Lior Cohen-Raz

Visual velocity input-output functions: The integration of distance and duration onto subjective velocity

Subjects made magnitude estimations of moving stimuli produced by a 10 X 10 factorial design of distances and durations. Both group and individual data obeyed the bilinear interaction prediction of a simple ratio model. The relation between perceived and actual velocity, as well as the psychophysical contingencies constructed from the marginal means of the design, could be described by a power function with an exponent of about 0.63 as a representative figure. Plotting subjective velocity against physical velocity with either duration or distance as the parameter resulted, respectively, in families of converging psychophysical power functions. Some implications of the results for velocity research, especially the usefulness of specifying the correct metric structure, are discussed.

Integration of noxious stimulation across separate somatosensory communications systems: a functional theory of pain

Functional measurement analyses and psychophysical techniques were used to assess how separate, cross-modal, aversive events are integrated in judgements of pain. Subjects made magnitude estimations of noxious stimuli produced by a 6 X 6 factorial design of electric shocks and loud tones. Group data and most of the individual results were consistent with a model of linear pain summation: The estimates of pain approximated the linear sum of the pain estimates of the individual electrocutaneous and auditory components. The relation between painful sensation and current intensity could be described by a mildly expansive power function with an exponent of about 1.1. Auditorily produced painful sensation related to sound pressure level by a mildly compressive power function with an exponent of about 0.90 as a representative figure. Results are interpreted in terms of a functional theory of pain. Noxious events are first transformed to psychological scale values via stimulus-specific psychophysical transfer functions. The outputs of these functions are then combined with other pain-related internal representations of either sensory or cognitive origin, according to simple algebraic models.

Sensory and Cognitive Factors in the Processing of Visual Velocity

A symmetrical 6 x 6 factorial design of distances and durations served to produce either 36 different moving stimuli (real movement condition) or 36 static displays separately containing the respective stimulus components (cognitive movement condition). Different metric rules underlay the two types of velocity judgments: Perceptual estimations of real movement obeyed a ratio model, whereas conscious estimations of implied movement obeyed an additive model. Valuation operations differed, too; the scales underlying real velocity were nonlinearly related to the even more compressive scales that underlay cognitive velocity. Implications of these results for velocity research are discussed.

Binaural summation and lateralization of transients: A combined analysis

Subjects judged the loudness and the lateral position of dichotic transient signals, which were presented at equal and unequal levels, synchronously and asynchronously, to the two ears. Binaural loudness summation of clicks does not obey a law of linear addition: It is partial at low level and superadditive at high level. Supersummation is greater for interaurally delayed clicks than for coincidental ones. The relation between click loudness and sound pressure (over moderate SLs) can be described as a power function with a greater exponent for the binaural function. Lateral positions spread over a greater range for interaural level differences than for interaural time differences. The time-intensity trading ratio was greater than is typically reported for tones. When sound lateralization was induced by interaural time difference, but not by intensity difference, a virtually perfect negative correlation between loudness and extent of off-center displacement existed.

Binaural and temporal integration of the loudness of tones and noises

Subjects judged the loudness of tones (Experiment 1) and of bursts of noise (Experiment 2) that varied in intensity and duration as well as in mode of presentation (monaural vs. binaural). Both monaural and binaural loudness, for both types of signals, obeyed the bilinear-interaction prediction of the classic temporal integration model. The loudness of short tones grows as a power function of both intensity and duration with different exponents for the two factors (.2 and .3, respectively). The loudness of wide-band noises grows as a power function of duration (with an exponent of approximately .6) but not of sound pressure. For tones, binaural summation was constant but fell short of full additivity. For noises, summation changed across level and duration. Temporal summation followed the same course for monaural and binaural tonal stimuli but not for noise stimuli. Notwithstanding these differences between tone and noise, we concluded that binaural and temporal summation are independently operating integrative networks within the auditory system. The usefulness of establishing the underlying metric structure for temporal summation is emphasized.

Dichotic, diotic, and monaural summation of loudness: A comprehensive analysis of composition and psychophysical functions

In a series of six experiments, the method of magnitude estimation, constrained by a multivariate model, was used to assess the rules that govern the summation of the loudness of two-tone complexes. This methodology enabled us to specify the amounts of summation and simultaneously to construct the corresponding loudness scales. The components had different frequency separations and in the different experiments were presented (1) dichotically, a different frequency to each ear; (2) diotically, to both ears; and (3) monaurally. Results replicated and in some conditions extended known features of multiple signal processing by the auditory system. Thus, qualitatively different rules of loudness integration appeared. For monaural and diotic modes of stimulation, overall loudness depended on total sound energy within the critical band, but on the simple sum of component loudnesses beyond the critical band. For dichotic presentations, a fully additive rule of loudness summation appeared, regardless of frequency spacing. For the latter (but not the former), loudness summation was perfect, with the underlying loudness scales closely approximating Stevens’s sone scale.

Pain combines additively across different sensory systems: a further support for the functional theory of pain.

Subjects made magnitude estimations of noxious stimuli produced by a 6 × 6 factorial design of electric shocks (pulse trains) and loud tones. Group data and all individual results conformed to a linear additive model of pain. The estimates of pain approximated the linear sum of the pain estimates of the individual electrocutaneous and auditory components. Pain related differently to the two inducing stimuli. It grew as a mildly expansive power function of current intensity (with an exponent of about 1.2) but as a mildly compressive power function of sound-pressure level (with an exponent of about 0.8). These results replicate recent findings by the same authors in 1986 using a more aversive type of electric stimulation. They are interpreted as supportive of a new functional approach to understand pain and pain-related phenomena.

Figure and Ground in the Perception of Crime Severity

Existing group tensions provide a convenient background against which one might both judge the severity of a violent crime and understand the underlying motivation for such an act. By changing the presented context, one should be able to influence the perceived severity of the crime. In the present experiment, 33 Israeli policemen were presented with a series of vignettes describing incidents of an assault with bodily harm. Information included in the incidents was varied systematically according to a 4-way factorial design: Context (Extremist or Criminal), Identity of Assailant (Jew or Arab), Identity of Victim (Jew or Arab), and Degree of Bodily Harm (Low or High). The participants were asked to rate the severity of the assault and of their understanding of the assailants motivation. The findings are discussed in terms of attributional tendencies.

Loudness Scales from Loudness Processes: A Multivariate Approach

Five subjects were required to judge the loudness of pure tones that varied in intensity and duration (Experiment 1), in intensity and frequency (Experiment 2), or in duration and frequency (Experiment 3). Results of all three experiments were consistent with the respective models of sensory integration expected to underlie the various judgmental tasks (multiplicative for the first experiment, unidimensional for the latter two). Despite the use of common stimulus values across experiments and instructions to judge solely loudness, different loudness scales emerged. This outcome supports a task dependent, multirepresentative scheme for loudness.

Perception of Aggression as a Function of Ethnic Affiliation: Moral Judgment of Violence Among Jews and Arabs in Israel

Following previous findings which showed differences between Israeli citizens of Oriental and European descent in regards to moral judgment of aggression, a recent replication studied moral judgment in 358 ordinary Israeli citizens of Oriental (132 Jews and 121 Arabs) and of European (75 Jews) descent. Each participant was individually asked to imagine a series of incidents where a stimulus person inflicted (with little, some, or much intent) physical harm (little, some, or much) on another stimulus person. The participants rated the blameworthiness of the perpetrators behavior in each of the nine incidents included in the complete bi-factorial design (3 × 3). It was found that Israelis of European descent tended to balance the weight of intent and damage while Israelis of Oriental descent from both ethnic-national backgrounds placed a greater emphasis on the damage that occurred. A psycho-sociological conception of the findings is suggested.