Contextual and sequential effects on judgments of sweetness intensity.

Presenting stimuli from skewed concentration distributions affects mean responses on category scales. However, if the number of categories on the response scale is increased, the degree of separation between the mean responses obtained for a positively as opposed to a negatively skewed concentration distribution diminishes. The present study investigates the effect of skewed concentration distributions upon ratings on a line scale and compares it to the context effect found for a 7-point category scale. In addition, sequential dependencies between consecutive stimuli and responses are investigated in order to assess their relevance in taste-intensity scaling studies. The context effects are similar for the 7-point category scale and for the line scale. The analyses of sequential effects show that both preceding responses and preceding stimuli affect current responses. However, since these two factors work in opposite directions, only a small contrast effect from the previous stimulus is significant in an overall analysis. The present study shows that even though the overall sequential effects between consecutive stimuli and responses are small, the effect of experimental context may be considerable. Since subjective context is established at the beginning of a session and sequential dependencies operate throughout the whole session, it is argued that contextual and sequential effects are only indirectly related.     

Contextual effects in difference judgments

Manipulating stimulus spacing, stimulus frequency, or stimulus range usually affects intensity judgments. In six experiments, I investigated the locus of analogues of these contextual effects in a “difference” estimation task. When all stimuli elicited the same taste quality, stimulus distribution affected the scale values only when water was included in the stimulus set (Experiments 1–3). When the subjective ranges of two taste qualities were manipulated, different scale values were obtained for the separate qualities in the two conditions (Experiment 4). Manipulation of the expected response distribution did not affect the scale values or the responses (Experiments 5–6). It is concluded that shifts in stimulus distributions or stimulus ranges result in shifts in subjective scale values. The contextual effects can be interpreted as relative shifts of a number of gustatory continua, with water lying on a separate continuum. Proposed is a model for context-dependent judgments, consisting of four stages: stimulus classification, stimulus placement, continuum placement, and continuum projection.     

Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Effects of context in judgments of sweetness and pleasantness

Dramatic effects of the immediate stimulus context were demonstrated for ratings of sweetness and also for ratings of pleasantness of soft drinks containing different concentrations of sucrose. The same drinks were rated sweeter when the lower concentrations were presented more frequently, less sweet when the higher concentrations were presented more frequently. A quasi-normal distribution of frequencies yielded ratings falling between the two skewed distributions. Ratings of sweetness were accurately predicted by Parducci’s (1974) range-frequency model of judgment, which was originally developed to explain contextual effects in other psychophysical dimensions. Ratings of pleasantness were also affected by context; the highest ratings were assigned to concentrations of intermediate sweetness in their respective contexts.     

Mood and judgments based on sequential sampling

Different adaptive styles characterize cognition and behavior in different affective states. Whereas negative affect supports accommodation (i.e., stimulus‐driven bottom‐up processing), positive affect supports assimilation (i.e., self‐determined top‐down processing). Applying this well‐established rule to binary choices after self‐truncated information sampling, we predicted that positive mood should render choices less dependent on large samples than negative mood. Consequently, the potential primacy advantage underlying Wald's ( 1947 ) sequential testing (i.e., quick and correct decisions from the first few items in a sample) was exploited more efficiently when participants were in positive rather than negative mood. This efficient utilization of small samples in positive mood was obtained under the very conditions derived on a priori ground from a statistical model, namely, when a response criterion or threshold was high and when the true difference between choice options was relatively small. Copyright © 2009 John Wiley & Sons, Ltd.     

Anchoring in sequential judgments

Building on the scale distortion theory (Frederick & Mochon, 2012), we explore the boundary conditions of anchoring outside of the standard paradigm. We argue that the conditions needed for anchoring effects are much more restrictive than those suggested by some theories, but much less restrictive than those suggested by others. Our findings illuminate both the scope and limits of this well-known effect and provide a framework for predicting its occurrence in novel settings.     

Contextual influences on the sequential congruency effect

The sequential congruency effect (SCE) refers to the reduction in the size of the congruency effect following incongruent, relative to congruent, trials. Prior evidence indicated that the SCE does not generalize across tasks or different conflict-producing feature dimensions. We present results from a Stroop task showing that when the local list context is such that all colors and words appear in the same proportion of congruent trials, the SCE is present, but when those same items vary in the proportions congruent, the SCE is absent. We suggest that if stimuli are sufficiently consistent in the informativeness of their dimensions for the responses, individuals will attempt to track such information and weight the dimensions accordingly. In this way, the SCE reflects sequential adjustments to the weights given to individual stimulus dimensions in an attempt to track this information.     

Contextual judgments of quality of life and adolescent cognitive development

This research explored the relationship between adolescents' level of cognitive reasoning and their contextual judgments of the factors affecting quality of life. In comparison to adolescents at relatively lower levels of cognitive development, it was predicted that those who have achieved higher levels of cognitive reasoning would be: (1) more likely to identify social and interpersonal aspects of life as factors related to quality of life and (2) less likely to identify self issues. Subjects were 443 tenth-grade students from four Michigan school districts. The students were administered the Reasoning Level Test (RLT) and also asked to identify the aspects of their lives that they felt were the most and least satisfying at the moment. A median split was performed and each student was assigned to either a high or low cognitive-level group based upon his/her RLT score. The findings supported the above predictions, but more so in regard to negative than positive factors. The findings are also in line with cognitive-developmental theories of adolescence and indicate that cognitive structures and the specific nature of the factors perceived to influence one's life may mediate contextual judgments of these factors.     

Variability and sequential effects in magnitude production and estimation of auditory intensity

Magnitude production and estimation data from the same subjects are analyzed in three ways. The coefficient of variation of the ratio of successive responses Inumbers in estimation, SPL in production) are compared; both exhibit, as a function of stimulus difference, the V-shaped pattern previously found in estimation data. A multiple regression of responses on the stimulus and on these events of the previous trial exhibit similar patterns, although the effects of the previous trial in production are somewhat less. The correlation between successive responses, averaged over constant stimulus differences, are very large for small differences and about zero for large ones. These somewhat surprisng results for production are examined from the point of view of an intensity attention band hypothesis.     

Contextual effects on number-time interaction

Time perception has long been known to be affected by numerical representations. Recent studies further demonstrate that when participants estimate the duration of Arabic numbers, number magnitude, though task-irrelevant, biases duration judgment to produce underestimation for smaller numbers and overestimation for larger numbers. Such effects were found in the present study to be significantly reduced when a weight unit gram was suffixed to the numbers rendering the mental magnitude differences between different numbers less distinctive. The effects were enhanced when a different unit kilogram was suffixed to the numbers enlarging the perceived magnitude differences between different numbers. The results indicate that effects of number magnitude on duration estimation should not be attributed to the mathematical differences between numbers but to how the numbers are perceived to differ from each other in magnitude in specific contexts when they denote concrete items. The results also provide new evidence for the theoretical proposal of a common generalized magnitude system and indicate that the system must be extended to include other action-oriented magnitudes, such as weight.     

Anchoring effects on performance judgments

Three studies were conducted investigating the effects of irrelevant anchors on performance judgments. Both a lab and field study demonstrated that an alternative anchoring manipulation that did not involve an explicit comparative question had effects on performance judgments similar to a traditional anchoring manipulation. The final study examined whether the anchoring effects were more likely when the anchor was highly applicable to the final judgment. The results indicated that both highly applicable and low applicable anchors produced an anchoring effect, but the highly applicable anchors had a larger effect on performance judgments. Evidence was also found for asymmetrical anchoring effects. In two of the three studies, high anchors increased performance judgments relative to the control group, whereas low anchors were not significantly different from the control group.     

Examining auditory kappa effects through manipulating intensity differences between sequential tones

The auditory kappa effect is a tendency to base the perceived duration of an inter-onset interval (IOI) separating two sequentially presented sounds on the degree of relative pitch distance separating them. Previous research has found that the degree of frequency discrepancy between tones extends the subjective duration of the IOI. In Experiment 1, auditory kappa effects for sound intensity were tested using a three-tone, AXB paradigm (where the intensity of tone X was shifted to be closer to either Tone A or B). Tones closer in intensity level were perceived as occurring closer in time, evidence of an auditory-intensity kappa effect. In Experiments 2 and 3, the auditory motion hypothesis was tested by preceding AXB patterns with null intensity and coherent intensity context sequences, respectively. The auditory motion hypothesis predicts that coherent sequences should enhance the perception of motion and increase the strength of kappa effects. In this study, the presence of context sequences reduced kappa effect strength regardless of the properties of the context tones.     

The effects of viscosity upon perceived sweetness

U.S. Army Natick Laboratories, Natick, Massachusetts 01760 Six concentrations of sucrose and six concentrations of sodium saccharin were presented as stimuli to 30 Ss. The concentrations were equally spaced logarithmically, covering a 32: I range for each solute. The 12 aqueous solutions were presented at four levels of viscosity, ranging approximately from I to 10,000 centipoises, with sodium carboxymethylcellulose (cellulose gum) as the thickening agent. Magnitude estimates indicate that perceived sweetness decreases with viscosity. In log-log coordinates the Viscosity-sweetness relation is roughly linear with a negative slope, suggesting that sweetness of both sodium saccharin and sucrose varies as a power function of viscosity, with an exponent between ?.20 and ?.25.     

Acute exercise suppresses judgments of facial emotion intensity

The ability to recognize others’ facial expressions is critical to the social communication of affective states. The present work examined how transient states of high physiological arousal during aerobic exercise influence recognizing and rating morphed facial expressions. Participants exercised at either a low or high work rate. While exercising and then during cool-down and rest periods, participants performed a version of the morphed faces task that involved animated faces changing into or away from five target affective states (happy, surprise, sadness, anger, and disgust); they were asked to stop the animation when the face first corresponded to a target state, and rate its emotional intensity. Results demonstrated no differences in animation stop data, but overall lower ratings of perceived emotion intensity during high versus low work rate exercise; these effects dissipated through cool-down and rest periods. Results highlight important interactions between physiological states and processing emotional information.