|Original Paper||(1) Quoted text from original paper indicating prediction of interest to researchers||(2) Study design||(3) Key statistical result||(4) Quoted text form original paper with statistical result||(5) Results||(6) Robustness results|
|Hirai & Hiraki (2005)||However, how neural activity in response to BM changes with development has not been investigated. In the present study, based on the results of psychological and neuroimaging studies and a previous study of ours, we measured ERPs in 8-month-old infants to elucidate changes in neural activation in response to BM. We also measured ERPs in adults under the same experimental conditions as for the infants, both to confirm the results of our earlier study  and to evaluate the validity of the experimental conditions that were used in the present one. |
To avoid a loss of statistical power  and to improve the signal-to-noise ratio, we collapsed 26 electrodes into two sites around the electrodes that were used to record from the bilateral occipitotemporal regions.
The latency range was based on adult ERPs from our earlier study in which two negative peaks were observed within 200 to 300 ms of the stimulus onset .
|2 (laterality: left vs right) x|
2 (stimulus type: BM vs scrambled)
attenuated vs reversed unclear!
Main effect of stimulus?
--> reported as ns
Two simple effects?
--> not reported
|The averaged ERPs were analyzed by a two-way analysis of variance (ANOVA) (laterality vs. stimulus type) which revealed that only the laterality x stimulus type interaction was significant [ F(1,6)=7.1, p<0.05]. We then analyzed the main effect of the interaction, which revealed that: (1) during perception of BM, the averaged amplitude in the right hemisphere was greater than that in the left hemisphere [ F(1,12)=7.1, p<0.05], and (2) the amplitude of the response to BM was significantly greater than that to SM in the right hemisphere [F(1,12)=6.7, p<0.05].||F(1,6)=7.1, p<0.05|
|Reid et al. (2006)||Behavioural studies suggest that recognition of a human figure PLD is reduced, although not eliminated, when a PLD is shown inverted . Additionally, previous infant research indicates a familiarity preference for upright PLDs depicting adult locomotion . We hypothesized that the perception of biological motion would manifest itself in an increase in amplitude at posterior scalp sites between 200 and 300 ms in the upright condition relative to the inverted condition. This hypothesis was derived from event-related potential (ERP) studies investigating face processing during infancy, where familiarity with the presented stimuli has been shown to modulate the ERP amplitude in this latency in a manner similar to adult processing manifested on the N170 waveform . Indeed, in infant research, the P220–P290 waveform has been named the ‘infant N170’ due to the many cognitive and perceptual properties that it appears to share with this adult waveform . Critically, the N170 in adults, at a variety of posterior locations, including occipital (O1, O2), temporal (T7, T8) and parietal cortex (P7, P3, P4, P8) has been indicated as playing a strong role in the perception of biological motion, with more activation in the right hemisphere than in the left hemisphere [10,12].||a) two-cell: upright vs inverted|
b) 2 (stimulus type: upright vs inverted) x 2 (laterality: left vs right)
|a) Difference of means|
b) Two-way interaction
|For statistical analysis a time window was chosen around the amplitude peak of the effect from 200 to 300 ms after stimulus onset. ERPs were evaluated statistically by computing the following regions of interest (ROIs): left posterior (P3, CP5) and right posterior (P4, CP6). Variances of ERPs were analysed by a 2×2 repeated measures ANOVA. Analysed factors were (1) orientation (upright×inverted) and (2) lateralization (left×right). We assessed the ERP difference in upright and inverted conditions by considering the mean amplitude in the two conditions. An ANOVA was performed in parietal regions as previous research with adults has suggested that this location may be related to the processing of biological information [10,12]. The ANOVA indicated that there was an interaction between lateralization and orientation, with amplitude differences between conditions in right parietal regions at the latency 200–300 ms when compared with those in the left hemisphere [F(1,11) = 6.767, p = 0.025]. As expected, the amplitude was larger in the right hemisphere for upright PLDs (M= 1.95μV, S.E.: 1.23) than for inverted PLDs (M= 0.34μV, S.E.: 1.23) (see Figs. 1 and 2). The grand average and individual averages did not suggest that any other effects were evident at any scalp location (see Fig. 2). No other effects were found.||F(1,11) = 6.767, p = 0.025|
|Reid et al. (2008)||Based on previous research (e.g. Hirai and Hiraki, 2005), we hypothesized that the perception of biological facets of the stimuli would manifest themselves in a parietal location with an increase in positivity for the biological motion compared to the biomechanically impossible motion. In addition, to further investigate infant perceptual processing of movement, we presented infants with stimuli that were biologically possible in their movement but contained a corrupted human body schema. Based on adult research (e.g. Chaminade et al., 2005) should infants discriminate normal human from nonhuman corrupted body schema, we predict differential processing in parietal and frontal regions.||a) parietal region: two-cell: possible vs impossible|
b) 2 (stimulus type: possible vs corrupted) x 2 (ROI: parietal vs frontal)
|a) Difference of means|
b) Two-way interaction
|a) The analysis of mean amplitude in the parietal area from 300-700 ms indicated that there was a main effect of condition, F(2,28)=3.535, P=0.043. Follow up paired samples t-tests comparing conditions indicated that the effect was primarily due to significant differences between biologically possible and biomechanically impossible PLDs, t(14)=2.312, P=0.036, reflecting a greater positivity in parietal regions for biomechanically impossible PLDs (M=13.35 microvolts, SE 2.85) than for possible PLDs (M=6.28 microvolts, SE 2.57); see Figure 2. A statistical trend was also found indicating differences between biologically possible but schematically corrupted PLDs and impossible PLDs, t(14)=1.803, P=0.093, reflecting a trend towards greater positivity in parietal regions for biomechanically impossible PLDs (M and SE as above) than for biologically possible PLDs with corrupted schematics (M=7.04 mV, SE 2.69).|
b) For frontal regions, a time window was chosen around the peak of a clearly defined component from 200–350 ms after stimulus onset (shown as 100–250 ms after the zero point in Figure 3 due to the inclusion of 100 ms of PLD in the baseline epoch). ERPs were evaluated statistically by assessing the following frontal and central channels: F7, F3, Fz, F4, F8, FC3, FC4, C3, Cz and C4. The results of the ANOVA indicated that there was a main effect of condition, F(2,28)=5.517, P=0.01. Follow up paired-samples t-tests comparing conditions indicated that the effect was a result of significant differences between schematically corrupted PLDs and the other two conditions, namely biologically possible and biomechanically impossible motion. The paired samples t-tests displayed the following results: schematically corrupted PLDs vs biologically possible PLDs, t(14)=2.142, P =0.05; schematically corrupted PLDs vs biomechanically impossible PLDs, t(14)=2.735, P=0.016. This analysis reflected a reduced negativity in frontal regions for schematically corrupted PLDs (M=2.72 mV, SE 2.07) than for possible PLDs (M=7.67 mV, SE 3.21) and biomechanically impossible PLDs (M=9.95 mV, SE 2.93); see Figure 3. No other effects were evident at any scalp location at any time.
|a) t(14)=2.312, P=0.036|
b) not reported. Alternative: two simple effects (possible vs corrupted parietal vs frontal): t(14)=1.803, P=0.093; t(14)=2.142, P =0.05
|Marshall & Shipley (2009)||Based on prior behavioral work, we expected the ERP in 5-month-olds to be sensitive to the contrast between the scrambled displays and canonical, upright versions of the same stimuli. (…) Finally, as noted earlier, ERP work with older infants has suggested that the processing of biological motion is lateralized toward the right hemisphere, especially at temporal parietal sites (e.g., Reid et al., 2006). Given the suggestion that the localization of cognitive functions in the infant brain proceeds from more distributed to more local processing networks (Johnson, 2000), we also had the opportunity to see if this pattern of lateralization was diminished in early infancy.||a) two-cell: canonical vs scrambled|
b) 2 (stimulus type: canonical vs scrambled) x 2 (lateralisation: left vs right)
|a) Difference of means|
b) Two-way interaction
|Wilcoxon signed-rank tests were used within each 100-msec epoch in order to test for statistical significance between the waveforms to the canonical and scrambled stimuli within each electrode site. This non-parametric test was preferred because of non-normality in the distribution of the ERP amplitudes. At mid-parietal and occipital sites, the canonical stimuli produced a more positive-going waveform relative to the scrambled stimuli. The statistical comparison of the two conditions revealed a significant difference (p < .05) over a relatively long period of stimulus presentation (800–2,000 msec) at the left mid-parietal site (P3), with a difference over a shorter epoch (1,300 - 1,800 msec) being apparent for the right mid-parietal site (P4). At occipital sites, there was a significant difference (p < .05) in the right hemisphere (O2) between 800 and 1,300 msec, but there were no significant differences at the left occipital site (O1). At lateral parietal and temporal sites, the waveform elicited to the scrambled PLDs was more positive than the waveform to the canonical displays. At both lateral parietal sites (P7 and P8), significant differences between the conditions (p < .05) were first apparent in the 500–600-msec epoch and continued through the remainder of the 2,000-msec analysis epoch. At temporal sites, the difference between conditions only reached significance in the right (T8; from 600–700 msec to the end of the analysis epoch) and but not the left (T7) hemisphere.||no usable test statistics reported|