. The ratio of the distance judgments of the first to the second presented stimuli approximated the relative retinal sizes of the two objects under both apparent and objective instructions, while the ratio of size judgments tended to be either influenced by or independent of the object's relative retinal sizes under apparent and objective instructions, respectively. These results are consistent with Gogel's theory of off-size perception and, in particular, with the claim that, in comparison with apparent instructions, objective instructions are more likely to direct observers to base their judgments on cognitive, as opposed to perceptual, sources of spatial information.     

The effect of verbal size information upon visual judgments of absolute distance

When an 0 views a blank triangle of light under completely reduced conditions, he is able to make use of verbally conveyed information about the size of this stimulus when he is attempting to judge the absolute distance of the stimulus. Although between-Os variance is rather large in this situation, group mean distance estimates are highly veridical. This is further evidence for the view that, when the 0 is given a retinal subtense, any kind of information about size enables him to make a judgment of absolute distance, just as information about distance enables him to make a judgment of absolute size.     

The influence of haptic size information upon visual judgments of absolute distance

When O views a blank triangle of light under completely reduced conditions, he is able to use information about the size of this visual stimulus conveyed via the haptic modality when he is attempting to judge the absolute distance of the visual stimulus. However, distance is consistently underesti-mated in this situation. When haptically-indicated size is held constant, judged distance varies inversely with retinalsubtense, even though the different retinal subtenses are viewed by different Os. A variant of the size-distance invariance hypothesis also appears to hold in these circumstances.     

Symbolic distance and congruity effects for paired-comparisons judgments of degree of self-reference

Two experiments are reported which speak to the properties of the process of self-reference. The first demonstrated a “symbolic distance effect” for self-reference. An inverse linear relation was found between item difference on a self-referent continuum and the time required to judge which of a pair of adjectives best described the respondent. The second experiment failed to demonstrate a “congruity effect” in a situation where subjects decided which of a pair of adjectives BEST or LEAST described them. This failure was interpreted as support for the proposition that the self functions as an immovable, rigid, and fixed reference point during the processing of personal information. Discussion focused upon how this fixed reference point property helps understand some other research findings.     

Two types of phenomenal instructions for size and distance judgments of objects presented on a two-dimensional plane

Demand characteristics were studied in a simple situation in which observers made size and distance estimates of stimuli presented on a two-dimensional linear perspective drawing. Half the Ss were asked questions stressing phenomenal report: The other half were asked the same questions preceded by instructions stressing the objective nature of the stimulus configuration but requesting, nonetheless, phenomenal report. Instructions resulted in a significantly greater perspective size illusion but did not affect the distance estimates. No meaningful correlations between size and distance estimates were found.     

The effects of perspective alterations on apparent size and distance scales

Ss made magnitude estimations first of the areas, then of the distances, of four circles presented at five distances within an enclosed box 9 ft long. There were three viewing situations: the box had parallel walls, converging walls, or diverging walls. The variations in perspective cues influenced the apparent distance scales: with converging and parallel walls, apparent distance grew as the 1.4 power of physical distance; with diverging walls, it grew as the .95 power. Apparent area was related to distance differently in the three conditions: with converging walls, apparent area increased with distance; with parallel and diverging walls, apparent area decreased with distance. Apparent area was thus not related to changes in physical distance as the apparent distance effects would predict. In each condition, the ratio of apparent area to apparent distance (S′/D′) was a monotonie increasing function of retinal angle θ, but the rate of growth varied among the three conditions. The failure of θ D′ to define a unique value of S′ across conditions indicates that the size-distance invariance hypothesis is inadequate to predict the outcome of this experiment.     

Salience and asymmetric judgments of physical distance

Previous research has shown that distance estimates made from memory are often asymmetric. Specifically, when A is a prominent location (a landmark) and B is not, people tend to recall a longer distance from A to B than from B to A. Results of two experiments showed that asymmetric judgments of distance are not restricted to judgments made from memory but occur also for judgments made when all relevant visual cues are still present. Furthermore, results indicated that situational salience is sufficient to produce asymmetric judgments and that distinctiveness (such as in the case of architectural landmarks) is not necessary.     

Psychological distance and judgments of causal impact

When assessing causal impact, individuals have to consider two pieces of information: the magnitude of the cause that resulted in an effect, and the magnitude of the resulting effect. In the present research, participants judged the causal impact of cause–effect relationships in which the magnitude of causes and effects varied independently. Participants mainly relied on effect magnitude, rating causal impact to be much higher when strong (vs. weak) effects emerged. When participants took cause magnitude into account (which they did, but to a lesser extent), their judgments reflected a covariation rule (i.e., causal impact being maximal for strong causes generating strong effects) rather than a ratio rule (i.e., causal impact being maximal for weak causes generating strong effects). These distinct views on causal impact were moderated by psychological distance: Effect magnitude dominated judgments of proximal events, whereas cause magnitude had relatively more impact on causal judgments of distal events.