Emotional Semantic Congruency based on stimulus driven comparative judgements

Temporal speed prevails on interval duration in the SNARC-like effect for tempo

The Spatial-Numerical Association of Response Codes (SNARC) effect is evidence of an association between number magnitude and response position, with faster left-key responses to small numbers and faster right-key responses to large numbers. Similarly, recent studies revealed a SNARC-like effect for tempo, defined as the speed of an auditory sequence, with faster left-key responses to slow tempo and faster right-key responses to fast tempo. In order to address some methodological issues of previous studies, in the present study we designed an experiment to investigate the occurrence of a SNARC-like effect for tempo, employing a novel procedure in which only two auditory beats in sequence with a very short interstimulus interval were used. In the "temporal speed" condition, participants were required to judge the temporal speed (slow or fast) of the sequence. In the "interval duration" condition, participants were required to judge the duration of the interval between the two beats (short or long). The results revealed a consistent SNARC-like effect in both conditions, with faster left-hand responses to slow tempo and faster right-hand responses to fast tempo. Interestingly, the consistency of the results across the two conditions indicates that the direction of the SNARC-like effect was influenced by temporal speed even when participants were explicitly required to focus on interval duration. Overall, the current study extends previous findings by employing a new paradigm that addresses potential confounding factors and strengthens evidence for the SNARC-like effect for tempo.

Contrasting symbolic and non-symbolic numerical representations in a joint classification task

Both symbolic (digits) and non-symbolic (dots) numerals are spatially coded, with relatively small numbers being responded faster with a left key and large numbers being responded faster with a right key (spatial-numerical association of response codes [SNARC]). The idea of format independent SNARC seems to support the existence of a common system for symbolic and non-symbolic numerical representations, although evidence in the field is still mixed. The aim of the present study is to investigate whether symbolic and non-symbolic numerals interact in the SNARC effect when both information is simultaneously displayed. To do so, participants were presented with dice-like patterns, with digits being used instead of dots. In two separate magnitude classification tasks, participants had to respond either to the number of digits presented on the screen or to their numerical size. In the non-symbolic task, they had to judge whether the digits on the screen were more or less than three, irrespective of the numerical value of the digits. In the symbolic task, participants had to judge whether the digits on the screen were numerically smaller or larger than three, irrespective of the number of digits being present. The results show a consistent SNARC effect in the symbolic task and no effect in the non-symbolic one. Furthermore, congruency between symbolic and non-symbolic numerals did not modulate the response patterns, thus supporting the idea of independent representations and questioning some propositions of current theoretical accounts.

The temporal dynamics of emotion comparison depends on low-level attentional factors

Humans are predisposed to attend to emotions conveyed by facial expressions. However, compulsory attraction to emotions gets challenging when multiple emotional stimuli compete for attention, as in the emotion comparison task. In this task, participants are asked to choose which of two simultaneously presented faces displays the most positive (happiest) or negative (angriest) emotion. Participants usually respond faster to the face displaying the most intense emotion. This effect is stronger for face pairs that contain globally positive rather than negative emotional faces. Both effects are consistent with an attentional capture phenomenon driven by the perceptual salience of facial expressions. In the present experiment, we studied the temporal dynamics of attentional capture in the emotion comparison task by tracking participants' eye movements using gaze-contingent displays and responses. Our results show that, on the first fixation, participants were more accurate and dwelled longer on the left target face when it displayed the most intense emotion within the pair. On the second fixation, the pattern was reversed, with higher accuracy and longer gaze time on the right target face. Overall, our pattern of gazing behavior indicates that the typical results observed in the emotion comparison task arise from the optimal combination over time of two low-level attentional factors: the perceptual salience of emotional stimuli and the scanning habit of participants.

Attentional capture in emotion comparison is orientation independent

Recent findings on emotion comparison show a typical pattern of motor reactivity rising from attentional capture. When pairs of emotional faces are presented simultaneously, the most intense emotional face is recognized faster (Emotional Semantic Congruency-ESC effect). Furthermore, a global response speed advantage for emotional pairs with positive rather than negative average emotion intensity is observed (i.e., emotional size effect), with the choice for the happiest face resulting in a faster response than the choice for the angriest face within the pair (i.e., the happiness advantage). In two experiments, we asked whether these effects are orientation dependent, and thus linked to whether face processing is holistic or part-based. Participants were asked to choose the angriest/happiest face in emotional pairs displayed either in upright or inverted orientation and including (Experiment 1) or not including (Experiment 2) a neutral face. Beyond an overall facilitation for upright relative to inverted pairs, results showed orientation independent ESC and emotional size effects. Furthermore, the happiness advantage was present in emotional pairs of Experiment 2 but not in emotional pairs of Experiment 1, independently from face orientation. Together, results suggest that attentional capture in emotion comparison is immaterial on the type of face processing, being orientation invariant.

A systematic investigation reveals that Ishihara et al.'s (2008) STEARC effect only emerges when time is directly assessed

The Spatial-TEmporal Association of Response Codes (STEARC) effect (Ishihara et al. in Cortex 44:454-461, 2008) is evidence that time is spatially coded along the horizontal axis. It consists in faster left-hand responses to early onset timing and faster right-hand responses to late onset timing. This effect has only been established using tasks that directly required to assess onset timing, while no studies investigated whether this association occurs automatically in the auditory modality. The current study investigated the occurrence of the STEARC effect by using a procedure similar to Ishihara and colleagues. Experiment 1 was a conceptual replication of the original study, in which participants directly discriminated the onset timing (early vs. late) of a target sound after listening to a sequence of auditory clicks. This experiment successfully replicated the STEARC effect and revealed that the onset timing is mapped categorically. In Experiments 2, 3a and 3b participants were asked to discriminate the timbre of the stimuli instead of directly assessing the onset timing. In these experiments, no STEARC effect was observed. This suggests that the auditory STEARC effect is only elicited when time is explicitly processed, thus questioning the automaticity of this phenomenon.

Cross-cultural evidence of a space-ethnicity association in face categorisation

According to a space-valence association, individuals tend to relate negatively- and positively-connoted stimuli with the left and right side of space, respectively. So far, only a few studies have explored whether this phenomenon can also emerge for social dimensions associated with facial stimuli. Here, we adopted a cross-cultural approach and conducted two experiments with the main aim to test whether a left–right space-valence association can also emerge for other- vs. own-race faces. Asian Japanese (Experiment 1) and White Italian (Experiment 2) participants engaged in a speeded binary classification task in which a central placed face had to be classified as either Asian or White. Manual responses were provided through a left- vs. right-side button. In both experiments, other-race faces elicited faster responses than own-race faces, in line with the well-documented other-race categorisation advantage. Moreover, evidence of an association between space and ethnic membership also arose and, interestingly, was similar in both groups. Indeed, Asian faces were responded to faster with the right-side key than with the left-side key, whereas response side had no effect for White faces. These results are discussed with regard to possible cross-cultural differences in group perception.

Is Face Age Mapped Asymmetrically onto Space? Insights from a SNARC-like Task

The magnitude associated with a stimulus can be spatially connoted, with relatively smaller and larger magnitudes that would be represented on the left and on the right side of space, respectively. According to recent evidence, this space–magnitude association could reflect specific brain asymmetries. In this study, we explored whether such an association can also emerge for face age, assuming that responders should represent relatively younger and older adult faces on the left and on the right, respectively. A sample of young adults performed a speeded binary classification task aimed at categorising the age of a centrally placed adult face stimulus as either younger or older than the age of a reference face. A left-side and a right-side response key were used to collect manual responses. Overall, older faces were categorised faster than younger faces, and response latencies decreased with the absolute difference between the age of the target stimulus and the age of the reference, in line with a distance effect. However, no evidence of a left-to-right spatial representation of face age emerged. Taken together, these results suggest that face age is mapped onto space differently from other magnitudes.

Different mechanisms of magnitude and spatial representation for tactile and auditory modalities

The human brain creates an external world representation based on magnitude judgments by estimating distance, numerosity, or size. The magnitude and spatial representation are hypothesized to rely on common mechanisms shared by different sensory modalities. We explored the relationship between magnitude and spatial representation using two different sensory systems. We hypothesize that the interaction between space and magnitude is combined differently depending on sensory modalities. Furthermore, we aimed to understand the role of the spatial reference frame in magnitude representation. We used stimulus–response compatibility (SRC) to investigate these processes assuming that performance is improved if stimulus and response share common features. We designed an auditory and tactile SRC task with conflicting spatial and magnitude mapping. Our results showed that sensory modality modulates the relationship between space and magnitude. A larger effect of magnitude over spatial congruency occurred in a tactile task. However, magnitude and space showed similar weight in the auditory task, with neither spatial congruency nor magnitude congruency having a significant effect. Moreover, we observed that the spatial frame activated during tasks was elicited by the sensory inputs. The participants' performance was reversed in the tactile task between uncrossed and crossed hands posture, suggesting an internal coordinate system. In contrast, crossing the hands did not alter performance (i.e., using an allocentric frame of reference). Overall, these results suggest that space and magnitude interaction differ in auditory and tactile modalities, supporting the idea that these sensory modalities use different magnitude and spatial representation mechanisms.

A SNARC-like effect for music notation: The role of expertise and musical instrument

The Spatial-Numerical Association of Response Codes (SNARC) suggests the existence of an association between number magnitude and response location, with faster left key-press responses to small numbers and faster right key-press responses to large numbers. We investigated whether a similar association exists between musical notes on the stave and the space of response execution, involving amateur and expert musicians (Experiment 1). Moreover, in Experiment 2 we further investigated such association in two groups of expert musicians (piano and transverse flute players) who differ in the note mapping on their instruments. Results indicate a clear association between musical notes and the space of response execution only for musicians with formal education. Furthermore, this association seems not to be influenced by the specific instrument played, as both piano and transverse flute players showed the same effect direction (left key-press advantage for low notes, and vice versa).

Large as being on top of the world and small as hitting the roof: a common magnitude representation for the comparison of emotions and numbers

Previous work on the direct speed-intensity association (SIA) on comparative judgement tasks involved spatially distributed responses over spatially distributed stimuli with high motivational significance like facial expressions of emotions. This raises the possibility that the inferred stimulus-driven regulation of lateralized motor reactivity described by SIA, which was against the one expected on the basis of a valence-specific lateral bias, was entirely due to attentional capture from motivational significance (beyond numerical cognition). In order to establish the relevance of numerical cognition on the regulation of attentional capture we ran two complementary experiments. These involved the same direct comparison task on stimulus pairs that were fully comparable in terms of their analog representation of intensity but with different representational domain and motivational significance: symbolic magnitudes with low motivational significance in experiment 1 vs. emotions with rather high motivational significance in experiment 2. The results reveal a general SIA and point to a general mechanism regulating comparative judgements. This is based on the way spatial attention is captured toward locations that contain the stimulus which is closest in term of relative intensity to the extremal values of the series, regardless from its representational domain being it symbolic or emotional.

The influence of encoding and testing directions on retrieval of spatial information in explored and described environments

The verbal descriptions of an environment elicit a spatial mental model, in which the linear disposition of the described objects might be related to the properties of the description. In particular the direction from which the environment is encoded might shape the spatial mental model, as a consequence of a cultural bias in reading and writing direction. The aim of the present study was to examine the influence of the direction in which objects are encoded on the retrieval of spatial information. In two experiments we asked participants to encode an environment through either physical exploration or verbal description, that are encoding modalities which preserve the sequential presentation of spatial information. We manipulated both the encoding and testing directions of the spatial information, and tested participants by using a two-alternative forced choice task. In both experiments, the results did not reveal any significant effect, disconfirming the idea of the left-right cultural bias for western people for this type of task. The lack of effect suggests that encoding an environment through physical movement and verbal descriptions determines the development of a mental representation which is relatively independent from encoding sequential order.