Angry men and happy women – A pre-registered replication using psychophysics

Judgments about the emotional expression of a face are influenced by its sexual features, and vice versa. The cause of this interaction remains unclear. Most previous research has used standard analyses of categorisation responses to full-blown emotional expressions. A better understanding of the phenomenon may however require the adoption of nuanced stimuli and sophisticated analyses methods. For example, Harris et al. (2016), used psychophysics methods to compare responses to faces displaying emotions at several intensity levels. The point of subjective equality (PSE), at which happy and angry categories are equally likely, was found to be closer to the happiness pole for male compared to female faces. Because these methods seem promising for the quest of advancing the field to a better understanding of how emotional and social judgments of faces are formed, we attempted a replication of Harris et al.’s study, after pre-registration in an independent public registry (https://bit.ly/2v8BW7Q). A large sample (N = 108) from a comparable population was tested with the same stimuli and task as in the original publication. We successfully replicated the main and some secondary findings, which we discuss in the context of the literature, and we indicate promising avenues of research in this domain.

Encoding-Stage Adaptation Effects: Long-Term Memory

Given adaptation changes perceptual experience, it probably shapes long-term memory (LTM). Across four experiments, participants were adapted to strongly gendered (male, female: Experiments 1 and 2) or aged faces (old, young: Experiments 3 and 4) before LTM encoding and later completed an LTM test in which the encoded faces were morphed with the opposite end of the relevant continuum. At retrieval, participants judged whether probe faces were more or less male or female or young or old than when presented during encoding. For male, female, and young faces, encoding-stage adaptation significantly shifted the point of subjective equality in the unadapted direction. Additionally, encoding-stage adaptation significantly enhanced recognition of faces during LTM retrieval. We conclude that encoding-related adaptation is reflected in LTM.

Perception of combined translation and rotation in the horizontal plane in humans

Thresholds and biases of human motion perception were determined for yaw rotation and sway (left-right) and surge (fore-aft) translation, independently and in combination. Stimuli were 1 Hz sinusoid in acceleration with a peak velocity of 14°/s or cm/s. Test stimuli were adjusted based on prior responses, whereas the distracting stimulus was constant. Seventeen human subjects between the ages of 20 and 83 completed the experiments and were divided into 2 groups: younger and older than 50. Both sway and surge translation thresholds significantly increased when combined with yaw rotation. Rotation thresholds were not significantly increased by the presence of translation. The presence of a yaw distractor significantly biased perception of sway translation, such that during 14°/s leftward rotation, the point of subjective equality (PSE) occurred with sway of 3.2 ± 0.7 (mean ± SE) cm/s to the right. Likewise, during 14°/s rightward motion, the PSE was with sway of 2.9 ± 0.7 cm/s to the left. A sway distractor did not bias rotation perception. When subjects were asked to report the direction of translation while varying the axis of yaw rotation, the PSE at which translation was equally likely to be perceived in either direction was 29 ± 11 cm anterior to the midline. These results demonstrated that rotation biased translation perception, such that it is minimized when rotating about an axis anterior to the head. Since the combination of translation and rotation during ambulation is consistent with an axis anterior to the head, this may reflect a mechanism by which movements outside the pattern that occurs during ambulation are perceived.

The categorical perception of tactile distance: A difference in acuity at anatomical landmarks?

Tactile distance judgments are prone to a number of physiological and perceptual distortions. One such distortion concerns tactile distances over the wrist being perceptually elongated relative to those within the hand or arm. This has been interpreted as a categorical segmentation effect: The wrist implicitly serves as a partition between two body part categories so that stimuli crossing the wrist appear further apart. The effect could alternatively be explained in terms of specialized acuity at anatomical landmarks (i.e., the wrist). To test these opposing explanations we presented participants with two tactile distances sequentially for comparison (one mediolaterally, across the arm, and the other proximodistally, along the arm). Points-of-Subjective-Equality (DV) were compared on the hand, wrist and arm, on dorsal and ventral surfaces between subjects. If the acuity account were true distances would be elongated in both axes at the wrist. If the categorical segmentation account were true there would be a selective perceived increase of the proximodistal distance at the wrist. A previously reported mediolateral bias was found on all body parts but, consistent with the categorical account, at the wrist the magnitude of the bias was either reduced (dorsally) or not found (ventrally) suggesting a selective proximodistal elongation. We found no evidence of increased acuity in the vicinity of the wrist in this task. Therefore we conclude that the segmentation of the body into discrete parts induces categorical perception of tactile distance.

Bilateral Assimilation of Two Neighboring Empty Time Intervals

In many sensory dimensions, assimilation of characteristics of perceived events can be found. In the present study, we examined whether assimilation appeared also in time perception, employing time intervals shorter than 300 ms marked by tone bursts. In Experiment 1, we measured points of subjective equality of two neighboring empty time intervals, t1 and t2. The perceived durations approached each other when the difference between t1 and t2 was small. That is, bilateral assimilation took place. In Experiment 2, we measured points of subjective equality of t1 in smaller steps and across a wider durational range than in Experiment 1. We found that t1 was overestimated slightly when it was a bit shorter than t2, and t1 was underestimated slightly when it was a bit longer than t2. The overestimation and the underestimation were considered as typical assimilation. The results also showed that the perception of t1 changed from assimilation to contrast when the difference between t1 and t2 exceeded the range -80 � t1 � t2 � 40 ms.